New World Screwworm

“Report, Don’t Hide It”: Experts Urge Rapid Action When Suspecting New World Screwworm

Tue, 28 Apr 2026 22:13:56 GMT

As New World screwworm edges closer to the U.S., industry leaders urge producers to shift from worry to action.

Early detection, prompt reporting and treatment — backed by coordinated surveillance along the border — will be critical to keeping this treatable pest contained. Ranches are tightening calving seasons , upgrading working facilities and revisiting parasite control plans with their veterinarians. The core message to the fight against NWS: nothing replaces “eyes on animals.”

“We’ve been preparing for the possibility of screwworms emerging back in Texas for the past year,” says Jason Sawyer, East Foundation chief science officer. “We have decided to take the attitude of preparedness. We expect we’re going to have it. How can we best manage it and best mitigate and really, how do we minimize the impact while we weather the storm?”

The Breakthrough Symposium: NWS Preparedness panel (pictured l to r) are: Jason Sawyer, East Foundation; Dr. TR Lansford III, Texas Animal Health Commission; Dr. Diane Kitchen, Florida Department of Agriculture; Stephen Diebel, Texas beef producer and Texas & Southwestern Cattle Raisers Association president; and Dr. Megan Schmid, USDA-APHIS.

(Angie Stump Denton)

Sawyer participated in a panel during the The Breakthrough Symposium: NWS Preparedness, hosted by Merck Animal Health. The panelists didn’t debate whether NWS will arrive — they spoke as if it is already on the way. For producers, that means decisions must be made months in advance: adjusting breeding and calving windows to avoid peak risk, investing in better handling facilities and building a clear response plan with veterinarians. Combined with federal and state surveillance using fly traps, animal inspections and producer reports, these risk‑based steps can help ensure that when NWS appears, it is found fast, hit hard and kept from spreading.

With cattle markets at all‑time highs, panelists warn NWS must be managed in a way that protects both animal health and commerce. Movement controls, inspection and treatment protocols, and animal disease traceability are being designed to regionalize the problem — not shut the industry down.

Here are seven key takeaways from the panel discussion:

1. Prepare, Don’t Panic

New World Screwworm is a serious but manageable threat with proper planning and coordination.

“This isn’t a ‘sell the ranch and get out of business’ problem,” Sawyer summarizes. “This is a ‘let’s figure out the best way to move forward and minimize impact.’” Today’s challenge is to rebuild the “lost muscle memory” with modern tools and a risk‑based mindset. That means planning calving seasons with NWS risk in mind, enhancing parasite control without driving resistance and being ready to isolate, treat and recheck any affected animals in close coordination with veterinarians. The sooner producers start planning, the smaller and shorter the “storm” will be for everyone.

Some strategies producers should consider include:

Get a premise ID now, if you don’t have one.
Consider shifting calving and processing into lower‑fly windows.
Manage wounds differently . Any break in the skin — navels, castration, dehorning, tags and tick bites — becomes a high‑risk site once NWS is in the area.

Dr. Diane Kitchen, a cattle rancher and Florida Department of Agriculture veterinarian manager, bovine and cervidae programs, suggests producers consider using a preventative or at least a protectant to the area to minimize the chance of an infestation occurring.

Sawyer, who manages ranches near the U.S.-Mexico border, explains. “We’re trying to work with the weather instead of against it and think about comprehensive parasite control strategies that can minimize that risk for newborn calves, knowing that we’re unlikely to be able to put our hands on every one of them as they hit the ground.”

2. Eyes on Animals, Surveillance is Central.

Nothing replaces routine, disciplined visual checks — especially of newborns and any animal with a wound. Kitchen says preparation starts with understanding NWS targets wounds and certain high‑risk areas. The fly’s preference is umbilical cords, she stresses.

“It can also affect certain mucus membranes,” she explains. “The corners of the eye, the genital tract. In particular, cows that are calving, they’re attracted to the same umbilical cord scent.” External wounds can be tiny, internal damage massive. “The wound itself externally may be very small,” Kitchen says. “The size of a quarter. But then when you go to treat there may be gallons of maggots within underneath.”

Producers who have dealt with the pest often describe it as a smell you’ll never forget , noting that the stench of a calf infested with New World Screwworm is often the first warning sign.

Dr. Megan Schmid, USDA-APHIS Cattle Health Center assistant director, explains there are two types of surveillance:

Active surveillance: Fly traps along the border, border inspectors and Wildlife Services checking animals
Passive surveillance: Producers, vets, shelters and others seeing maggots/myiasis and reporting. “The traps are helpful,” she says. ”But they’re not as sensitive as the animal inspection. So really, that’s the key part: everybody looking for the infestations in animals.”

Producers can use technology to get more “eyeballs” on cattle and keep spread to a minimum. Game cameras, virtual fencing and behavior tags can help producers find problems sooner when labor is tight.

Because these infestations can be deceptive, producers should learn to identify the specific signs of New World Screwworm , such as unusual discharge or larvae deep within living tissue.

3. Report First, Don’t Hide It.

NWS is a reportable foreign animal disease. Early reporting is critical and legally required. Officials would rather investigate 1,000 false alarms than miss one real case.

Kitchen stresses failure to report will create many more flies.

“Failure to report results in multiple generations of additional flies, which just dramatically increases the population that’s available to impact everybody,” she explains. “If you think that because you didn’t report yours, that it’s not going to be found. It will be found because it’ll be found in something else.”

She encourages producers to think about the impact on their neighbor.

If the roles were reversed, she asks, “If you hear that somebody, your neighbor, is one that didn’t report, how happy are you going to be with them?”

4. Vet Relationships Are Essential.

A veterinarian is central to preparation and treatment plan. For wound care, antibiotics, pain management and access to tools, a veterinary client–patient relationship is vital. Treatment is about parasite removal and wound management, guided by vets.

Panel members explain part of being prepared is sitting down now with your veterinarian and discussing: “If we get screwworm, what’s our plan? How often are we looking at cattle, what products are we going to use, and what do we do about movements?”

Read more about how NWS is an infestation, not an infection.

5. Wildlife Matters in This Fight.

Wildlife are a major reservoir and economic driver, and can suffer large population impacts without control. Kitchen predicts in infested areas 70% to 80% of white-tailed fawn crops could be lost.

“Our wildlife populations are both so much more abundant than they were in the 1950s and so much more valuable than they were in the 1950s,” Sawyer says. “Unfortunately, the opportunity to intervene for wildlife is much smaller. There’s really not very many strategies that are viable, and so surveillance and monitoring become really our front line of defense in terms of our wildlife populations.”

He suggests the best way to protect wildlife is aggressive control in livestock to reduce environmental burden.

6. Quarantines Are Tools, Not Punishments.

The goal is continuity of business with safeguards , not shutting down commerce. Regulators are trying to balance containment with commerce. The goal is to maintain the “speed of commerce” while using structured movement protocols to protect markets and disease-free areas.

“It’s not going to be business as usual, but it’s going to be business is still possible,” Schmid says. “The focus is: how do we allow safe movements, not restrict and stop business.”

She says the New World Screwworm Response Playbook includes guidance documents and explains the quarantine/movement framework.

Stephen Diebel, Texas beef producer and Texas & Southwestern Cattle Raisers Association president, encourages producers not to think in terms of a hard quarantine. A structured process of treatment, surveillance, inspection and certification will allow movement.

Dr. TR Lansford III, Texas Animal Health Commission assistant state veterinarian and deputy executive director, encourages producers to reference the lessons learned from fever ticks as a strategy for dealing with NWS. He notes experience with fever ticks has shaped how Texans think about area quarantines, treatment protocols and continuity of business.

7. More Tools in the Toolbox.

Panelist members summarize a holistic ectoparasite program using modern products plus strong producer education is a main NWS defense strategy.

Kitchen stress producers and veterinarians have many more tools than they did back in the ’60s and ’70s when NWS was last endemic in the U.S.

Producers can find a list of approved treatment and prevention strategies on the FDA website .

Sawyer suggests producers work with their veterinarians to plan prevention and treatment strategies. He also stresses the importance of considering resistance management.

“We don’t want to react to an emergent threat in a way that then creates problems with a persistent pest that’s already present,” he says.

Read More About How Sterile Flies are the No. 1 Tool to Fight NWS:
Doubling the Defense: USDA’s “Male-Only” Fly Breakthrough to Transform Screwworm Eradication
Border Remains Closed: Sterile Fly Production Facility Groundbreaking Next Step in Screwworm Fight

While NWS is a serious and emotionally charged threat, panelists remind producers the U.S. has pushed it back before — and can do it again.

“This pest existed here before, and it has been eradicated from the U.S. before,” Sawyer summarizes. “We know how to do it. We just have to sort of build the capacity and muscle to get it done again when we need to.”

Screwworm Fight: $750M Sterile Fly Facility Groundbreaking in Texas

Fri, 17 Apr 2026 20:33:46 GMT

USDA officially broke ground on a $750 million sterile fly production facility Friday in Edinburg, Texas, marking a major escalation in the fight against the New World screwworm (NWS). Located at Moore Air Base, this facility will provide the U.S. with a domestic supply of sterile flies — up to 300 million per week — to protect livestock, wildlife and the national food supply chain from the invasive parasite.

During the groundbreaking ceremony, Agriculture Secretary Brooke Rollins said she did not have an announcement about the reopening of the U.S.-Mexico border. On Wednesday, a report from a state official in Mexico incorrectly claimed that USDA has set a date to resume livestock imports from Mexico. According to Rollins and an USDA APHIS social media post , the claim is not accurate.

“Every day we are analyzing,” she says. “We’ve never been in a better position than we are in today, to a path. Now, I want to be very clear: New World screwworm is only about 200 miles from this border, so there will not be a port opening in Texas until it is significantly pushed back. But New World screwworm is roughly around 800 miles from the Douglas, Ariz., port and the two ports in New Mexico. So, we are looking every day to make sure we are protecting our livestock and national security.”

Rollins did announce she will be at the Douglas port next Friday, April 24, taking a firsthand look at that border crossing.

How Close Is NWS to the U.S.?

As of April 16, Mexico reports 1,300 active NWS cases in animals, with 746 cases in bovine. The latest case status map shows two active cases in the Nuevo León area, approximately 90 miles from the Texas border. The most recent case was a 7-day-old calf. On April 10, there was a canine located in the municipality of Monterrey also in Nuevo León. Along the coast south of Brownsville, in the state of Tamaulipas, there are multiple cases reported in the last week in young bovine.

USDA continues to distribute sterile flies in those NWS hot zones.

How Does Sterile Fly Production Stop Screwworm?

A sterile fly production facility plays a crucial role in NWS prevention and response. In a biosecure environment, NWS flies are raised and sterilized using irradiation before being released in targeted areas. Because female screwworm flies mate only once, mating with sterile males results in eggs that do not hatch. Sterile insect technique, paired with surveillance, animal movement restrictions, and education and outreach, has been the foundation of successful NWS eradication efforts for decades.

“Breaking ground on this facility marks a major investment in safeguarding America’s livestock and the producers who feed this nation. This puts NWS sterile fly production in American hands, so we do not have to rely on other countries for the best offensive measure to push screwworm away from our borders,” Rollins says. “The New World screwworm threatens the health of our herds, the stability of rural economies, and the resilience of our supply chain. President Trump and his entire cabinet is committed to leveraging every resource necessary to contain this pest, protect American agriculture, and ensure the long-term security of our food supply chain.”

Today at the Southern Border, we officially broke ground on @USDA’s new sterile New World Screwworm production facility.🇺🇸

For months, we’ve been on offense:
• Monitoring 8,000+ traps along the southern border
• Testing nearly 51,000 fly specimens — all negative
•… pic.twitter.com/VUE1KrX4TA
— Secretary Brooke Rollins (@SecRollins) April 17, 2026

Rollins was at Moore Air Base Feb. 9 for a grand opening of a sterile fly dispersal facility at the same location. This facility expanded USDA’s ability to disperse sterile flies along the border and into the U.S., if necessary.

What is the Timeline for the Edinburg Facility?

“Once operational, this facility will initially produce an additional 100 million sterile flies per week in phase one, but eventually, when we get to Stage 2, which will be the end of 2028, we’ll be at 300 million sterile flies. When you combine that with all of the other flies that are being produced, that moves us from containment to eradication,” Rollins emphasizes.

Also at the groundbreaking was Lt. Gen. William H. “Butch” Graham, U.S. Army Corps of Engineers (USACE) commanding general.

“Our mission at USACE is to deliver engineering solutions, with our partners, to secure our nation, strengthen our economy, and reduce disaster risk,” Graham says. “That’s why we’re proud to deliver an engineering solution to the New World Screwworm, which represents a direct threat to our nation’s livestock, our food security and our economy. This new, modern facility is the critical infrastructure we need to secure a defensive line against the New World screwworm for generations to come.”

The new facility is being built with an aggressive timeline designed to quickly expand the nation’s sterile fly production capacity:

Initial operational capability targeted for November 2027, reaching production of 100 million sterile flies per week.
Construction continues immediately beyond initial operations to scale full production capacity to 300 million sterile flies per week.
USDA and USACE have slashed red tape, securing expedited procurement, and eliminating other barriers.
Together, USDA and USACE will oversee installation and commissioning of specialized systems that will make this facility operable on time, delivering the critical sterile flies we need to continue to defeat this pest.

Why is Domestic Fly Production Important for U.S. Agriculture?

This new state-of-the-art facility will complement USDA’s ongoing production of 100 million sterile flies per week at the Panama-based COPEG facility . USDA has also invested $21 million to support modernization of a facility in Metapa, Mexico, expected to be operational in summer 2026.

According to a USDA press release : “Once fully operational, this expanded production network will provide the speed, scale, and domestic capability needed to rapidly counter any NWS threat — reducing risks to producers, protecting animal health, and strengthening the resilience of America’s livestock industry.”

Read more about why the border is closed and its impact:
The 1.1 Million Head Gap: Analyzing the Impact of the U.S.-Mexico Border Closure
Should Beef Producers Be Concerned About Potential Phased Reopening of U.S.-Mexico Border?
From Lawsuits to Screwworms: Policy Uncertainty Rolls Downhill to Producers

USDA’s "Male-Only" Fly Breakthrough to Transform Screwworm Eradication

Fri, 10 Apr 2026 15:27:40 GMT

USDA’s Agricultural Research Service (ARS) is advancing the next evolution of the long-trusted sterile insect technique (SIT) to protect U.S. livestock from New World screwworm (NWS) by introducing a 100% male-only sterile fly strain. This breakthrough will effectively double the production capacity of sterile fly facilities without expanding physical infrastructure. By eliminating the production of “useless” female flies, the USDA-ARS innovation aims to push the NWS fly further south, providing a more robust and cost-effective defense for American livestock producers.

A USDA spokesperson explains, “USDA is using gold standard, proven scientific methods to manufacture NWS flies to produce only male flies and increase the efficiency of SIT. USDA is simply making a proven tool even more efficient and effective to better protect America’s farmers and ranchers.”

USDA currently produces sterile flies for dispersal at the COPEG facility in Panama. USDA is also investing $21 million to support Mexico’s renovation of an existing fruit fly facility in Metapa — which will double NWS production capacity once complete.

Moore Air Base: On Time and On Budget for 2026 Production

Dudley Hoskins, USDA under secretary for marketing and regulatory programs, was a guest Tuesday on AgriTalk. He discussed sterile fly dispersal efforts.

“We’re doing two things,” he says. “One, the Secretary has us modernizing our infrastructure and our production capacity. She has us working on Moore Air Base, which will be a sterile fly production facility, that when it’s finally complete and at max-capacity production, will be producing about 300 million sterile flies per week. ”

Deputy Secretary Stephen Vaden recently reported USDA is on track and on time with regard to the Moore Air Base facility near Edinburg, Texas.

