Recent outbreaks of Senecavirus A (also known as Seneca Valley virus) in show pigs prompt the importance of biosecurity, good stockmanship and communication with your veterinarian, says Patrick Webb, assistant chief veterinarian at the National Pork Board.
Senecavirus A, a small, non-enveloped picornavirus, has been circulating in U.S. pigs since at least 1988.
“The challenge with the virus is that it’s indistinguishable from foot-and-mouth disease (FMD) as far as how it looks in a pig,” Webb says. “They get vesicular lesions (blisters) on their snout and around the top of their hooves, around the coronary band. They can get blisters in between the hooves.”
What is Senecavirus A?
This FMD look-alike is interesting, he says. When a pig gets infected with it, clinical signs typically show up three to five days later.
“That’s when you’re going to see a bit of lethargy and fever, but more importantly, you will see vesicular lesions,” Webb says.
Don’t expect to see the actual blister, he points out. Because the snout and feet are high-motion areas, blisters don’t last very long. You may see areas that look like a scab because the blister has popped.
“Think about a blister popping on your hand and what it looks like,” Webb says. “Seeing blisters is pretty rare. Seeing popped blisters that are crusty and gross and may have a secondary bacterial infection starting up is more common.”
The virus can shed in nasal secretions, oral secretions and in manure for almost 30 days. It also seems to “set up shop” or “hide out” in the tonsils. When a pig is stressed, some reports say pigs can start shedding the virus again.
Webb says it seems to be a hardy virus, but many common disinfectants work well against it.
The Swine Health Information Center fact sheet on Senecavirus A says the efficacy of many disinfectants against SVA remains unclear. Because vesicular diseases are clinically indistinguishable, disinfection protocols for FMD should be followed even if SVA is suspected. This includes use of sodium hydroxide, sodium carbonate, 0.2% citric acid, aldehydes, and oxidizing disinfectants including sodium hypochlorite. Learn more here.
Report Immediately
Since Senecavirus A looks like FMD, a foreign animal disease, it needs to be reported to your local veterinarian or state veterinarian immediately, Webb says. As Senecavirus A has become more common, it has resulted in some desensitization to these vesicular lesions.
“It used to be ‘Oh blisters, that’s a big deal.’ Now it’s ‘Oh blisters. It’s Seneca, and that’s the wrong mindset,’” Webb says. “We need to have vesicular lesions looked at by a veterinarian, and potentially have a foreign animal disease investigation done, because it’s clinically indistinguishable from FMD. We must make sure FMD doesn’t sneak in undercover.”
If you don’t work with a veterinarian, he urges show pig exhibitors to connect with their state veterinarian. This has become more common in areas with less access to veterinary care. Building that relationship is very important for the good of the entire swine industry, he adds.
Prevention of Senecavirus A
Both direct and indirect transmission are likely to play a role in the spread of Senecavirus A. This virus has been identified in mice and houseflies. Webb points out that transportation and commingling of pigs is a common way for the disease to spread. Reports have shown in some cases that no lesions existed on pigs loaded onto trucks bound for long-distance harvest facilities. However, by the time they arrived at the plant, lesions were present.
“There seems to be, at least anecdotally, the ability for this virus to maybe reoccur and result in lesions in a short period of time,” Webb explains.
Senecavirus A has been a challenge at packing plants during upticks of the virus that seems to ebb and flow based on the season.
“When vesicular lesions show up in pigs at the packing plant, it starts a foreign animal disease investigation that disrupts the plant schedule,” Webb says. “Although it seems like it’s not as hot and heavy as it was when we first really saw Seneca floating through the industry, it’s here to stay.”
For show pig producers and families, Webb wants people to be aware that Senecavirus A is out there. This virus does not present a risk to human health or food safety, but it does require veterinary consult.
“Everything we do to prevent influenza, porcine reproductive and respiratory syndrome, porcine epidemic diarrhea and more, all apply the same as Senecavirus A,” he says. “Good biosecurity and good traceability through Ag View are important. If your pigs are sick at home, have your herd veterinarian come and take a look at them. If you do see vesicles, call your veterinarian or the state veterinarian’s office and report it. Don’t take sick pigs to exhibitions. If they’re clinically ill, separate them out and contact your herd vet. If you start to see clinical signs at shows in your pigs, report it to the veterinarian at the fair.”
Senecavirus A Resources:
Senecavirus A Fact Sheet by Swine Health Information Center
