SVA Talk Goes Viral

Friday, May 22, 2026

By Geoff Geddes

Online, “going viral” is the goal, but on farm, it’s as welcome as the flu. Intruders like Senecavirus A (SVA) harm production, profits and sustainability. In battling these threats, it helps to know your enemy, so that was the goal of the talk on Seneca Virus A at this year’s Manitoba Swine Seminar.

“Since 2015, SVA cases have increased in Canada, the U.S., Brazil and China,” says Dr. Jette Christensen, manager of the Canada West Swine Health Intelligence Network (CWSHIN).

The first case in a swine herd in Canada was detected in 2019. While SVA is not a reportable disease, the clinical signs make it indistinguishable from Foot and Mouth Disease (FMD). As a result, the guidance for suspect cases in countries free of FMD like Canada are extensive. Following investigation by the Canadian Food Inspection Agency (CFIA), samples are sent to an approved lab and temporary movement restrictions are imposed pending the lab results.

SVA has also contaminated assembly yards in Ontario and Manitoba, causing some issues for the export of culled sows to the U.S. This prompted scrutiny from the United States Department of Agriculture (USDA) or CFIA, including 19 vesicular disease investigations by the CFIA in 2024.

“A major issue with SVA is that it causes skin lesions, a symptom that must be reported to CFIA because it is often triggered by a foreign animal disease (FAD),” says Dr. Christensen. “Freedom from FADs is critical for Canada’s export of pigs and pork.”

The ins & outs of Foot & Mouth

One of the most severe FADs is Foot and Mouth disease (FMD), a highly contagious virus affecting pigs and cattle, as well as sheep, goats, deer and other cloven-hoofed ruminants. Its symptoms include fever and blister-like sores on the tongue and lips, in the mouth, on the teats and between the hooves. Though FMD does not lead to widespread fatalities, it can greatly impair production through weakened and debilitated animals.

Lesions could also be a sign of Swine Vesicular Disease (SVD), another contagious, fever-inducing disease marked by vesicles (fluid-filled blisters) in the mouth, snout, feet and teats. This virus can be easily confused with FMD, as the lesions with each one are virtually identical.

Vesicular Stomatitis (VS) also mirrors FMD in the form of vesicular lesions.

“VS is spread by midges and attacks all cloven-hoofed animals, causing fever and lesions,” says Dr. Christensen. “It rarely leads to death, but since VS lesions are also indistinguishable from FMD, it is a real cause of concern for industry.”

A legion of lesions

In the course of production and shipping, lesions may appear at a variety of points. A producer or barn worker could spot them in the course of their daily routine, or a herd veterinarian might pick them out during a barn visit. As well, lesions might be seen at an assembly yard or by the USDA at the border and be traced back to a certain herd.

Wherever it occurs, the detection of lesions is a red flag that calls for immediate action. By posting a barn checklist, producers and their staff can ensure a consistent response and effective action in the heat of the moment.

“Topping that list should be notifying your private vet as soon as possible and ceasing all pig movements until an investigation is conducted,” says Dr. Christensen. “The vet will decide if the suspicion of FAD warrants notifying the CFIA.”

If CFIA is looped in, they will provide direction on next steps. In case that guidance is delayed, workers should be advised of the proper response. Everyone must shower out of the barn or, if that is not an option, at least change into clean clothes. Staff should shower again at home and place farm clothing in the washing machine or a sealed plastic bag.

Vehicles are another key focal point in this situation. Any vehicles that are parked outside the controlled access zone (CAZ) and away from the barn should be clean. Where there is a strong suspicion of FAD, cars and trucks that exit the premises should go immediately to the nearest car wash.

“Though these comprise the most obvious steps, there are other things to consider,” says Dr. Christensen. “Do any of your employees carpool? If so, get the names and, if any are barn workers suspected of disease, make alternate arrangements while the threat of disease persists.”

What about staff living with a pig worker from another farm? Where the probability of disease at the first worker’s farm is high, a roommate or partner should refrain from attending their farm the next day. By taking this safeguard until the suspected farm is thoroughly examined, employees can help contain the risk of disease spread.

“One challenge in all of this is that in addition to FADs, vesicles could also be caused by something else entirely, such as mechanical wounds, chemicals, sun burn or frostbite,” says Dr. Christensen. “Until you know for sure, you should always advise your herd vet when lesions appear; however, you still need tools to navigate the complex investigations that will follow.”

Ruling out & plugging in

If CFIA concludes “what it isn’t” and rules out FAD, that’s a good start, but your vet must then determine what it is. In a joint effort involving CWHSIN and the Western Canadian Animal Health Network (WeCAHN), phase 1 of the Outbreak Support Network (OSN) was completed in December, 2025.

The OSN aids producers and vets, especially in the pork sector, in knowing what to look for, what happens next, and how best to protect Canada’s pork industry from disease-related trade disruptions (cwshin.ca/outbreak-support-network).

Though a world devoid of illness is a worthy goal, it’s not one to pin your hopes on. As Dr. Christensen explains, vesicles will always be an unsettling sight in a pig barn. Like any unwelcome presence on farm, the key is knowing what to do before you need to do it.

“There is always something to deal with in this business. When it comes to SVA and FADs, access to the proper tools and guidance will leave you better prepared for a worst-case scenario.” BP