The Science of Stopping the Spread: Why Male-Only Matters

SIT, when paired with surveillance, movement restrictions and education and outreach, is an effective tool for controlling and eradicating NWS. Female NWS flies only mate once in their lives, so if they mate with a sterile male, they lay unfertilized eggs that don’t hatch. Releasing sterile flies just outside of affected areas helps ensure flies traveling to new areas will only encounter sterile mates and will not be able to reproduce.

Hoskins says concurrent to the process at Moore Air Base, USDA is working with its partners at the ARS and Environmental Protection Agency (EPA) to evaluate the genetically-engineered fly — the NovoFly — which would help get more male flies in the sterile fly production facility.

Vaden calls the possibility exciting.

“Basically we’ve been losing half of the production at every facility because what we need are sterile male flies, but of course with nature, half of what you get are female flies, and those to this particular enterprise are useless,” he explains. “Thanks to our agricultural research service, we now have the ability to pump out 100% sterile male flies only, no wastage. That has the effect of doubling production without any change in the available facilities.“

He adds, “We expect to be able, once EPA approves that innovation is safe later this year, to have all those facilities, including the one under construction at Moore Air Base, pumping out 100% sterile male flies, which will make our ability to push this pest back further south where it belongs to take root and begin to have great effect. Not just to hold it, but to push it further south.”

Hoskins summarizes, “All of those things are in motion, all things happening concurrently, and all those will be critical in modernizing our toolbox to take the fight to the screwworm.”

Listen to the conversation on AgriTalk :

Regulatory Road Map: The EPA Public Comment Period

USDA is following established regulatory pathways and submitted to EPA an Emergency Use Exemption and Application for Registration. EPA published the notice of receipt and request for comments in the Federal Register on March 27 and is accepting public comments until April 27 before making a determination.

According to the notice, the application from USDA states: “To register a new pesticide product containing an unregistered pesticide, NovoFly male-only genetically engineered (GE) New World screwworm (NWS) in USDA’s Sterile Insect Technique (SIT) programs. Additionally, the Agency received a Section 18 quarantine emergency exemption application requesting use of the same pesticide to maintain broad suppression of and help prevent the pest from moving further northward from Mexico toward the United States.”

EPA is providing the notice in accordance with the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).

The notice says, “Due to the urgent nature of the emergency, the limited time available to authorize the Section 18 quarantine emergency exemption request and the related FIFRA Section 3 product registration application under review for the same use, EPA is waiving the comment period associated with the emergency exemption request but is soliciting public comment in conjunction with the application for Section 3 product registration of NovoFly.”

To make comments or learn more, visit the EPA website .

Read more about sterile flies and current distribution:

USDA Updates New World Screwworm Response Playbook for Ranchers and Vets

Thu, 09 Apr 2026 17:28:46 GMT

The “ New World Screwworm Response Playbook” was developed as a resource to help animal health officials and responders manage and adapt their response if NWS is found in the U.S. The first draft of the Playbook was released in October 2025.

U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) released an updated Playbook to serve as a comprehensive guide to support coordinated, science-based action should NWS be detected.

“USDA continues to execute Secretary Rollins’ five-pronged plan to keep NWS out of the United States,” says Dudley Hoskins, USDA under secretary for marketing and regulatory programs. “While we are aggressively safeguarding American agriculture and working with Mexico to prevent further northward spread, we must also ensure that our domestic response plans are ready for immediate activation. Strong coordination with states, producers, veterinarians, sportsmen and other partners is essential to achieving that goal.”

Hoskins was a guest Tuesday on AgriTalk. He discussed NWS preventative and response measures, including the sterile fly dispersal efforts.

He explains the goal of the Playbook is to try to balance that constant posture of vigilance, prevention and emergency response coordination.

“We want to be as least disruptive to the industry and commerce as possible,” he explains.

Hoskins stresses APHIS is asking for feedback on version two of the Playbook as they continue to fine-tune the response plan.

“We’re asking that same community of states and industry partners to continue to review the playbook,” he explains. “We want to continue to have those discussions and and those deliberations to improve the can and hopefully perfect have to use it, and hopefully never have to use it.”

Refining the Rules: Key Updates to the 2026 Playbook

The updated Playbook outlines critical science-based strategies for federal, state, tribal and local responders, including how to:

Coordinate response operations
Reduce spread and prevent establishment of NWS in new areas
Manage the pest in infested animals
Implement NWS fly surveillance and control measures
Maintain continuity of business
Support efficient information flow and situational awareness

APHIS has released the updated New World Screwworm Response Playbook - strengthening preparedness via coordination with states, producers, veterinarians, wildlife & other partners.🤝
It guides rapid, science-based action should NWS be detected in the U.S.https://t.co/lgplvaNjDy pic.twitter.com/kq4wKbqkGY
— USDA Animal and Plant Health Inspection Service (@USDA_APHIS) April 8, 2026

Collaborative Design: Incorporating Tribal and Industry Expertise

After sharing the draft Playbook in October 2025, APHIS worked to gather feedback from state animal health officials, federal partners, livestock and wildlife industry groups, tribal partners, veterinary organizations and other key stakeholders to prepare the updated version.

According to the APHIS press release , “Their expertise and operational experience were essential in shaping practical, field-ready guidance for real-world response scenarios.”

Based on this feedback, APHIS made several key updates to the Playbook including clarifying and expanding:

Terminology — NWS establishment, suspect, zones, types, phases, quarantines — treatment versus preventative NWS animal drugs and pesticide products
Agency roles, responsibilities and authorities
Animal movement requirements
Wildlife management, including:
- Improved description of roles, responsibilities and authorities related to wildlife
- Added and improved definitions of confined, farmed, and free-ranging wildlife
- Refined guidance on use of antiparasitic drugs and pesticide for use on/in wildlife
- Development guidance on wildlife surveillance

Accessing the Playbook: Resources for Producers and Responders

APHIS updated four supplemental guidance documents that were posted with the draft Playbook and added an additional eight supplemental guidance documents, all referenced in the Playbook .

(USDA APHIS NWS Playbook)

“To ensure continued alignment with state-level plans and industry practices, APHIS will continue to revise the Playbook as preparedness activities advance and evolve,” the release explains. “The agency will continue to work directly with states, territories, tribes, federal agencies, industry wildlife and other partners to refine response tools, strengthen coordination and support joint planning efforts.”

Your Next Reads:

How Will U.S. Producers Maintain Business when New World Screwworm Invades?

Wed, 11 Mar 2026 19:59:33 GMT

With animal disease, prevention and preparation beat panic. Since New World screwworm (NWS) was last eradicated from the U.S. in the 1960s, the tools and infrastructure to deal with foreign animal disease have dramatically changed.

Dr. Justin Smith, Kansas animal health commissioner and state veterinarian, during the recent Kansas State University Cattlemen’s Day gave an update on how Kansas and other states are preparing for NWS. The approach is designed to keep producers in business, keep cattle and products moving, and manage NWS in a way that protects both herds and markets.

He says the U.S. animal health officials along with USDA are planning a multistate, coordinated response that aims for consistency across state borders.

Smith summarizes the industry’s preparation to tackle NWS is like a three-legged stool. U.S. producers will be able to maintain business when NWS invades through surveillance, treatment and movement controls.

Surveillance: Eyes on Animals

The first leg of the stool is surveillance. He stresses early detection depends heavily on producers and veterinarians watching animals closely and reporting anything suspicious.

Smith emphasizes they would rather over investigate than miss a case.

“We want to make sure that we err on the side of having to say no on many occasions, versus saying, ‘Yep, this is what we got.’ Eyes on animals is going to be key.”

He was clear this should feel like partnership, not policing.

“They don’t want it to look like Big Brother coming over your shoulder,” he explains. “I hope we want to get this thing quickly.”

Smith explains that once a positive premises is identified, surveillance becomes structured around zones. The infested premises sit at the center, surrounded by an infested zone, an adjacent surveillance zone and a broader fly surveillance area.

The infested zone is 12.4 miles in radius from the infested premises. In this zone, there will be frequent on‑animal checks for wounds and larvae, plus enhanced monitoring in surrounding zones using fly traps and animal observation. The adjacent surveillance zone is another 12.4 miles radius and then there will be a fly surveillance area — an 124-mile radius from the infested premises.

Smith says movements out of the infested zone will require visual inspection for wounds and systemic treatment, including a treatment window of three to 14 days before movement plus a documented certificate of veterinary inspection.

He says the current Kansas response plan aligns with USDA’s playbook and neighboring states’ plans while taking into account specific needs of the Kansas livestock industry.

He stresses the playbook will continue to evolve, and state-by-state implementation may vary, but he says the “zone approach” will be utilized by all states.

Treatment: Limited Tools, Use Strategically

The second leg is treatment. Smith says that after decades without large domestic outbreaks, labeled options are limited.

From the fact that we haven’t had this new tool in our nation, in a large-spread outbreak since the 60s, we don’t have a lot of treatments out there that are labeled for this organism.”

To date, the Food and Drug Administration (FDA) has approved four products for large animals:

He cautions, “The goal is not to go out there and just habitually treat your animals just in case. We want to make sure that we’re utilizing these [products] responsibly. There’s not an unlimited supply out there, and so we want to make sure that it’s available for us when we do need it.”

On a positive premises, Smith says treatment will be mandatory and systematic.

“There will be a quarantine placed on that premises. We’re also going to require a certain level of treatment on that premises,” he explains.

There will be protocols for daily mortality disposal, so carcasses don’t become breeding sites.

“The last thing you want to do is bury an animal that has larvae and has the ability to advance.”

He says treatment is also tied to movement out of infested zones, with most animals needing prophylactic treatment before leaving.

Movement Controls: Targeted, Not Statewide Shutdowns

The third leg is movement control, designed to be precise rather than broad-brush. Smith stresses NWS is an infestation, not an infection , emphasizing it is not a systemic disease problem, but an infestation that still demands strong controls.

He says there will be movement restrictions if a premises falls into an infested region. To move animals out of that zone, there will be steps to follow but movement will not be completely shut down.

He explains some exceptions exist:

Animals moving directly to slaughter can go without pre‑movement treatment, but those animals have to be hanging on the rail within 72 hours.
Baby dairy calves must be treated but can move right away if treatment and navel care are documented.

He says Kansas is also coordinating with neighboring states to create “synergistic” rules, especially for cattle from higher‑risk states such as Texas. Cattle entering Kansas from recognized infested zones will face inspection, treatment requirements and at least 14 days in drylot containment on arrival.

NWS is Not a Food Safety Issue

Smith reassures producers and consumers that NWS is not a meat safety threat.

“This is not a food safety issue,” he says. “If an animal is presented to slaughter, it has a screwworm wound then it has the ability to be trimmed. That carcass will not be condemned. There are no restrictions on any inspected product for food safety reasons.”

Smith summarizes underpinning all three legs is a commitment to dynamic planning and continuity. He notes a revised USDA playbook is forthcoming and that “plans will be a little bit dynamic” as they learn more.

The core message for producers is clear: watch your cattle, report early, use treatments wisely and expect targeted movement controls — not blanket shutdowns — if NWS crosses the border.

USDA Announces Sterile Fly Production Facility Construction Contract

USDA and U.S. Army Corps of Engineers (USACE) announced March 9 a construction contract with Mortenson Construction to build a new sterile fly production facility at Moore Air Base in Edinburg, Texas.

This facility is a key component in U.S. Secretary of Agriculture Brooke Rollins’ sweeping 5-prong strategy to fight NWS. USACE is partnering with USDA and will provide oversight for the contract, design, engineering and construction of the facility.

“The Army Corps of Engineers is an essential partner in bringing this facility to life and further highlights the Trump Administration’s government-wide effort to fight the New World Screwworm threat in Mexico,” Rollins says. “The Army Corps is the best in the business and their engineering expertise and proven track record in delivering complex projects will help ensure we can build a modern, resilient facility that protects American agriculture from invasive pests for decades to come. This first-of-its-kind facility on U.S. soil will ensure we are not reliant on other countries for sterile flies.”

A sterile fly production facility is a specialized biosecure complex where NWS flies are raised and sterilized using irradiation and then released into targeted areas.

USDA currently produces about 100 million sterile flies per week at the COPEG facility in Panama and disperses them within and just north of affected areas in Mexico. In addition to the COPEG facility in Panama, USDA invested $21 million to support Mexico’s renovation of an existing fruit fly facility in Metapa , which will double NWS production capacity once complete.

With ongoing support from APHIS technical experts, Mexico anticipates sterile fly production will begin at this facility in summer 2026. The new facility at Moore Air Base will be the only U.S.-based sterile fly production facility and will work in tandem with facilities in Panama and Mexico to help eradicate the pest and protect American agriculture.

USDA and USACE will break ground on this new facility later this spring, after initial planning and development meetings with the new contractor. By November 2027, the production facility at Moore Air Base is expected to reach its initial goal of producing 100 million sterile flies per week. After that, construction will continue at the facility to increase production with the long-term goal of producing 300 million sterile flies per week.

U.S. Begins Dropping Sterile Flies in Texas to Stop Screwworm

Sat, 31 Jan 2026 13:56:10 GMT

New World screwworm (NWS) is inching closer to the U.S. Last week Mexico reported eight new cases in the U.S. neighboring-state of Tamaulipas. A key to slowing down the threat is being proactive.

U.S. Department of Agriculture’s (USDA) import requirements and protocols are one line of defense for NWS and other foreign animal diseases that threaten U.S. livestock. According to USDA , earlier this week, a horse from Argentina was presented for routine importation at an equine import quarantine facility in Florida.

“Upon examination, APHIS identified an open wound with larvae on the animal and promptly collected and shipped samples to the National Veterinary Services Laboratories (NVSL) in Iowa. The horse was immediately treated with medication to kill any larvae in accordance with standard, long-standing import protocols.” the release explains . “This morning, NVSL confirmed that the larvae were NWS larvae. Accordingly, the animal will remain in quarantine until it has been reexamined and determined to be free of NWS.”

This is an example of import protocols working as designed. While this situation does not appear to be associated with the NWS outbreak in Mexico, the release says it underscores the need for vigilance in all of USDA’s coordinated efforts to fight NWS.

New Action To Prevent Northward Spread

Friday, Jan. 30, USDA’s Animal and Plant Health Inspection Service (APHIS) announced a shift in its 100-million-per-week sterile fly dispersal efforts .

“USDA will reallocate aircraft and sterile insects to reinforce coverage along the U.S.-Mexico border,” according to the release. “The new dispersal area, or polygon, will include operations about 50 miles into Texas, along the U.S. border with the state of Tamaulipas, Mexico. Mass production and targeted dispersal of sterile insects are critical components of an effective strategy to fight NWS. Other tools including import protocols and surveillance continue to support these robust efforts to keep NWS out of the U.S.”

Dudley Hoskins, USDA undersecretary of marketing and regulatory programs, says, “At Secretary Rollins’ direction, our highest priority is protecting the United States from screwworm. The northernmost active case of NWS in Mexico is still about 200 miles away from the border, but we’ve seen cases continue to spread in Tamaulipas and further south in Mexico, so we are proactively shifting our polygon as we make every effort to prevent NWS from reaching our border.”

This follows Texas Gov. Greg Abbott’s actions on Thursday issuing a statewide disaster declaration to better equip the Texas NWS Response Team to prevent the potential spread of the NWS fly into Texas and to better protect livestock and wildlife.

“Although the New World screwworm fly is not yet present in Texas or the U.S., its northward spread from Mexico toward the U.S. southern border poses a serious threat to Texas’ livestock industry and wildlife,” said Governor Abbott. “State law authorizes me to act to prevent a threat of infestation that could cause severe damage to Texas property, and I will not wait for such harm to reach our livestock and wildlife. With this statewide disaster declaration, the Texas NWS Response Team can fully utilize all state government prevention and response resources to prevent the re-emergence of this destructive parasite. Texas is prepared to fully eradicate this pest if need be.”

