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.
Read more about USDA’s NWS Playbook:
Preparing for the Battle Continues: USDA Shares Screwworm Update and Releases NWS Playbook
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:
- F10 Antiseptic Wound Spray with Insecticide Approved to Prevent and Treat New World Screwworm
- FDA Approves IVOMEC to Help Protect Cattle Against New World Screwworm
- 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
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.