Sterile Flies are Key to Stopping NWS

Sterile insect technique, when paired with surveillance, movement restrictions and education and outreach, is an effective tool for controlling and eradicating NWS. Female NWS flies only mate once in their lives, so if they mate with a sterile male, they lay unfertilized eggs that don’t hatch.

Releasing sterile flies just outside of affected areas helps ensure flies traveling to new areas will only encounter sterile mates and will not be able to reproduce.

The updated strategy will include: “USDA will release sterile flies north of the current active NWS cases in Mexico in a proactive effort to create a sterile reproduction buffer zone if the fly moves north from Mexico.”

Because it is important to continue ongoing surveillance efforts while releasing sterile insects, it is possible that sterile NWS flies could be caught and/or reported within Texas. To ensure officials can tell the difference between sterile and wild NWS flies, USDA will dye the sterile pupae, and the dye will transfer to the sterile flies when they hatch. The fluorescent dye will glow under UV light and may also be visible to the naked eye. If a sterile fly is captured in a trap, this dye will allow animal health officials to quickly rule the fly out as a threat.

“USDA will continue to deploy its intensive NWS response efforts including implementing import protocols, ongoing surveillance and trapping efforts along the border, investing in NWS innovation, and supporting robust response activities in Mexico and Central America,” the release says.

Surveillance, Monitoring and Reporting Continues

USDA continues to lead intensive surveillance and monitoring systems along the U.S. border. Teams continue to check 121 NWS-specific traps across high-risk areas of border states and leverage thousands of fruit fly/insect traps aligned all along the Southern border. To date, more than 42,000 flies from traps in all locations have been submitted to APHIS NVSL for identification, with no NWS detections to date.

APHIS Wildlife Services is also leading a coordinated effort to inspect wildlife for signs of NWS infestation. To date, they’ve inspected more than 9,300 wild animals across 39 different species and 131 U.S. counties and found no signs of NWS infestations.

Texas Takes Preemptive Action

The Texas release says Governor Abbott actions against the threat posed by NWS include:

Directing the Texas Parks and Wildlife Department (TPWD) and the Texas Animal Health Commission (TAHC) to establish a joint Texas NWS Response Team.
Partnering with the U.S. Department of Agriculture and Secretary Brooke Rollins to create a new $750 million Domestic Sterile NWS Production Facility in Edinburg, Texas.

“I’m glad to see the urgency from the governor’s office matching the seriousness of this threat,” says Texas Ag Commissioner Sid Miller. “The Governor’s disaster declaration gives his task force greater authority, resources, and speed needed to confront the growing threat posed by the New World screwworm. This is a serious risk to our livestock industry and one that the Texas Department of Agriculture has been preparing for through our own heightened surveillance, coordination, and response planning.”

Miller adds, “This fight requires every available resource to be thrown at it without delay, and TDA will continue to work alongside our state and federal partners to protect our livestock, pets, wildlife, and Texas communities.”

For more information on NWS and USDA’s efforts, visit Screwworm.gov

USDA Announces New World Screwworm Grand Challenge

Wed, 21 Jan 2026 21:52:38 GMT

Today, U.S. Secretary of Agriculture Brooke L. Rollins announced the launch of the N ew World Screwworm (NWS) Grand Challenge. This funding opportunity marks a pivotal step in USDA’s comprehensive strategy to combat NWS and prevent its northward spread.

“This is a strategic investment in America’s farmers and ranchers and is an important action to ensure the safety and future success of our food supply, which is essential to our national security,” Rollins says. “These are the kinds of innovations that will help us stay ahead of this pest and protect our food supply and our economy, protecting the way of life of our ranchers and go towards rebuilding our cattle herd to lower consumer prices on grocery store shelves. We know we have tried-and-true tools and methods to defeat this pest, but we must constantly look for new and better methods and innovate our way to success. Together, through science, innovation, and collaboration, we can ensure we’re utilizing the latest tools and technology to combat NWS in Mexico and Central America and keep it out of the United States.”

As part of the Grand Challenge, USDA’s Animal and Plant Health Inspection Service (APHIS) will make up to $100 million available to support innovative projects that enhance sterile NWS fly production, strengthen preparedness and response strategies, and safeguard U.S. agriculture, animal health, and trade.

Priority Areas for Funding

APHIS invites proposals that support one or more of the following objectives:

Enhance sterile NWS fly production
Develop novel NWS traps and lures
Develop and increase understanding of NWS therapeutics/treatments (i.e., products that could treat, prevent, or control NWS) for animals
Develop other tools to bolster preparedness or response to NWS

The notice of funding opportunity, including application instructions, eligibility, and program requirements, is available on the NWS Grand Challenge webpage . Applicants can also find information on the ezFedGrants website  or  Grants.gov  by searching USDA-APHIS-10025-OA000000-26-0001.  

Eligible applicants are invited to submit proposals that align with and support these priorities by the deadline on February 23, 2026, at 11:59 p.m. ET.

Entities interested in submitting a proposal should ensure they are registered with the  U.S. Government System for Award Management (SAM) . Learn more about the basics of the funding process and  how to get ready to apply .  

Your Next Reads:
New World Screwworm Found in Newborn Calf 197 Miles from U.S.-Mexico Border
USDA Launches Screwworm.gov
The Smell You’ll Never Forget: A Calf Infested with New World Screwworm

New World Screwworm Confirmed in Pig in Mexico

Fri, 09 Jan 2026 18:12:31 GMT

A case of New World screwworm (NWS) was recently confirmed in a 30-month-old pig in the Mexican state of Veracruz. This state currently has 125 active cases of NWS and 1,963 total cases reported. No other information was reported from USDA when the case was listed on the NWS website Jan. 9.

As the number of cases continue to rise and inch closer to the U.S. border, livestock producers need to be on alert. NWS poses a real threat to rural America, says Texas beef producer Donnell Brown.

“Fortunately, we made it to winter without a major screwworm infestation in the United States,” he says in a recent articl e on PorkBusiness.com . “However, as temperatures rise this spring and fly season begins again, I am deeply concerned that we could see an outbreak with devastating consequences for livestock and wildlife.”

Lizeth Olivarez doesn’t know if people will have the stomach to deal with NWS. She’s a sixth-generation rancher who runs cattle in the U.S. and in Mexico at Las bendiciones Ranch in Realitos, Texas, and Rancho El Cuellareno in Guerrero, Mexico. Though she hasn’t experienced it herself, she has grown up hearing story after story about NWS from both her grandfather and father who dealt with NWS when the deadly fly struck in the 1960s.

A Threat to the U.S. Swine Industry, Too

Though only three cases have been reported in swine since July 4, 2025, the potential for infection is there, especially for domestic pigs raised outdoors and wild pigs.

Megan Niederwerder, executive director of the Swine Health Information Center (SHIC), says it’s important to remember this is not just a cattle disease ; it impacts other livestock species and humans as well.

“It’s really important to stay vigilant as we think about increasing awareness and understanding of what the fly looks like,” Niederwerder says.

Pork producers should be aware of the disease and be watchful for suspect clinical signs of myiasis (fly infestation), adds Lisa Becton, DVM, associate director of SHIC.

“Flies lay eggs in live tissue of a wound — even a wound as small as an injection site or a tick bite,” Becton says.

Producers should continue to perform normal daily animal monitoring/observations and identify suspect wounds that do not heal, have drainage or smell bad, she explains.

“Prompt treatment of scratches or other wounds with approved topical wound spray is important for everyday management of animal health/welfare,” Becton says. “Monitor other susceptible animals like newborn piglets for signs of myiasis. If lesions are suspected, contact your state veterinarian and your herd veterinarian.”

The most important thing U.S. pork producers need to know is that NWS is not currently in the U.S., Becton says. However, if you suspect an animal is affected, contact your herd and state veterinarian immediately for further investigation.

Current information related to NWS is available on the USDA Animal and Plant Health Inspection Service website , including a current situation map and table showing cases within 400 miles of the U.S.

New World Screwworm Found in Newborn Calf 197 Miles from U.S.-Mexico Border

Wed, 31 Dec 2025 16:47:26 GMT

On Dec. 27, Mexico’s National Service of Agro-Alimentary Health, Safety, and Quality (SENASICA) reported a new case of New World screwworm (NWS) in a 6-day-old calf with an umbilical lesion in Llera, located in the state of Tamaulipas, approximately 197 miles from the U.S.-Mexico border.

According to the Texas Animal Health Commission, there have been no other detections in Tamaulipas or any evidence of established fly populations in the area.

To support a swift response if NWS reaches Texas, producers located on the southern border and travelers from NWS-affected areas should closely monitor animals for signs and promptly report suspected cases of NWS.

Read more about how to identify NWS:
The Smell You’ll Never Forget: A Calf Infested with New World Screwworm
Protect Your Livestock: Signs of New World Screwworm

A suspected NWS case requires immediate action, but it all starts with one thing: your call. If you suspect an infestation, report it right away.

The Texas Animal Health Commission recently posted this video explaining the process for producers to take if they suspect a NWS case:

What Are Some Key Concerns if NWS Crosses the Border?

Texas beef producer Donnell Brown says NWS poses a real threat to rural America.

“Fortunately, we made it to winter without a major screwworm infestation in the United States,” he says. However, as temperatures rise this spring and fly season begins again, I am deeply concerned that we could see an outbreak with devastating consequences for livestock and wildlife.”

Read more about NWS and winter:
Winter: The Secret to Slowing the Spread of Screwworm

Brown recalls the previous NWS outbreak in Texas.

“Compared to the last screwworm epidemic I experienced as a child, we now have far more effective parasiticides with extended protection for livestock,” he says. “Unfortunately, we still lack practical ways to treat or protect wildlife. After the screwworms were eradicated in the 1970s, it was 15 years before I remember seeing deer on our ranch. Today, deer are abundant and hunting has become a major economic driver for ranchers and rural communities.”

Read more about NWS treatment and prevention options:

FDA Approves Exzolt Cattle-CA1 for Prevention and Treatment of New World Screwworm
FDA Approves Dectomax-CA1 for Prevention and Treatment of New World Screwworm
New Technology to Combat New World Screwworm

Browns says if NWS cause significant wildlife losses, the ripple effects would be severe.

“Fewer hunters would travel from cities to rural areas, reducing spending on food, fuel, feed, lodging and other local necessities. This would harm rural economies already under pressure,” he explains. “The risk is especially high because fawns and many other wild mammals are born during fly season. Their wet navels become prime targets for screwworm infestation, making the potential impact on wildlife populations both immediate and profound.”

Read more about NWS and wildlife:
The Importance of Wildlife Monitoring for New World Screwworm

Sterile Flies Remain Key to Eradicating New World Screwworm

“The continued detections of New World screwworm near the Texas border are grim reminders of the serious threat this pest poses to our state,” says Texas Agriculture Commissioner Sid Miller. “Thanks to the efforts of USDA Secretary Brooke Rollins and APHIS working in coordination with Mexico, its northward spread has been halted, and this recent case promises to be a one-off, for now. But to fully eradicate this threat, the bottom line remains unchanged: we need sterile flies. I said as much a year ago when I criticized the Biden Administration’s failed efforts to corral this pest — dollars don’t kill screwworms, sterile flies do.”

Under President Trump’s leadership, Secretary Rollins and the USDA have now committed to a historic, targeted response that will deliver real results.

“Earlier this year, I was proud to stand alongside Secretary Rollins in Edinburg, Texas, as she unveiled her comprehensive five-point plan , and again at the Texas Capitol as that plan was expanded ,” Miller says. “I will continue to support and advocate for federal efforts to expand sterile insect fly production and infrastructure, because this proven strategy is key to the long-term eradication of New World screwworm.”

Current information related to NWS is available on the USDA-APHIS website , including a current situation map and table showing cases within 400 miles of the U.S.

Your Next Reads:
The Battle at the Border
Preparing for the Battle Continues: USDA Shares Screwworm Update and Releases NWS Playbook

FDA Approves Exzolt Cattle-CA1 for Prevention and Treatment of New World Screwworm

Thu, 04 Dec 2025 19:35:54 GMT

On December 4, 2025, the U.S. Food and Drug Administration (FDA) granted conditional approval to Exzolt Cattle-CA1, a fluralaner topical solution from Merck Animal Health, for the use in beef cattle (≥ 2 months of age) and replacement dairy heifers (< 20 months of age). The approved uses include prevention and treatment of larval infestations by New World screwworm (NWS), and treatment and control of cattle fever tick.

“The FDA is leveraging every resource and authority at its disposal to ensure producers and veterinarians have the critical products they need to protect their livestock and safeguard our food supply against NWS and cattle fever tick,” said Timothy Schell, director of the FDA’s Center for Veterinary Medicine, in a press release . “We remain steadfast in our commitment to ensuring that animal drugs are safe and effective and that food from treated animals is safe to eat.”

While NWS has not yet been detected in the U.S., the threat persists just south of the border with a new case being reported yesterday. Cattle fever ticks, present along the U.S.-Mexico border in south Texas, are competent vectors of Babesia bovis and Babesia bigemina — agents of bovine babesiosis (Texas cattle fever).

“The threat of New World screwworm represents a growing concern to U.S. agriculture, potentially causing devastating economic losses for cattle producers that could reach hundreds of millions of dollars,” said Rick DeLuca, president of Merck Animal Health, in a news release . “We worked closely with the FDA to accelerate availability so that veterinarians and cattle producers will have access to a powerful new tool to protect cattle from these serious parasites, helping to safeguard the industry’s economic future and the nation’s beef supply.”

The conditional approval status reflects FDA’s determination that Exzolt Cattle-CA1 is safe for its labeled use and is reasonably expected to be effective, while requiring that its sponsor, Merck Animal Health, submit further data demonstrating its effectiveness over the next five years to support full approval.

Administration and Use Considerations

Exzolt Cattle-CA1 is a ready-to-use pour-on that delivers the active ingredient, fluralaner, to act systemically against infestations. Administration involves applying a narrow band of the solution from between the shoulder blades to the tailhead. It will be available in the first quarter of 2026 by prescription in 250 mL, 1 L or 5 L bottles.

After administration, there is a 98-day withdrawal period before slaughter to ensure meat from treated animals is free of drug residues. Use is prohibited in lactating dairy cattle, dairy calves, veal calves or bulls over one year of age that are intended for breeding.

This approval of Exzolt Cattle-CA1 complements that of Dectomax-CA1 , which was authorized in September 2025 for prevention and treatment of NWS infestations in cattle. Together, these two products give veterinarians and producers their first pharmacologic defenses against NWS.

Second Screwworm Detection 120 Miles from U.S. Border

Wed, 03 Dec 2025 20:54:06 GMT

There was a new detection of New World screwworm (NWS) in Montemorelos, Nuevo León, Mexico, approximately 120 miles south of the Texas border.

USDA’s Animal and Plant Health Inspection Service (APHIS) confirmed the case in a 22-month-old bovine transported from Veracruz to a feedlot in Nuevo León.

Texas Agriculture Commissioner Sid Miller in a press release emphasized that Texas remains free from detection, but that state officials and agriculture leaders cannot be complacent.

Texas Agriculture Commissioner Sid Miller today issued the following statement after being notified by the U.S. Department of Agriculture (USDA) of a new detection of the New World screwworm (NWS) in Montemorelos, Nuevo León, Mexico, approximately 120 miles south of the Texas… pic.twitter.com/Wb3uIwW3gf
— Texas Agriculture (@TexasDeptofAg) December 3, 2025

“We will keep working shoulder to shoulder with USDA, Mexican animal health authorities, and our own state agency partners to defend our border and Texans from this dangerous threat. We will protect our livestock, safeguard our economy, and do everything possible to keep the New World screwworm at bay,” Miller says.

He also encourages Texas producers to remain watchful for suspicious wounds, unhealed tissue, or maggot activity in livestock, wildlife, and pets, particularly in locations near the border.

Producers who suspect NWS should immediately contact their local veterinarian and state authorities. Early detection, strict livestock movement controls, screwworm fly suppression and rapid response are the best tools to combat this serious threat.

This detection marks the northernmost active case currently found in Mexico. It is also the second detection at the same Nuevo León feedlot since October. No additional cases were linked to the October detection, and both events appear tied to livestock movements from southern Mexico.

For more on NWS, including a current list of NWS detections within 400 miles of the U.S. visit Screwworm.gov .

Your Next Reads:
Next Step in the Screwworm Fight: USDA Announces Opening of Sterile Fly Dispersal Facility in Tampico, Mexico
The Smell You’ll Never Forget: A Calf Infested with New World Screwworm

USDA Launches Screwworm.gov

Fri, 21 Nov 2025 20:53:06 GMT

Today, the U.S. Department of Agriculture (USDA) launched the new nnified New World screwworm (NWS) website, screwworm.gov . This dynamic new site centralizes NWS information available across the federal government and reflects our whole-of-government effort to fight this pest through implementation of Secretary Rollins’ comprehensive five-pronged plan .

“The Trump Administration is leading a whole of government effort to protect our nation’s cattle industry from the New World Screwworm. To ensure timely and effective communications, this new unified website will be a one stop shop for all screwworm related information and will help our stakeholders be better informed as new information comes available,” Rollins says in a news release . “We are grateful for the robust interagency collaboration, and we continue to work every day with our state and industry partners to implement our screwworm plan. This is a national security priority and it has the full attention of our team.”

Screwworm.gov has targeted resources for a wide range of stakeholders including livestock producers, veterinarians, animal health officials, wildlife professionals, healthcare providers, pet owners, researchers, drug manufacturers and the general public. It also has the latest USDA-verified information on cases and response activities in Mexico and U.S. preparedness efforts.

NWS Update

In a press release Friday, APHIS shared an update on the battle against NWS. According to the release, USADA in close collaboration with its interagency partners and Mexico’s El Servicio Nacional de Sanidad, Inocuidad y Calidad Agroalimentaria (SENASICA), has made considerable progress in reducing the overall threat of NWS to U.S. agriculture and mitigating northern movement of the fly within Mexico.

As of Nov. 21, NWS has not been detected in any animals or traps in the U.S., and the vast majority of cases within Mexico remain concentrated in southern parts of the country. The Trump Administration remains steadfast in its resolve to safeguard America’s rural economy, domestic food supply, and public health from this invasive pest.

“USDA is actively investing in physical infrastructure to expand our capacity for sterile fly production and dispersal, while APHIS’ technical experts continue their intensive work across multiple programs and disciplines to further strengthen our strategic planning and domestic preparedness,” the press release says.

Cross-Border Response and Collaboration

In October, USDA conducted its most recent audit of NWS response activities in Mexico. Evaluators documented great progress in management of NWS, with robust outreach and education, effective emergency response and treatment protocols, and expansion of the workforce and surveillance. While there is still work to be done, USDA and SENASICA are committed to continued collaboration to implement the joint NWS action plan.

“In the event of case detection in a new (previously NWS-“Free”) location within Mexico, USDA teams are on the ground working alongside SENASICA counterparts to ensure treatment of affected animals, epidemiological tracing, local surveillance, and timely dispersal of sterile flies,” the release explains.

The two isolated NWS cases in cattle in Nuevo León were categorized as “inactive” by SENASICA last month, after the animals received antiparasitic treatment and completed 21-day quarantines. No additional NWS cases or non-sterile flies have been identified through intensive surveillance and trapping in Nuevo León or any other border State.

As a precaution, APHIS will continue to direct the release of sterile flies across these northernmost detection areas until December. On Nov. 11, an NWS case was detected in Guerrero State (502 miles from the U.S. border). As with the Nuevo León cases, USDA had a sterile fly dispersal plan in place within 12 hours of notification. As of Nov. 21, the active case closest to the U.S. is in central Veracruz State, around 425 miles from the border.

In early November, President Claudia Sheinbaum welcomed Secretary Rollins and her team to the Presidential Palace to discuss continued collaboration on shared challenges including NWS, and the Secretary attended a separate meeting with SENASICA to review bilateral response activities. USDA Under Secretary for Marketing and Regulatory Programs Dudley Hoskins accompanied Rollins on the trip and visited the State of Chiapas to review NWS containment practices and enforcement.

Protecting the Border and Maximizing Our Readiness

USDA personnel at the southern border continue to strengthen monitoring systems for NWS. APHIS has equipped counties along the southern border in Texas, Arizona, New Mexico and California with approximately 120 monitored NWS-specific fly traps and more than 7,000 fruit fly “double duty” traps. To date, more than 30,000 U.S.-trapped flies have been submitted for NWS analysis; as of Nov. 21, all flies have been confirmed to be negative. Meanwhile, APHIS Wildlife Services teams have examined at least 6,642 wild animals across 28 species in 120 U.S. counties, finding all to be free of NWS infestation.

“Should this pest enter the United States in the future, we have the tools, resources, and response plans in place to rapidly contain and eradicate it,” the release stresses.

Following the Oct. 17 release of the draft NWS Response Playbook , APHIS Veterinary Services has been actively collecting stakeholder feedback to ensure the playbook’s operational useability and alignment with State and Federal response capabilities. The playbook and accompanying materials are living, dynamic documents that will continue to be refined in the coming months; comments and suggestions may be submitted to fad.prep.comments@usda.gov .

Taking the Fight to NWS

The release says COPEG’s sterile NWS production facility in Pacora, Panama, is operating at maximum production capacity (approximately 100 million flies per week). Aerial dispersal of sterile flies has continued uninterrupted in NWS-affected areas of southern Mexico, where joint response activities with SENASICA are largely focused.

On Nov. 13, APHIS announced the opening of a new sterile insect dispersal center in Tampico (Tamaulipas State), allowing for aerial dispersal over the detection sites in Nuevo León and replacing the use of ground release chambers in that location.

“This investment represents an important step forward in the NWS response as it creates greater flexibility and predictability in our deployment of sterile insects across northern Mexico and along the border, if necessary,” according to the release.

Construction is progressing on the sterile fly dispersal facility at Moore Air Base in McAllen, Texas, and it is on track to be operational in early 2026. USDA also continues to work closely with the U.S. Army Corps of Engineers (USACE) on planning for the domestic production facility for sterile flies.

In early November, COPEG hosted a team of technical experts from USACE, who were able to observe the production process firsthand and learn about facility requirements.

USDA is in the process of finalizing details for the NWS Grand Challenge — up to $100 million of new funding to combat the pest and prevent its spread northward. We’re calling on innovators, researchers, and industry leaders to help us enhance sterile NWS fly production and strengthen preparedness. Potential projects might include: enhancement of sterile NWS fly production; development of novel NWS traps and lures; increased understanding of NWS therapeutics/treatments in animals; or other tools to bolster U.S. preparedness or response to NWS. Monitor screwworm.gov and the APHIS stakeholder registry for updates on this opportunity.

Your Next Reads: The Smell You’ll Never Forget: A Calf Infested with New World Screwworm

Next Step in the Screwworm Fight: USDA Announces Opening of Sterile Fly Dispersal Facility in Tampico, Mexico

Thu, 13 Nov 2025 19:31:40 GMT

USDA announced Thursday the opening of a sterile fly dispersal facility in Tampico, Mexico. The Tampico facility will allow USDA to disperse sterile flies aerially across northeastern Mexico, including in Nuevo Leon. This announcement is the next milestone in the fight against New World screwworm (NWS).

“The opening of the Tampico sterile fly dispersal facility is another incredibly important tool in our arsenal to stop the spread of screwworm. The facility will ensure flexibility and responsiveness in northern Mexico, giving us a greater ability to drop sterile flies and continue to push the pest south,” said U.S. Secretary of Agriculture Brooke Rollins in a press release . “Stopping the spread of screwworm is a top priority for the entire Trump administration.”

Last week Rollins met with Mexican President Claudia Sheinbaum and her counterpart Secretary Julio Berdegue on the joint response to NWS.

“We are boosting our efforts and completing a joint review of our screwworm operations in Mexico to ensure our protocols are being followed,” she says. “As we enter the winter months , we continue to prioritize the response in Mexico and the rest of our five-pronged plan to protect U.S. livestock and the livelihoods of American farmers and ranchers.”

A proven method for NWS eradication is releasing sterile male flies to mate with wild females collapsing the population over time. There are two methods of dispersing sterile insects – aerial dispersal and ground release chambers. Aerial operations are preferred because they allow for dispersal at a steady rate through a large area and also because sterile insects may be dispersed in areas that are unreachable from the ground. Ground release chambers are used when there’s a need to quickly deploy sterile insects outside of the dispersal facility range.

Learn more about NWS:
The Smell You’ll Never Forget: A Calf Infested with New World Screwworm

According to the press release, USDA continues to disperse 100 million sterile flies per week in Mexico, but until now, aerial operations have been limited to southern Mexico, necessitating the use of ground release chambers in more northern areas of the country. Mass production and targeted dispersal of sterile flies remain critical components of our effective response.

Although Mexico continues to confirm new cases of NWS, the overwhelming majority of these remain in the far southern part of the country, with no significant northward expansion over the past several months. Should that change, the Tampico facility will allow USDA to immediately tackle any cases that occur elsewhere in Mexico.

The two northernmost detections (approximately 70 and 170 miles from the U.S. border, respectively) occurred in Nuevo León, on Sept. 20 and Oct. 5 , in young cattle transported from Chiapas, Mexico.

Neither case is still active and there have been no additional detections of NWS flies in traps or cases in animals in Nuevo Leon. USDA continues to disperse sterile insects in Nuevo Leon, and will now transition from ground release chambers to aerial dispersal in those areas.

USDA produces sterile flies for dispersal at the COPEG facility in Panama. USDA is also investing $21 million to support Mexico’s renovation of an existing fruit fly facility in Metapa — which will double NWS production capacity once complete. With ongoing support from APHIS technical experts, Mexico anticipates this sterile fly production to begin as soon as summer 2026.

To expand our domestic response capacity, USDA has also begun construction on a sterile fly dispersal facility at Moore Air Base in Edinburg, Texas, that is projected to begin operating in early 2026. APHIS is also expediting design and construction of a sterile fly production facility in southern Texas, with a targeted maximum capacity of 300 million sterile flies per week.

USDA continues to work with Mexico’s agriculture authority, SENASICA, to implement the collaborative NWS Action Plan and guide trapping, surveillance and movement protocols to help stop the northward spread of NWS.

Trade Mission While In Mexico

While Rollins was in Mexico last week, she also led the largest U.S. Department of Agriculture agribusiness trade mission in history. During the mission, 41 U.S. businesses, 33 cooperators and agriculture advocacy groups, six state departments of agriculture, and 150 participants conducted more than 500 business-to-business meetings during the three days.

According to a USDA press release , “This was a critical opportunity for American business to further trade ties and for USDA to continue its aggressive response to NWS in Mexico and continue to hold Mexico accountable for its commitments to the 1944 Water Treaty.”

Honored to lead the largest @USDA Agribusiness Trade Mission in US history to Mexico City!

Over three days, our delegation of 41 US businesses, 33 cooperators, 6 state departments of agriculture, and 150 participants held more than 500 business-to-business meetings - deepening a… pic.twitter.com/39rGi9Snhj
— Secretary Brooke Rollins (@SecRollins) November 13, 2025

Your Next Read: Preparing for the Battle Continues: USDA Shares Screwworm Update and Releases NWS Playbook

Preparing for the Battle Continues: USDA Shares Screwworm Update and Releases NWS Playbook

Mon, 20 Oct 2025 16:57:26 GMT

U.S. Secretary of Agriculture Brooke Rollins shared a New World screwworm update on X Sunday night.

“First and most important — No new cases have been detected in the last seven days in Mexican states bordering the United States,” Rollins says. “USDA and our partners continue to lead an aggressive response to New World screwworm (NWS). This is a national security threat, and it has the full attention of the Trump administration.”

Updates Rollins shared included:

Dispersing 100 million sterile flies per week in Mexico produced at the COPEG facility with more than 40 dispersal flights throughout Southern Mexico per week.
“USDA closely monitors the locations of detections in Mexico and ensures shipments of sterile insects and release chambers are routed to the locations of the latest detections for dispersal,” she says.
Inspecting wild or feral animals for NWS infestation as part of wildlife management activities in Texas, with more than 1,670 animals inspected to date.
Working with Mexico on trapping and surveillance.
“USDA staff have confirmed 7,885 total confirmed NWS cases in southern Mexico, an increase of 838 cases since Oct. 2,” Rollins reports. “There have been zero detections in border states since Oct. 5.”
Construction update: The NWS Sterile Fly Dispersal Facility at Moore Air Base will open in early 2026. This facility will allow USDA to disperse 300 million sterile flies weekly at the border and in northern Mexico.

NWS Playbook Released

Rollins says on Friday USDA hosted a call with more than 200 state partners and stakeholders to release the new USDA NWS Response Playbook .

“This playbook reflects our current approach and response if we ever have a confirmed positive NWS in the USA,” Rollins explains. “We want our state and industry partners to continue to provide feedback on ways to make the playbook even stronger.”

Industry stakeholders can provide feedback and suggestions regarding the playbook to FAD.PReP.Comments@usda.gov.

🚨 𝐍𝐖𝐒 𝐔𝐏𝐃𝐀𝐓𝐄 🚨

FIRST and most important — No new cases have been detected in the last 7 days in Mexican states bordering the United States.@USDA and our partners continue to lead an aggressive response to New World Screwworm (NWS). This is a national security threat…
— Secretary Brooke Rollins (@SecRollins) October 20, 2025

Playbook Highlights

According the playbook, the phases of the response include:

Preparedness — planning, organizing, training, equipping, exercising, evaluating and taking corrective action to ensure effective coordination during an outbreak response.
Confirmation, or NWS establishment in the U.S. due to NWS myiasis in warm-blooded animals or detection of NWS fly.
Containment, or preventing the spread of NWS in early stages of infestation through measures such as early detection, quarantines and movement requirements, sterile insect technique (SIT) and surveillance to reduce spread in domestic animals and wildlife.
Mitigation, or minimizing the outbreak impact, by reducing the geographic extent of the affected area to reduce strain on resources, achieved largely through quarantines and movement requirements, SIT and surveillance, and constant evaluation of impacted areas.
Control, or demonstrating infestation is being mitigated based on epidemiology and surveillance.
Eradication, or demonstrating freedom from NWS in previously affected areas.

If NWS is found in the U.S., USDA APHIS Veterinary Services will provide guidance, support, resources and coordination during an outbreak. The approaches and tools included in the playbook reflect USDA APHIS guidance and aim to provide a practical framework to rapidly focus on priority activities. Tools and resources will be updated regularly as new guidance on NWS is released.

Managing an NWS Response: Key Activities

(USDA APHIS)

The playbook includes eight key response activities:

Effectively manage a coordinated response and communications with stakeholders and the public
Reduce spread to non-infested animals and prevent NWS from establishing in new areas
Manage NWS on infested premises
Implement NWS surveillance and management strategies in wildlife
Implement NWS fly surveillance and management strategies
Maintain continuity of business (COB)
Ensure information flow and management
Identify and maintain resource requirements

To learn more about the playbook, visit the New World Screwworm Emergency Response website.

Your Next Read: Winter: The Secret to Slowing the Spread of Screwworm

The Importance of Wildlife Monitoring for New World Screwworm

Mon, 06 Oct 2025 14:11:19 GMT

The New World screwworm (NWS) is a pest that no producer or veterinarian wants to see on a farm or ranch. However, with the recent active case identified just 70 miles south of the U.S.-Mexico border , it seems only a matter of time before this threat becomes reality.

While NWS is a threat to livestock operations, we must also consider the impact it could have on local wildlife. During the last outbreak of 2016-2017 in the Florida Keys, 136 wildlife cases were confirmed, and 15% of endangered Key Deer died. Along with concerns for wildlife health, wildlife monitoring has become an important tool for following the migration of these flies.

“Wildlife are a cherished natural resource and play vital roles in our ecosystem health,” says Dr. Marcus Blum, AgriLife Extension statewide specialist and assistant professor at Texas A&M. “Texas is home to more than 100 mammal species that are at risk if the fly re-establishes itself here.”

Screwworm Fly Migration

Most adult screwworm flies fly less than 10 miles searching for a host to lay their eggs in. While this natural migration is certainly affecting the spread of the pest, most of its travel is on infested animals.

“Most screwworm migration does not come from adult flies making heroic flights northward. Instead, it comes from the movement of infested animals — cattle, deer, wildlife — and yes, even in rare cases, people. Wherever the animal goes, the parasite goes with them,” said Dr. Christopher Lee on a recent episode of “Vet Watch”.

One of the biggest challenges with wildlife monitoring is that most free-ranging wildlife avoid human contact. Because of this, NWS infestations can go undetected — meaning large scale mortalities are possible.

Here are some things you can look for in wildlife you may observe:

Open sores and tissue damage on living wildlife. Maggots may be visible in wounds
Foul odor like rotting flesh
Strange behavior including head shaking, irritability, apparent discomfort, lethargy or isolation from other animals

Wildlife Affected by New World Screwworm

Chief among affected species are the more than 5 million white-tailed deer that call Texas home. White-tailed deer are highly susceptible and often show visible infestations in the head and neck areas. Since the last major NWS infestation in the 1960s, the Texas white-tailed deer population has grown from 500,000 to approximately 5.5 million in 2024. This increase in population also represents an increase in risk for NWS migration, as they are such good hosts for the pest.

Feral swine could also act as NWS carriers as their widespread presence and constant movement means they could spread infestations quickly. For cattle producers, this means that even if your herd is secure and well-maintained, an outbreak in nearby wildlife could easily spread onto your animals.

Wildlife susceptibility to NWS infestations varies by sex and season. This is due to seasonal behavior and environment changes.

How environmental temperatures impact fly activity and the alignment of this activity with season deer behaviors.

(Texas A&M Agrilife Extension)

NWS activity is at its highest in the summer when temperatures range from 70°F to 90°F. Unfortunately, this timing coincides with fawning season. Not only is the umbilical region of newborn animals highly susceptible to infestation, but NWS may also lay eggs on the mucous membrane of the genitalia.

In breeding season, male wildlife compete for mating dominance, often leading to wounds from fighting. These wound sites are the perfect place for NWS to lay their eggs.

Antler growth, antler shedding and velvet shedding also create opportunities for NWS infestation. For example, the Florida Keys outbreak occurred during rut season, and males had the highest mortality rates in Key deer.

How can you help monitor wildlfe?

Everyone who works the land or spends time outdoors can play a part in protecting against NWS. Ranchers, hunters and community members are often the first to spot unusual wounds on deer, feral hogs or other wildlife. If you’re using trail cameras, consider checking them regularly for any signs of wounded or abnormal appearing wildlife. A hunting stand can be a great vantage point for identifying infected animals. In more residential areas, security camera footage could be useful for monitoring wildlife. Also pay attention to scavengers. If you see vultures circling, investigate what is attracting them.

As always, do not attempt to approach live wildlife. Maintain a reasonable viewing distance for your own safety. If you suspect NWS in any wildlife you observe, including the observation of maggots, immediately report your sighting to your state animal health official and Animal and Plant Health Inspection Service (APHIS) office .

The battle against NWS isn’t just about livestock — it’s about the ecosystem around them. Wildlife can serve as both an early warning system and a pathway for infestations to spread. By recognizing the importance of wildlife monitoring, producers and veterinarians strengthen the shield that keeps herds and geographical regions safe from this destructive parasite.

Blum and colleagues have released a very informative fact sheet if you’re looking to learn more about wildlife monitoring and management for NWS.

Your Next Read: Winter: The Secret to Slowing the Spread of Screwworm

Winter: The Secret to Slowing the Spread of Screwworm

Thu, 02 Oct 2025 11:03:28 GMT

Winter or colder temperatures — it’s not something you typically hear livestock producers anticipating or praying for. But this year, as the threat of New World screwworm continues to inch closer to the U.S.-Mexico border, winter can’t come soon enough.

“Certainly, winter will be our friend,” says Chris Womack, a veterinarian and rancher from San Angelo, Texas. “Historically the flies were pushed south with frost.”

USDA Agricultural Research Service entomologist Kim Lohmeyer agrees we need winter to come fast. Lohmeyer serves as the laboratory director of the Knipling-Bushland U.S. Livestock Insects Research Laboratory in Kerrville, Texas, where she and her colleagues use modeling to know when and where NWS may show up in the U.S. They are partnering with Lee Cohnstaedt and his team at the National Bio and Agro-Defense Facility in Manhattan, Kan., to study the life stages of NWS and its susceptibility to temperature and weather.

“With the climate changes and weather patterns we have now, if this fly gets here, it can go a lot further north, a lot further east and a lot further west,” Lohmeyer says. “It’s something to keep an eye on.“

The Winter Win

So, what exactly does “winter” mean? Lohmeyer says NWS are fairly cold sensitive, so several days of sustained cold temperatures in around 30°F would be enough to suppress NWS.

The NWS’s ability to survive is restricted to locations where low temperatures are regularly above freezing. Ideal adult fly activity occurs at 77°F to 86°F and relative humidity of 30% to 70%.

“This fly really loves 81.5°F,” explains meteorologist Matt Makens. “The research shows that’s when they’re friskiest.”

Although the Sterile Insect Technique (SIT) remains a primary control mechanism, Makens says studies have made it clear that eradication success, outbreak intensity and re-emergence potential are closely tied to weather and climate.

“From seasonal wind patterns to monsoonal moisture, numerous environmental conditions shape the life cycle, spread and population dynamics of this parasite,” Makens explains. “Understanding these weather-related drivers is critical not only for control, but also in considering how long-term temperature trends have altered the geographic boundaries of screwworm viability since the major outbreaks of the 1950s and early 1960s.”

During a recent Cattlemen’s Call podcast Makens said weather is one of the main forces of spreading NWS.

“If we could control the weather, we could control the fly,” he stresses.

(Maps: Makens Weather)

Research indicates larval and pupal development cannot proceed below approximately 58°F and halts above 110°F. The optimal temperature for adult survival and reproduction lies around 81.5°F, a range common in tropical and subtropical climates like Mexico and Central America. NWS do not survive in regions with cold winters, though they may spread into these areas during the warmer months.

Impact of temperature on NWS:

Reduced activity: Adult screwworm fly activity is limited when temperatures are below 59°F.
Larval vulnerability: Pupae are vulnerable to soil temperatures below 46°F. Sustained maximums hotter than 95°F can also be limiting — extreme heat reduces adult fly activity and increases mortality in larvae exposed to hot surface soils.
Life cycle: While the entire life cycle can be completed in warm conditions, it takes longer in cooler, more temperate environments.

“One of the secrets to historically, the northern limit of screwworm, was basically a matter of how cold the winter got. That sort of limited how far it got,” says Derrell Peel, Oklahoma State University Extension livestock marketing specialist. “In years when it was warmer, it would go farther. It would overwinter farther north, but in general, that’s going to set the upper limit, or at least it does if it’s not under control in any other way. That will limit its northward, northern movement, for sure.”

1972 NWS data (A) Monthly maps of observed cases of myiasis in Texas during the 1972 outbreak. Highest abundance occurred in August, and the length of all other density colour bars were scaled to it (bars in right hand margin of each map). The maximum density is at the top of each colour bar with the highest midseason incidence occurring in south central Texas. (B) Histogram summarizing the monthly total statewide data. (C) Map of total cases of myiasis during 1972.

(Medical and Veterinary Entomology)

Fly Season

David Anderson, Texas A&M professor and Extension specialist, says, historically, the fly season is April to October.

“If we get a really cold winter, that helps us,” Anderson adds. “It buys us some more time. But things are warmer now than it used to be. Fly season may not be that April to October anymore.”

NWS’s typical life cycle lasts about 21 days in warm weather and slightly longer in cooler climates. According to Texas A&M AgriLife Extension Service, NWS fly life cycle is highly sensitive to temperature:

In warm (more than 80ᴼF daytime highs) and tropical conditions, the full life cycle may be complete in two to three weeks.
In more temperate conditions, the life cycle may take three to four weeks.
In cooler conditions, the life cycle may take up to two to three months.

It is important to understand that the flies do not die at these lower activity temperatures, but prolonged exposure to these temperatures can reduce populations or active infestations.

Texas rancher Wayne Cockrell says NWS’s entry into the U.S. is inevitable but suggests winter and colder weather might temporarily delay the spread until next April or May. Cockrell serves as the Southwestern Cattle Raisers Association director and chair of the cattle health and well-being policy committee.

“We should be within 60 days hopefully when cold weather helps in two-thirds of the state,” Cockrell explains.

Rainfall and Monsoon Factors

Makens says while temperature defines where screwworms can survive, rainfall and moisture influence when and how intensely they can thrive. Outbreaks often follow moderate to heavy rainfall by improving conditions for larval survival.

He explains tools like the Palmer Crop Moisture Index (CMI) have shown promise in predicting screwworm risk, with higher-than-normal CMI values sometimes preceding population spikes.

When rainfall coincides with favorable temperatures, screwworm activity tends to increase. In contrast, hot and dry conditions tend to suppress survival and reproduction.

“One of the most striking climate connections is the role of seasonal monsoon winds in transporting screwworms over long distances,” Makens explains. “In multiple outbreak years, adult flies were documented migrating northward into Texas and the desert Southwest via the North American Monsoon (NAM) — a seasonal pattern that delivers moisture to northwestern Mexico and the U.S. Southwest from June through September. During the summer, prevailing winds shift from west to a more humid, southerly flow, creating favorable conditions for fly migration from central and southern Mexico into their northern states and, at times, into the southern U.S. The NAM this year had an early start and gave significant rainfall to parts of Arizona and New Mexico. The NAM typically calms by early fall.”

In the 1960s, these wind-assisted movements allowed the temporary re-establishment of breeding populations even after local eradication. In some years, migration spanned hundreds of miles, connecting source populations in northern Mexico to re-infestations in Arizona and New Mexico.

“This atmospheric ‘conveyor belt’ remains a critical concern in surveillance strategies for livestock-producing regions of the Southwest,” Makens says. “The 2025 monsoon was undoubtedly a factor in the most recent northward migration of NWS.”

If NWS should cross the border, it will be key for producers to coordinate management practices with weather patterns expected for their region.

“Ultimately, weather patterns act as both a barrier and bridge for screwworm activity,” Makens summarizes. “Knowing how and when the balance tips is essential to preventing the return of one of the industry’s most damaging parasites.”

Here’s to hoping Old Man Winter decides to arrive quickly and help buy livestock producers and government leaders more time to prepare to battle NWS.

Your Next Read: The Battle at the Border

New Technology to Combat New World Screwworm

Tue, 30 Sep 2025 10:31:12 GMT

The U.S. Department of Energy’s National Nuclear Security Administration’s (NNSA) Office of Radiological Security (ORS) is partnering with Texas A&M University to combat New World screwworm (NWS) .

On Sept. 21, USDA announced NWS had been found less than 70 miles from the U.S. border near one of the most heavily trafficked commercial thoroughfares in the world.

Working with Texas A&M’s National Center for Electron Beam Research (NCEBR), NNSA is advancing the Sterile Insect Technique (SIT) using electron beam (eBeam) technology in place of radioactive cobalt. SIT effectively prevents the spread of NWS by releasing sterilized male screwworms to halt reproduction and reduce their population.

According to the release, ORS’s mission includes preventing the misuse of highly radioactive materials and promoting innovative alternatives like eBeam devices. The eBeam technology eliminates the need for radioactive sources, which could be used for nefarious purposes if they fell into the wrong hands.

This collaboration enhances radiological security best practices nationwide, thus strengthening national security.

“Our mission-driven partnership with Texas A&M is essential to advancing American innovation in eBeam applications and enhancing our national security,” says Kristin Hirsch, Director of ORS. “With the support of Texas A&M AgriLife experts, NNSA is able to help combat the spread of the NWS, building stronger food systems and safer communities across the country.”

U.S. Secretary of Agriculture Brooke Rollins recently announced a new NWS fly dispersal facility in Texas and a five-pronged plan for eradicating the pest. The plan includes the USDA pursuing innovative research, such as eBeam and other technologies.

Currently, SIT relies on cobalt-60 gamma sterilization. But cobalt-60 carries significant radiological security risks, so NNSA, NCEBR and Texas A&M’s Department of Entomology have worked to find replacement methods. Through modeling studies sponsored by NNSA and conducted by Texas A&M since 2023, researchers identified eBeam technology as a viable alternative and are working to make it available to USDA to combat NWS.

The eBeam system at work, sterilizing screwworm pupae. This technology is vital for protecting U.S. agriculture and radiological security.

(U.S. Department of Energy NNSA)

NNSA has been collaborating on the development of an eBeam system to be used for chemical remediation, another critical area where cobalt-60 use could become a risk. NNSA is repurposing this technology toward NWS response and accelerating development to make eBeam available to USDA by early 2026.

Once integrated into a rearing facility, it could create more than 100 million sterile flies in 24 hours. That’s a vast improvement compared to cobalt-60, which can take a week to do the same amount. This efficiency would be a game-changer in NWS response.

Your Next Read: The Battle at the Border

U.S.-Mexico Border Battle Continues As the Threat of New World Screwworm Intensifies

Wed, 24 Sep 2025 20:04:06 GMT

With New World screwworm (NWS) confirmed just 70 miles from the U.S. border , producers, government officials and industry leaders are taking action. Finding NWS along one of the most heavily trafficked commercial thoroughfares in the world from Monterrey, Nuevo Leon, to Laredo, Texas, is a red flag for the industry. Emphasizing the importance of maintaining strong safeguards, it’s time to plan for not “if but when” NWS crosses the border.

On Monday, Secretary of Agriculture Brooke Rollins confirmed protecting the U.S. from NWS is non-negotiable and a top priority for President Trump.

UPDATE ON SCREWWORM THREAT:

Protecting the United States from New World Screwworm is non-negotiable and a top priority for @POTUS.@USDA landed boots on the ground this morning in Nuevo Leon, physically inspecting traps and dispersing sterile flies after the detection of the…
— Secretary Brooke Rollins (@SecRollins) September 23, 2025

“The southern border remains closed to livestock trade, and we are aggressively expanding trapping and surveillance,” she wrote. “At the same time, we’re expediting operations at our sterile fly dispersal facility at Moore Air Base in Texas .”

On Tuesday, Secretary of Agriculture Brooke Rollins reported 80,000 sterile flies were released on “spot” and nearly 200 surge staff had been deployed to Mexico.

Thank you, @IngrahamAngle, for paying attention to this important issue. Due to multiple failures from our southern neighbors and failure to act in the last Admin, the devastating parasite New World Screwworm is knocking on our southern borders door. We’re not waiting, we’re… pic.twitter.com/ZO5Vx5oes8
— Secretary Brooke Rollins (@SecRollins) September 24, 2025

Mexico’s Response To New World Screwworm

According to Reuters, Mexican’s agriculture ministry said there is no risk of adult screwworm fly emergence due to the early detection of the infected bovine, which was confirmed on Sept. 21. The infected animal was in a shipment of 100 animals originating from the Gulf Coast state of Veracruz, according to the statement.

Fly traps in northern Mexico have not detected a single screwworm fly.

U.S.-Mexico Border Remains Closed to Cattle Trade

The Mexican border closure remains a topic of debate. The September Ag Economists’ Monthly Monitor found 80% of ag economists surveyed oppose reopening the border to Mexican cattle due to screwworm risks.

(Farm Journal)

The border closure has created significant division within the cattle industry with producers, feeders and industry leaders on both sides of the fence.

“We have some cattle people that are glad it’s closed. We’ve got others who are hit pretty hard and are not happy about it,” explains David Anderson, Texas A&M professor and extension specialist — livestock and food product marketing.

NWS is a threat the industry can not ignore, says the ag economist with more than 30 years under his belt.

“I think this is the most serious problem the industry has faced since I’ve been a livestock economist,” he stresses.

From his perspective, keeping the border open with heightened monitoring and surveillance could have potentially been more effective than implementing a total closure.

“If we go back and look at data from the early ‘70s, when we had a big screwworm outbreak in the U.S. and Mexico, the border was open,” he says. “I probably would have leaned to not closing the border to begin with. I understand why you would want to do that, but I don’t know that it’s ended up reducing the likelihood that we’re going to get screwworms, and yet we’re paying a price for that.”

According to Anderson the economic consequences to the border being closed are:

Significant loss of approximately 26,000 imported cattle weekly
Estimated 18% reduction in cattle placements in Southern plains
Contributed to tighter beef supplies and higher consumer prices
Substantial economic hit to cattle feeders and ranchers

At this point, he’s quick to admit keeping the border closed is the best option.

When it comes to reopening the border, Derrell Peel, Extension livestock marketing specialist with Oklahoma State University, suggests the decision is not straightforward.

“Given everything I’ve experienced, it’s probably prudent to leave the border closed,” he says.

He adds any reopening should be “under very, very controlled, limited circumstances.”

Peel emphasizes the need for a collaborative approach with Mexico.

“We’re kind of in it together, and so whether it’s here or there, we’ve got to work together,” he summarizes. “We’re going to need to control it in both places. Otherwise, it’s not going to benefit either one of us.”

He also points out not everybody in Mexico is sorry the border is closed. For example, cattle buyers in Mexico can source cattle cheaper because the border is closed.

“Keeping the border closed does affect the movement of cattle south of the border ... it builds a backstop for cattle movement north,” he adds.

Peel notes cattle from Central America to Panama have increasingly made their way to the Mexican market, which validates NWS movement in Mexico and why recent confirmation has occurred.

“The longer this goes on, the more the Mexican industry will adjust,” he says. “It might permanently change the way the [U.S. and Mexico] work together.”

Texas Rancher Weighs In On Impact of New World Screwworm

Texas rancher Wayne Cockrell says the parasite’s entry into the U.S. is inevitable, suggesting that winter and colder weather might temporarily delay the spread until next April or May. Cockrell, who serves as the Southwestern Cattle Raisers Association director and chair of the cattle health and well-being policy committee, recently joined AgriTalk to talk about NWS.

“We would much rather stop this on Mexico’s southern border than our Southern border,” Cockrell says.

Mexican feeder cattle traditionally represented 30% of Texas feedyard inventory, he adds, but with current restrictions, feedlots are adapting.

“I think a lot of those feedyards have moved to the dairy-cross side,” he adds. “They have had to change the way they do business.”

Noting the broader economic implications of the border closure, 1.2 million fewer cattle for Texas represents “about two weeks” of impact nationwide, according to Cockrell.

“Winter and sterile flies is what we need now,” Cockrell summarizes.

Your Next Read: The Smell You’ll Never Forget: A Calf Infested with New World Screwworm

Mexico Confirms Case of New World Screwworm 70 Miles from U.S. Border

Mon, 22 Sep 2025 03:46:51 GMT

Mexico’s National Service of Agro-Alimentary Health, Safety, and Quality (SENASICA) confirmed a new case of New World screwworm (NWS) in Sabinas Hidalgo, located in the state of Nuevo León, less than 70 miles from the U.S.-Mexico border on Sept. 21.

USDA reports this is now the northernmost detection of NWS during this outbreak, and the one most threatening to the American cattle and livestock industry. Sabinas Hidalgo is located near one of the most heavily trafficked commercial thoroughfares in the world, the major highway from Monterrey, Nuevo Leon, to Laredo, Texas.

“Protecting the United States from NWS is non-negotiable and a top priority of the Trump Administration,” U.S. Secretary of Agriculture Brooke L. Rollins said in a release . “This is a national security priority. We have given Mexico every opportunity and every resource necessary to counter NWS since announcing the NWS Bold Plan in June 2025.”

Rollins says the U.S. will not rely on Mexico to defend U.S. agriculture.

“We are firmly executing our five-pronged plan and will take decisive action to protect our borders, even in the absence of cooperation,” Rollins said. “Furthermore, we will pursue aggressive measures against anyone who harms American livestock.”

The previous northernmost detection was reported approximately 370 miles farther south on July 9 in Veracruz, USDA reports.

SENASICA preliminary reports indicate the affected animal — an 8-month-old cow — had recently been moved to a certified feedlot in Nuevo León from a region in southern Mexico with known active NWS cases. USDA says this potential link to animal movement underscores the “non-negotiable need for Mexico to fully implement and comply with the U.S.–Mexico Joint Action Plan for NWS in Mexico.” U.S. ports remain closed currently to imports of cattle, bison, and horses from Mexico.

USDA has been actively monitoring nearly 8,000 traps across Texas, Arizona and New Mexico. More than 13,000 screening samples have been submitted to date, with no NWS flies detected. USDA said it will continue to analyze all new information related to the recent case in Nuevo León and will pursue all options to release sterile flies in this region as necessary.

As well, USDA will release a significant plan soon to help rebuild the American cattle supply, incentivizing ranchers and driving a full-scale revitalization of the American beef industry, the release said.

USDA Leads An Aggressive National Response
USDA reports it’s comprehensive strategy includes the following immediate actions:

Innovating Our Way to Eradication
USDA is investing $100 million in breakthrough technologies through the NWS Grand Challenge. This program will solicit ideas to enhance sterile fly production and develop new tools such as advanced traps, lures and therapeutics. USDA says it’s also exploring and validating technologies like e-beam and x-ray sterilization, genetically engineered flies, and modular sterilization facilities through public listening sessions and ongoing evaluations.
Protecting the U.S. Border
USDA has begun construction on a domestic sterile fly dispersal facility at Moore Air Force Base in Edinburg, Texas. This $8.5 million facility, expected to be mostly complete by the end of 2025, will be capable of dispersing up to 100 million sterile flies per week, USDA says. The U.S. Army Corps of Engineers is working with USDA on plans for for construction of a domestic sterile fly production facility in Southern Texas, with a projected capacity of 300 million sterile flies per week.
Strengthening Surveillance and Detection
USDA has been actively monitoring nearly 8,000 traps across Texas, Arizona and New Mexico since July. To date, more than 13,000 screening samples have been submitted, with no NWS flies detected. USDA continues to disperse 100 million sterile flies per week in Mexico, sourced from the COPEG facility in Panama. In addition, USDA is providing support to Mexico to renovate a production facility in Metapa, which is expected to produce an additional 60–100 million sterile flies.
Enhancing Public Awareness and Education
APHIS has published an updated national disease response strategy and is providing training and webinars for federal, state, Tribal and veterinary partners. Outreach materials, including pest ID cards and alerts, are being distributed along the U.S.–Mexico border. APHIS has held over 50 stakeholder meetings and continues to expand outreach efforts.
Coordinating with Mexico and International Partners
Following detections in Oaxaca and Veracruz, USDA closed southern ports of entry to livestock trade after a case was reported 370 miles from the U.S. border. USDA is conducting monthly audits of Mexico’s NWS response and is helping the country develop a more risk-based trapping plan, especially in Veracruz and along the border. Mexico currently deploys traps in high-risk areas, with USDA support.

USDA is supporting hiring of over 200 surge staff for trapping and animal movement control in Mexico. As well, SENASICA has launched a dashboard that tracks NWS cases across Mexico. This enhances USDA’s ability to monitor the situation south of the border, better assess risk, and deliver more effective operational responses in coordination with Mexican authorities.
Unprecedented Interagency Collaboration
Collaborating agencies include: Centers for Disease Control and Prevention, Food and Drug Administration, Department of the Interior, Department of Energy, Department of Homeland Security, Environmental Protection Agency, and the Department of State. This collaboration is guided by the U.S. One Health Coordination Unit for NWS (U.S. OHCU–NWS), co-led by USDA, CDC, and DOI, the release said.

Watch Out for Signs of NWS
NWS maggots most often enter an animal through an open wound and feed on the animal’s living flesh. They can infest livestock and other warm-blooded animals, including people.

USDA urges residents on the southern border to check their pets and livestock for signs of NWS .

“Look for draining or enlarging wounds and signs of discomfort,” USDA said. “Also look for screwworm larvae (maggots) and eggs in or around body openings, such as the nose, ears, and genitalia or the navel of newborn animals. If you suspect your animal is infected with screwworm, contact your state animal health official or USDA area veterinarian immediately.”

Although not common in people, if you notice a suspicious lesion on your body or suspect you may have contracted screwworm, seek immediate medical attention.

New World Screwworm Numbers Increasing in Mexico

Thu, 28 Aug 2025 16:20:52 GMT

Cases of New World Screwworm continue to increase in Mexico. According to Reuters , Mexico has recorded 5,086 cases of flesh-eating screwworm in animals as of Aug. 17, a 53% jump from the number of cases reported in July. The Reuters refers to data from the Mexican government.

The updated numbers, which have not been previously reported to the public, showed 649 currently active cases.

“That’s absolutely concerning,” says Neal Wilkins, CEO of conservation and cattle group East Foundation. “Having a 50% increase in month-over-month numbers, particularly in the extreme heat, means they haven’t gotten it under control.”

According to a spokesperson for the National Cattlemen’s Beef Association: “The increase of cases reported in Mexico shows that New World screwworm is still a very present threat. We need to continue full steam ahead with all possible prevention and mitigation tools. This includes the funding that Secretary Rollins has announced for a domestic sterile fly facility , coupled with increased surveillance and screening measures.”

The increase in reported cases in Mexico can be attributed to Mexican cattle producers inspecting their cattle and reporting any suspicious wounds or insects.

“This is the right thing to do, and it’s important for everyone to remain vigilant,” the NCBA spokesperson confirms. “We also need to keep in mind that New World screwworm is a multispecies disease, and currently there is limited information on wildlife infestations in Mexico. Beyond cattle and domestic livestock, Mexican authorities must also develop a multispecies response that addresses the risk from wildlife.”

The majority of cases were identified in cattle, though Mexican government data also showed infestations in dogs, horses and sheep. According to the COPEG (Panama–United States Commission for the Eradication and Prevention of Screwworm Infestation in Livestock) website , reported cases have been 85% bovine, 6% canine, 3% swine, 3% equine and 2% sheep.

On July 8, Mexico’s National Service of Agro-Alimentary Health, Safety and Quality reported a NWS case in Ixhuatlan de Madero, Veracruz, Mexico, which is approximately 370 miles south of the U.S./Mexico border. This northward detection came approximately two months after northern detections were reported in Oaxaca and Veracruz, less than 700 miles away from the U.S. border.

Your Next Reads:
The Smell You’ll Never Forget: A Calf Infested with New World Screwworm

Human Case of New World Screwworm Confirmed in Maryland

Breaking News: USDA to Invest $750 Million to Build a Domestic Sterile Fly Production Facility

Human Case of New World Screwworm Confirmed in Maryland

Mon, 25 Aug 2025 02:13:42 GMT

The U.S. Department of Health and Human Services on Sunday reported a human New World screwworm (NWS) case.

The case, investigated by the Maryland Department of Health and the U.S. Centers for Disease Control and Prevention, was confirmed by the U.S. Centers for Disease Control and Prevention (CDC) on Aug. 4, and involved a patient who returned from travel to El Salvador, HHS spokesman Andrew G. Nixon said in an email to Reuters.

Gabriel Alvarado, CDC spokesperson, confirms the email saying, “CDC, in coordination with the Maryland Department of Health, investigated a confirmed case of travel-associated New World screwworm in a patient who returned from travel to El Salvador. The case was confirmed by CDC through telediagnosis (i.e., expert review of submitted larvae images) on Aug. 4, 2025.”

In response to the confirmation, USDA shared a statement : “In support of CDC’s activities and out of an abundance of caution, USDA initiated targeted surveillance for NWS within a 20-mile radius of the affected area, encompassing portions of the District of Columbia, Maryland, and Virginia. To date, all trap results have been negative for NWS. There have been no detections of NWS in the U.S. in livestock or other animals since the last outbreak of NWS in the Florida Keys was resolved in 2017.”

Reuters reported on Sunday evening that a person who had traveled to the U.S. from Guatemala was confirmed as receiving treatment in Maryland for NWS.

“The risk to public health in the United States from this introduction is very low,” Nixon said.

State veterinarians learned of the human case during a call last week with the CDC.

The exact dates of travel and arrival in U.S. are not confirmed at this time.

South Dakota State Veterinarian Beth Thompson, who was quoted in the story, says when CDC officials confirmed it was NWS, CDC worked with local physicians and dealt with the larva. She says there has been no livestock movement control put into place because of the case.

Thompson says NWS is endemic in some Central American countries.

This is not the first case of a U.S. traveler being infect with NWS. According to a CDC Resurgence of NWS Update webinar :

In 2014, a woman in her mid-20s returned from a beachside resort in the Dominican Republic where she fell asleep on the beach one night. Pain started in her ear the next day and it was discovered she had NWS when she got back to the U.S.
In 2023, a mid-60s male traveled to Argentina and Brazil with a fresh surgical wound on his cheek. NWS entered through his wound and he received treatment for larvae infestation once he returned to the U.S.
In 2024, an individual spent approximately seven days in the Dominican Republic. This individual was immunosuppressed due to a previous case of cancer in their nose. Once the individual arrived back in the U.S., 100 to 150 larvae were surgically removed from their nose.

Two other cases include a 15-year-old girl when she returned from a three-week hiking trip to Peru and a 12-year-old girl who had been on a church mission to Palmira, Colombia .

USDA also confirmed it was not the first case saying, “There have been previous instances of traveler-associated cases of NWS in the United States in years past. In all cases, these instances were isolated and designated as closed after precautionary targeted surveillance in the vicinity was negative. We may continue to see traveler-associated cases of NWS and USDA, in coordination with HHS and CDC, will conduct targeted surveillance to ensure there is no active spread of NWS in the United States. This is not cause for alarm as human risk is low and we have seen several isolated cases in recent years that have not resulted in livestock transmission.”

National Cattlemen’s Beef Association CEO Colin Woodall, says, “NCBA is aware of a New World screwworm case detected in a person traveling from abroad into Maryland. The case was quickly identified and handled by the CDC in accordance with their protocols. Based on what has been shared with state animal health officials, we do not see any elevated risk to the livestock industry at this time. We appreciate the diligence of human health authorities. This case was quickly addressed thanks to existing protocols, and we are thankful for the ongoing coordination between the CDC, state departments of health, state animal health officials, and USDA.”

As more details are available, we will update this story.

Your Next Reads:

Emergency Use of Animal Drugs Approved to Combat New World Screwworm

Tue, 19 Aug 2025 16:09:22 GMT

The U.S. Department of Health and Human Services (HHS) issued a declaration on Aug. 19 allowing the U.S. Food and Drug Administration (FDA) to issue Emergency Use Authorizations (EUAs) for animal drugs to treat or prevent infestations caused by the New World screwworm (NWS).

This declaration applies only to drugs for animals. NWS infests warm-blooded animals, including livestock, pets, wildlife, and, in rare cases, humans, causing severe tissue damage and sometimes death. The risk to human health in the U.S. remains very low, but the potential future threat to animal populations and the food supply chain requires proactive action.

Although eradicated from North America and Central America decades ago, NWS has progressed north since 2022 and is now approaching the U.S. border with Mexico. This parasite poses an emerging threat to livestock and food security, with potential impacts on both national security and animal health.

“Today we are taking decisive action to safeguard the nation’s food supply from this emerging threat,” says HHS Secretary Robert F. Kennedy, Jr. “This authorization equips FDA to act quickly, limit the spread of New World Screwworm, and protect America’s livestock.”

Currently, there are no FDA-approved drugs for NWS in the U.S. The FDA through an EUA can authorize the flexible, faster use of certain animal drug products that may be approved for other purposes, or available in other countries, but not formally approved for NWS in the U.S. This ensures veterinarians, farmers, and animal health officials have timely access to the tools they need to protect pets, livestock and the nation’s food supply.

“Thank you to my friends and partners Secretary Kennedy and Commissioner Makary who are answering the call and supporting our aggressive plan to push back and ultimately defeat this devastating pest. This emergency use authorization is another tool we can use in the fight against New World Screwworm,” says Secretary of Agriculture Brooke L. Rollins. “Our cattle ranchers and livestock producers are relying on the Trump Administration to defend their livelihoods. Stopping this pest is a national security priority and we are linking arms across President Trump’s cabinet to defend our borders and push back this threat.”

FDA Commissioner Marty Makary, M.D., M.P.H., adds, “Our priority is to safeguard both animal health and the nation’s food supply. FDA is acting swiftly and responsibly to help ensure we have the necessary tools to prevent and control New World Screwworm, minimizing risks to agriculture and public health.”

FDA will provide future guidance to veterinarians and stakeholders on the appropriate use of any products authorized for emergency use and update the New World Screwworm: Information for Veterinarians page.

Breaking News: USDA to Invest $750 Million to Build a Domestic Sterile Fly Production Facility

Fri, 15 Aug 2025 17:57:11 GMT

Today in Austin, Texas, U.S. Secretary of Agriculture Brooke Rollins and Texas Gov. Greg Abbott hosted a press conference announcing new strategies to stop the spread New World screwworm .

“We will continue to take all necessary steps across the entirety of the federal government, working alongside our partners at the state government, and in the local governments, to ensure that we keep this pest — this parasite, and others like it — out of our country that threaten our economy and our way of life,” Rollins says.

I’m in Texas today as we continue to aggressively address the serious New World Screwworm threat endangering our American livestock industry and our nation’s national security. @USDA is announcing a historic investment to STOP screwworm in its tracks — with 5 pillars of action:… pic.twitter.com/ukcWSSamcZ
— Secretary Brooke Rollins (@SecRollins) August 15, 2025

Rollins shared five pillars of action to help keep NWS out of Texas and the U.S.:

1. Innovate to Eradicate — Investment in new tech, traps and treatments
Rollins plans to allocate up to $100 million to develop cutting-edge technologies to accelerate the country’s response.

While sterile flies are currently the most effective way to prevent the spread of NWS, technology continues to evolve and as such USDA will provide up to $100 million to invest in viable innovations which could show rapid advancement of promising technologies that will augment the U.S. facility and accelerate the pace of sterile fly production if proven successful.

USDA will support proven concepts that only require funding to scale and implement as well as a number of longer-term research projects focused on: new sterile NWS production techniques, novel NWS traps and lures, NWS therapeutics that could be stockpiled and used should NWS reach the U.S., and any other tools to bolster preparedness or response to NWS.

“I’m calling on the brightest minds in the country to build on our existing tools and help us outpace this pest quickly and in the most innovative way possible,” Rollins says.

2. Build Domestic Production
She announced the plan to invest $750 million to build a domestic sterile fly production facility in Edinburg, Texas, which will be capable of producing 300 million sterile screwworm flies per week. This facility will be located 20 miles from the southern border and near the Moore Air Base in Texas.

Once complete, the facility will triple current fly output and reduce reliance on Panama and Mexico for sterile fly production. Rollins says it will also create 300 jobs in Texas.

Prior to this announcement, the USDA committed Moore Airfield Base as a dispersal facility for sterile NWS flies, which was to be completed at the end of the year. While NWS can be treated, the only proven method for eradication is releasing sterile male flies to mate with wild females collapsing the population over time.

The only sterile fly facility in the world is COPEG in Pacora, Panamá which is currently operating at full capacity, producing 115 million flies per week. The U.S. owned a facility in Chiapas during the NWS outbreak in the 1960s but it has since been closed.

1 of 3:

Leaders of NCBA and TSCRA attend New World screwworm briefing in Texas.

TSCRA

2 of 3:

Leaders of NCBA and TSCRA attend New World screwworm briefing in Texas.

TSCRA

3 of 3:

Leaders of NCBA and TSCRA attend New World screwworm briefing in Texas.

TSCRA

3. Border Defense — Wildlife Migration Prevention
Animals don’t know borders, and that leaves the U.S potentially vulnerable to NWS from wildlife migrating across the border. USDA is working aggressively to ramp up the hiring of USDA-employed mounted patrol officers, known as “Tick Riders,” and other staff who will focus on border surveillance.

The Tick Riders will be complemented by other animal health experts who will patrol the border in vehicles and will provide the first line of defense against an NWS outbreak along the U.S.-Mexico border.

Rollins explains the tick riders, mounted on horseback, will provide the first line of defense against a NWS outbreak along the U.S.-Mexico border.

Next stop: the Texas-Mexico Border, where I rode along the Rio Grande with @USDA Cattle Fever Tick Cowboys!🇺🇸

This dedicated team patrols the border every day to stop the spread of cattle fever ticks and protect our livestock. Their vigilance is essential to also keeping the… pic.twitter.com/2sdryZAYQg
— Secretary Brooke Rollins (@SecRollins) June 18, 2025

USDA will also begin training detector dogs to detect screwworm infestations in livestock and other animals along our border and at various ports of entry. These dogs will be essential to help control the spread of the NWS. USDA is working closely with the U.S. Department of the Interior and the U.S Customs and Border Protection to monitor the border for NWS-infected wildlife that could pose a threat to the U.S.

“We’re also training our beagles on the beagle brigade, to detect screwworm infections, and we will be significantly ramping up our border surveillance program with those and others,” she says.

4. Partner with Mexico – Contain the pest before it reaches our border by enhancing collaboration

Boost surveillance and training
Halt animal movement in affected zones
Improve real-time tracking and response

“We are working directly with Mexico, perhaps in a way never seen before,” Rollins says.

5. Work with our partners in federal, state, and private sector — Educate consumers and protect the U.S. food supply chain

“Once eradicated in the United States decades ago, [NWS] has now reemerged dangerously close to our Southern border — closest to Texas, but also waging a war with our friends in Arizona and New Mexico as well,” Rollins summarizes. “Its peril is not just in the cause, but because it endangers the livelihood of our livestock. It endangers our livestock industry, and it threatens the stability of beef prices for consumers across America. It’s a dinner table issue, as Governor Abbott mentioned, and one that affects every American home and community — directly affecting the cost of groceries and therefore the cost of living. All Americans should be concerned.”

The National Cattlemen’s Beef Association announced continued support for USDA’s aggressive plan.

“American cattle producers commend President Trump and Secretary Rollins for their swift action in combating the spread of New World screwworm. Their leadership and diligence, along with USDA’s collaboration with Texas in building sterile fly production and distribution facilities at Moore Air Base, marks a critical step in stopping the spread of screwworm and protecting the American cattle herd,” says NCBA CEO Colin Woodall. “Today’s announcement of rapid construction of sterile fly facilities, that will boost weekly output of flies to more than 300 million, is vital news for U.S. cattle producers. Producing flies domestically under American oversight will overcome supply challenges in Mexico and Central America — strengthening our fight against New World screwworm and protecting herds on both sides of the border.”

During the question and answer session, Rollins said the ports for Mexican cattle will remain closed until the NWS threat is controlled.

“We’ve been very clear to them over and over again that those ports don’t open until we begin to push the screwworm back,” Rollins says.

Texas Agriculture Commissioner Sid Miller was at the announcement in Austin.

(Texas Department of Agriculture)

“I was pleased to welcome my friend U.S Secretary of Agriculture Brooke Rollins back to Texas and applaud her continued commitment to fight the New World Screwworm threat that puts our state’s $30 billion livestock industry in jeopardy,” he says. “Her announcement about USDA’s plans to construct a new sterile fly production facility in South Texas was welcome news. When completed, it should serve as an important tool in our battle against the screwworm.”

Miller and Rollins have worked together to fight NWS the last six months.

“The Texas Department of Agriculture and I will continue to work side-by-side with Secretary Rollins to develop the tools necessary to combat this insidious threat and protect our agriculture industry and all who depend upon it.”

An Old Parasite Makes a New Comeback Through North America

Thu, 14 Aug 2025 13:22:20 GMT

There are animal diseases for which pig producers have long been on alert and prepared to fight should they come across U.S. borders. One they might not have thought about in decades, or ever — depending on their age — is New World screwworm (NWS), or Cochliomyia hominivorax.

Unfortunately, it’s time to start learning about it again. Last November, Mexico reported NWS had been found inside its southern border, and in May the USDA’s Animal and Plant Health Inspection Service (APHIS) suspended imports of live cattle, horses and bison from Mexico. Recent reports have placed NWS as close as 370 miles to the U.S. border, and at this point it seems less “if” and more “when” NWS is in our country again.

So, what is this screwworm?

Gone for Decades
Native to the Western Hemisphere, the adult NWS is a parasitic fly that lays its eggs in the wounds or orifices of warm-blooded animals — cattle, pigs, pets, even humans (though rarely). It gets its name from the larval maggot, which feeds on the host by screwing itself into flesh. NWS used to be a common worry for livestock producers here, until the USDA and Southern states funded scientific research to mostly drive it outside U.S. borders about 60 years ago.

Between 1962 and 1975 alone, the U.S. and Mexico partnered to release more than 94 billion NWS flies rendered infertile through Sterile Insect Technique lab radiation. The treated males mated with non-treated females in the wild, resulting in population reduction, and by 1986 NWS was effectively driven south of Mexico as well.

In 1994 APHIS and Panama began collaborating to maintain a biological barrier near the Colombian border, which is a narrow land “pinchpoint” relatively easy and affordable to “blanket” with sterile males each year — and the flies have a difficult time crossing that much ocean from elsewhere in South America. During Covid, funding for improving/maintaining the Panama flies factory paused, and fertile NWS flies were back in Central America again by 2023.

In the 1970s, despite a Mexico-U.S. barrier zone, livestock producers in Southwest states still struggled with some infestations and economic losses. In 1976 Texas reported 1.5 million cattle and 333,000 sheep and goats infested with NWS. Adjusted for inflation, APHIS says this infestation now would cost the producers $732 million and result in a loss of $1.8 billion to the state’s economy.

Trade Disruptions
Beyond those APHIS numbers, I don’t have a detailed assessment of the potential market impact of NWS landing in our swine barns. If NWS is identified in the U.S., it’s likely there would be immediate trade restrictions imposed by at least some of our export partners until we demonstrate the country, or at least areas of it, are NWS-free. Although we don’t export many live pigs, and meat and other post-slaughter products are free of NWS, officials in other countries will likely not want to take any chances — particularly Japan, China, and Korea, which don’t have NWS.

How we’ve responded to the NWS in Mexico can tell us a lot about how other countries would likely react to us if and when we find ourselves in Mexico’s position. On top of that, there’s the reality that more than a few countries probably wouldn’t hesitate to take the chance to retaliate against this year’s broad U.S. tariffs.

I can note that southern producers should probably be more immediately worried and on the lookout for NWS because they are closer to Mexico and because the NWS thrives better in their climates than further north. However, this doesn’t mean Minnesota producers, for instance, are immune or shouldn’t also take steps to be certain their biosecurity measures are sound.

Another reason to worry more about possible NWS impact in the South is that the highest concentration of feral swine is in the Southeast (and California), creeping into the lower Midwest. Although most commercial pigs are indoors, in the South there are some raised in a transition barn environment, plus small-scale and show pigs that live outdoors, which could be exposed to nearby wild swine and other potential NWS carriers.

Be Proactive in Programs
I advise any pork producer not already participating in the Swine Health Improvement Plan (SHIP) or Secure Pork Supply Plan (SPSP) to enroll. These are federal-state-industry programs designed to increase confidence among U.S. trading partners in the safety and biosecurity of our swine production.

They provide producers information and assistance with preparing for potential disease, and maintaining business continuity if they do experience an outbreak. As a producer, you can’t personally control how far north the NWS advances, but you can protect your own operations and interests as much as possible.

Other biosecurity measures I recommend at this time are monitoring and education. Know which pigs have open wounds and monitor if they are not healing. Do the same for sows that have recently given birth, young pigs with recently notched ears or docked tails, and vulnerable young piglets generally most susceptible to illness. Also watch for:

● NWS flies are similar in size to house flies, with orange eyes, metallic blue-green body and 3 dark stripes on their back

● Be aware of these in wounds or other orifices: visible egg masses or maggots, bloody or purulent discharge, odor of decay or wounds that enlarge or deepen

● Behavioral signs of possible infection: head shaking, rubbing against surfaces to scratch or signs of pain like depression, irritability, inappetence or isolating

If you do suspect NWS, contact your vet immediately. If they believe it’s NWS, they will notify your state’s top animal health official and the APHIS veterinarian in charge, as well as collect samples for the National Veterinary Services Laboratories. The animal(s) will need to be quarantined until free of NWS and affected premises cleaned with approved larvacidal insecticide, then monitored weekly for a month after quarantine.

USDA Spending to Prepare
CBS News recently reported the USDA expects a new sterile flies factory to be up and running in southern Mexico this time next year. It is also planning to open a distribution center in southern Texas by the end of 2025 to import and distribute flies from Panama if necessary. The USDA wants the Mexican factory in place, according to CBS, because Panama can only breed up to 117 million flies a week and USDA wants capacity for at least 400 million.

Based on various news reports and veterinary warnings, it’s safe to presume NWS will show up either much closer to our border or in the country at some point. Without fearmongering, I do want producers to be as prepared as possible just in case.

Read More on New World Screwworm:
Protect Your Livestock: Signs of New World Screwworm
New World Screwworm: The Billion Dollar Battle at the Southern Border
The Smell You’ll Never Forget: An Animal Infested with New World Screwworm

Tick Riders Join the Fight Against New World Screwworm Threat

Mon, 11 Aug 2025 18:53:22 GMT

With the detection of New World screwworm (NWS) in Mexico, the Tick Riders, a dedicated group of mounted patrol inspectors, will have a new job to tackle.

The Tick Riders have been patrolling the southern U.S. border for more than 100 years. Their mission has been protecting U.S. cattle from the cattle fever tick, a troublesome parasite that causes severe blood loss, weakness and can transmit deadly diseases like babesiosis and anaplasmosis.

The Cattle Fever Tick Eradication Program (CFTEP), established in 1906, uses modern tools like chemical treatments, anti-tick vaccines and injectable medications to manage the threat, USDA Animal and Plant Health Inspection Service (APHIS) explains in a release.

A Line of Defense
Because Mexico continues to report cases of babesiosis, the Permanent Quarantine Zone (PQZ)—stretching from Brownsville to Del Rio, Texas—remains a critical line of defense. Within this zone, Tick Riders monitor for stray livestock crossing the border that may carry these dangerous ticks.

Cattle fever ticks carry bovine babesiosis, which is severe and often fatal.

(USDA)

To help prevent NWS, CFTEP has launched a preventive treatment protocol for all cattle and horses apprehended along the PQZ. Under the new protocol, CFTEP staff will apply NWS-preventative treatments to captured animals.

“These treatments are safe for animals and the environment. They do not replace APHIS’ routine inspections for cattle fever ticks,” APHIS explains.

However, to defend the U.S. from mounting threats of NWS, APHIS is employing these additional measures.

Don’t Accept Unusual
The NWS fly lays eggs and larvae in open wounds of warm-blooded animals,” says Russ Daly, Extension veterinarian for South Dakota State University. “NWS’s function is similar (but different) to a maggot. Domestic blow flies lay their eggs on dead tissue. The resulting maggots feed on the dead tissue. The difference with NWS is it lays its eggs on living tissue and will feed on living tissue.”

(USDA Animal and Plant Health Inspection Service)

NWS is endemic in parts of the Caribbean and South America and has recently spread as far north as southern Mexico.

“As Tick Riders take on this new challenge, they continue to exemplify APHIS’ commitment to protecting U.S. agriculture,” APHIS reports. “Their work helps ensure that farmers, ranchers and producers can keep feeding, fueling and clothing America.”

Daly challenges livestock producers to pay attention to unusual situations. If you have an animal that suddenly has a lot of necrotic tissue that fly larvae (maggots) are trying to clean up, Daly says that’s a sign producers need to take seriously.

“NWS does respond to some insecticides that we would use for show pigs or horses during the summer to keep the flies off,” Daly adds. “But in order to get that animal healed up, the larvae have to be flushed out and removed by a veterinarian. These infestations can lead to secondary infections to worry about. And, if the infestation has gone deep enough, there could be severe muscle damage or damage to other organs that are beyond help.”

Treatment products need to be considered, adds Lisa Becton, assistant director of SHIC. Because of this, wound care is key during NWS infestation.

“If you have animals that have sores, it’s very important to treat that wound,” Becton says. “You may or may not be able to use a sealant, whether that’s iodine or antibacterial. Wound care is very important to help get a wound healing fast, even if you also have to use antimicrobials for an animal to help prevent other infection.”

Learn more:
Protect Your Livestock: Signs of New World Screwworm

New World Screwworm Battle: Texas to Deploy Fly Bait That Mimics Open Wound Scent

Tue, 22 Jul 2025 23:08:43 GMT

Texas Agriculture Commissioner Sid Miller has announced a bold step forward in the battle against New World screwworm (NWS). Working closely with USDA and Secretary of Agriculture Brooke Rollins, the Texas Department of Agriculture (TDA) is spearheading efforts to reintroduce an improved pest control method to NWS — Swormlure Bait .

“The New World screwworm is not just a Texas problem,” Miller says. “This is a nationwide crisis with potential massive implications for American agriculture, which could result in billions of dollars in economic losses and place a heavy burden on our agriculture, wildlife industries and public health systems. We cannot wait for sterile flies alone to turn the tide. That’s why we’re applying a little cowboy logic and bringing back Swormlure, now with an enhanced formula that’s more powerful and effective than ever.”

The NWS issue has shut down cattle imports from Mexico into the U.S.

The NWS was eradicated from the U.S. in the 1960s but experienced an isolated outbreak in the 1970s. It was ultimately eliminated again through a coordinated response that included the release of sterile flies, deployment of the Swormlure-2 attractant, and application of the insecticide Dichlorvos.

What is Swormlure?

A synthetic bait designed to attract adult screwworm flies, Swormlure may be highly effective when combined with insecticides, such as Dichlorvos, in eradicating NWS. Miller has directed TDA to lead development and deployment of this bait to enhance eradication efforts.

“Swormlure-5, created using modern science and built upon previous versions — Swormlure-2 and Swormlure-4 — is a potent synthetic attractant that mimics the scent of open wounds, drawing adult screwworm flies to the bait, where they die,” Miller explains.

Swormlure-5 bait, when used as an attractant and capture tool, is highly targeted. The attractant only impacts screwworm and blow flies and should pose no threat to beneficial insects such as honeybees, monarch butterflies or other pollinators.

“Today, we’re doing it smarter, faster and stronger. Swarmlure-5 bait will attract and trap flies, specifically screwworm and blow flies, which are both better off dead,” Miller adds. “In prior research and deployment, this method eliminated approximately 90% of the flies within a two-to-four-week period. The remaining 10% were eliminated with the release of sterile male flies in the areas where traps were deployed.”

This effort should reinforce existing sterile fly operations and supercharge early detection and suppression of screwworm fly populations.

This collaboration with USDA and Rollins emphasizes Texas’ leadership in agricultural biosecurity. TDA will coordinate the deployment of specialized Swormlure-5 traps to monitor and control potential hotspots in collaboration with USDA, the Government of Mexico and other state and federal partners.

“We’ve beaten the NWS before, and we’ll do it again. But it will take all hands on deck,” Miller adds. “We need another success story like we had in the ’70s, and I believe Swormlure-5 bait is the game-changer that will get us there.”

Your Next Read: The Smell You’ll Never Forget: A Calf Infested with New World Screwworm

The Smell You'll Never Forget: An Animal Infested with New World Screwworm

Thu, 10 Jul 2025 16:41:23 GMT

“The stench…it’s like roadkill stewed in infection,” explains Jose Santiago Gallardo Espinosa, a cattle producer from Chiriqui, Panama, describing an animal that has been infected with New World screwworm (NWS). “You’ll smell it before you see it.”

He goes on to describe the appearance. “That little dehorning scrape you didn’t worry about? Now, it’s a fist-sized hole pulsating with maggots. Not on top, under the skin. Hundreds of cream-colored worms with screw-like spines, eating your cow alive.”

It’s a Plague in Panama

Gallardo is a Panamanian livestock production specialist and animal science professional with a diverse and practical background in cattle production, agricultural policy and international ranch management. He currently serves as the technical assistance team manager at Cooleche, R.L., where he leads strategic initiatives in cattle production and technical outreach.

“⁠This ain’t ‘just flies.’ We’ve buried calves eaten alive in 48 hours,” Gallardo stresses. “Post-calving cows are sitting ducks, I found one last week with maggots deep in her vulva, she was trembling as she tried to nurse her calf.”

An animal health professional treating an animal in Panama that has been infected by New World Screwworm.

(Jose Santiago Gallardo Espinosa)

To catch NWS and stop the spread, Espinosa encourages daily wound checks including navels on newborns, vulvas on fresh cows, sheaths on bulls, branding cuts and tagging nicks. Some red flags include a wound that swells overnight or oozes cloudy fluid and a milk tank mysteriously dropping.

“Treat every scratch like a ticking bomb,” he says adding if you find one with a wound acting a little strange, you should “peel back skin edges, and if you see rice-grain maggots with dark spines — sound the alarm.”

He says more than 6,500 cases have erupted across Panama, marching north through Central America like a plague.

“For years, our U.S.-Panama barrier kept NWS at bay,” Gallardo says. “We’d see maybe 25 cases a year — it was a nuisance, not a crisis. Then 2023 hit, and overnight our pastures became war zones.”

He says the reality in Panama is rainy season is maggot season.

“Here, in Chiriquí’s dairy country, it is the perfect storm,” he says. “Rainy season humidity of 90%, 85°F heat and flies everywhere. A single-infected cow bleeds $10/day in lost milk — its life or death for small dairies.”

NWS in Nicaragua

Ernesto José Sequeira Enríquez, an agronomist from Camoapa, Nicaragua, says NWS was eradicated from Nicaragua in the 1990s. He says he first encountered it during an internship in Brazil where he experienced the serious challenge the fly causes.

“When cases began appearing here again last year, I was able to use what I learned in Brazil to prepare veterinary supplies and train people on prevention and treatment,” he explains.

(Ernesto José Sequeira Enríquez)

He says it’s essential to enforce a daily inspection routine, checking every animal carefully for open wounds.

“When you find an infected animal, you’ll typically see a bleeding wound,” Sequeira says. “If the infestation has progressed, there will be a strong, foul smell due to tissue damage and the presence of larvae.”

He encourages U.S. producers to be prepared with sufficient supplies of veterinary medicines and insecticides for both treatment and prevention and to adjust management practices to reduce risk. For example:

When dehorning, branding or ear tagging, apply insecticide spray to the wound immediately.
Ensure proper care of newborn calves by disinfecting the navel with iodine solution as soon as possible, since that is the most common entry point for infestation.

“Although complete control of screwworm is not possible, taking preventive measures significantly reduces the economic and productivity impact of it,” he says. “Early detection and consistent preventive practices are critical to minimizing losses.”
Sequeira stresses a producer’s eyes and hands are their best tools to fight NSW.

“My warning to U.S. ranchers is this isn’t just a Panama problem,” he summarizes. “Newborn calves are maggot magnets. If you lose one calf to a navel infestation, you’ll never sleep again. Make inspections sacred — no excuses. Report fast and hide nothing.”

It’s Endemic in Brazil

Marcelo Costa is a veterinarian, professor and cattle business consultant in Brazil and Paraguay. In 1999, Costa was taught embryo transfer at Camp Cooley in Franklin, Texas. He then returned to his family’s third generation ranching operation where they started Camp Cooley Brazil.

“I have been dealing with screwworm all my life since it is endemic in Brazil,” Costa says. “Screwworm-infected animals happen all months of the year.”

A wound in the animal skin full of screwworm and new fly eggs in the skin borderline

(Marcelo Costa)

Like others, he has experienced finding infected animals with bleeding, foul-smelling wounds. He says animals show discomfort and may not follow the herd as normal.

“Newborn calves are usually the more attacked category because of the navel’s wet and bloody tissue,” he says. “If a screwworm infects the navel, it may open a door at the site for more severe infections that may cause diarrhea, pneumonia and other diseases.”

Costa stresses how much NWS costs producers beyond animal loss and decreased productivity.

“One of the biggest problems with NWS is the increased labor with vigilance and animal treatment,” he summarizes.

Guatemala Producers Are Learning to Cope with NWS

“Screwworm came to teach us the times are changing, and that any type of production is possible and open to any complication,” says Oscar León, a livestock production specialist and agricultural business administrator from Guatemala City, Guatemala. “Brazil learned how to cope with it, and Guatemala is in the process of it. The U.S. is not exempt from it, unfortunately. But with the adequate measures and prevention techniques, one can learn and teach others. We can make the impact less harmful on our production and wallets.”

(Oscar León)

León currently manages his family’s cattle operations and leads LAVAT S.A., a company that imports and distributes innovative animal health and nutrition products tailored to the needs of the Guatemalan livestock sector.

He explains it is important for producers to look for and treat any open wound or bruise as they are the first indicators.

“If an open wound smells like the scent of rotten meat, you will find the presence of screwworms feeding off live tissue,” he says. “Prevention and early timing are the best ways to treat screwworm. Make sure to take your time, observe your cattle, search for a bruise or wounds and treat them properly.”

He also stresses the importance of making sure everyone who works in the farm or ranch is aware of NWS and knows how to react if an infection is found.

Educating U.S. Producers

Chris Womack, a veterinarian and rancher from San Angelo, Texas, says he remembers helping his dad treat calves with NWS infestations.

“I can still remember the smell,” Womack says. “I thought it was cool because I was a little kid, and we dug maggots out of the calves. I can still smell it like it was yesterday, and it was horrible to look at them.”

Womack shares a historic context of NWS, which he says means “man-eater,” on the “Registered Ranching” podcast with Tucker Brown.

Womack also describes the emotional toll on the producer when faced with NWS.

“If you’re a steward of an animal and it has half of its head rotting off, or its abdomen is a gaping wound because the maggots are eating it up, or it gets in their ear and they’re walking around in circles with brain damage because they got meningitis, well, it’s devastating.”

Womack summarizes NWS isn’t just an agricultural issue, it’s a human health concern. Historical accounts and recent data from Panama show NWS can affect humans, particularly vulnerable populations like homeless individuals or those in areas with limited medical access.

Womack says the experiences with NWS during his childhood is the reason he is a veterinarian today. He says there is a generational ignorance in the U.S. regarding NWS, and that is something he is committed to fixing.

“The only way we can overcome ignorance is education,” he stresses.

Your Next Read: Breaking: Mexican Border Closed Again as New World Screwworm Comes Within 370 Miles of the U.S.

New World Screwworm

“Report, Don’t Hide It”: Experts Urge Rapid Action When Suspecting New World Screwworm

1. Prepare, Don’t Panic

2. Eyes on Animals, Surveillance is Central.

3. Report First, Don’t Hide It.

4. Vet Relationships Are Essential.

5. Wildlife Matters in This Fight.

6. Quarantines Are Tools, Not Punishments.

7. More Tools in the Toolbox.

Screwworm Fight: $750M Sterile Fly Facility Groundbreaking in Texas

How Close Is NWS to the U.S.?

How Does Sterile Fly Production Stop Screwworm?

What is the Timeline for the Edinburg Facility?

Why is Domestic Fly Production Important for U.S. Agriculture?

USDA’s "Male-Only" Fly Breakthrough to Transform Screwworm Eradication

Moore Air Base: On Time and On Budget for 2026 Production

The Science of Stopping the Spread: Why Male-Only Matters

Regulatory Road Map: The EPA Public Comment Period

USDA Updates New World Screwworm Response Playbook for Ranchers and Vets

Refining the Rules: Key Updates to the 2026 Playbook

Collaborative Design: Incorporating Tribal and Industry Expertise

Accessing the Playbook: Resources for Producers and Responders

How Will U.S. Producers Maintain Business when New World Screwworm Invades?

Surveillance: Eyes on Animals

Treatment: Limited Tools, Use Strategically

Movement Controls: Targeted, Not Statewide Shutdowns

NWS is Not a Food Safety Issue

USDA Announces Sterile Fly Production Facility Construction Contract

U.S. Begins Dropping Sterile Flies in Texas to Stop Screwworm

New Action To Prevent Northward Spread

Sterile Flies are Key to Stopping NWS

Surveillance, Monitoring and Reporting Continues

Texas Takes Preemptive Action

USDA Announces New World Screwworm Grand Challenge

Priority Areas for Funding

New World Screwworm Confirmed in Pig in Mexico

A Threat to the U.S. Swine Industry, Too

Read More:

New World Screwworm Found in Newborn Calf 197 Miles from U.S.-Mexico Border

What Are Some Key Concerns if NWS Crosses the Border?

Sterile Flies Remain Key to Eradicating New World Screwworm

FDA Approves Exzolt Cattle-CA1 for Prevention and Treatment of New World Screwworm

Administration and Use Considerations

Second Screwworm Detection 120 Miles from U.S. Border

USDA Launches Screwworm.gov

NWS Update

Cross-Border Response and Collaboration

Protecting the Border and Maximizing Our Readiness

Taking the Fight to NWS

Next Step in the Screwworm Fight: USDA Announces Opening of Sterile Fly Dispersal Facility in Tampico, Mexico

Trade Mission While In Mexico

Preparing for the Battle Continues: USDA Shares Screwworm Update and Releases NWS Playbook

NWS Playbook Released

Playbook Highlights

The Importance of Wildlife Monitoring for New World Screwworm

Screwworm Fly Migration

Wildlife Affected by New World Screwworm

How can you help monitor wildlfe?

Winter: The Secret to Slowing the Spread of Screwworm

The Winter Win

Fly Season

Rainfall and Monsoon Factors

New Technology to Combat New World Screwworm

U.S.-Mexico Border Battle Continues As the Threat of New World Screwworm Intensifies

Mexico’s Response To New World Screwworm

U.S.-Mexico Border Remains Closed to Cattle Trade

Texas Rancher Weighs In On Impact of New World Screwworm

Mexico Confirms Case of New World Screwworm 70 Miles from U.S. Border

New World Screwworm Numbers Increasing in Mexico

Human Case of New World Screwworm Confirmed in Maryland

Emergency Use of Animal Drugs Approved to Combat New World Screwworm

Breaking News: USDA to Invest $750 Million to Build a Domestic Sterile Fly Production Facility

An Old Parasite Makes a New Comeback Through North America

Tick Riders Join the Fight Against New World Screwworm Threat

New World Screwworm Battle: Texas to Deploy Fly Bait That Mimics Open Wound Scent

What is Swormlure?

The Smell You'll Never Forget: An Animal Infested with New World Screwworm

It’s a Plague in Panama

NWS in Nicaragua

It’s Endemic in Brazil