Ontario Animal Health Network (OAHN) Swine Network Quarterly Veterinary Report

Senecavirus A (SVA) Ontario Update

Starting in 2015, Senecavirus A (SVA) has caused intermittent complications with respect to the export of Canadian cull animals to the United States. This disease resembles reportable swine vesicular diseases. This is a national issue and since June 2025 has impacted Ontario cull sow movements.

In July 2025, the APHIS and the USDA removed the export eligibility status for a cull sow assembly in Ontario due to SVA lesions being seen in cull sows sent to a USDA processing facility. These lesions initiated foreign animal disease investigations at this US processing plant. The suspect animal(s) were initially quarantined for individual inspection and further testing. Since the initial site, more Ontario cull sow assembly sites have also had their export eligibility status revoked by APHIS and the USDA for similar reasons. The affected assembly sites accept cull sows from Quebec, the Maritimes and Ontario. Each affected assembly site has now actioned the USDA requirements including removing all animals from each site to thoroughly clean and disinfected before they were able to regain their export status. The assembly site operators worked closely with veterinarians to develop the required SOP’s and have now completed actioning the USDA listed requirements. All Ontario cull sow assembly sites have re-gained their export status to the U.S.A, but some are still under a 60-day requirement for vet inspection on each load going to the U.S.A.  After this 60-day period expires these sites will be able to export normally as long as no further SVA typical lesions are detected at U.S. processing plants. Export restrictions on these assembly sites caused disruption and had significant effects on the eastern Canadian cull sow system. Similar export issues related to SVA, have arisen previously in western Canada. It is important to continue inter-provincial industry collaboration on this issue.

Producers and veterinarians in all provinces need to understand that lesions can be mild and hard to notice in some animals. Diligence is required to check all animals for SVA type lesions including blisters, ulcers on the snout, ears, face, on the coronary band or between the claws on the feet before shipping them for slaughter, cull markets and or directly for export to the USA.  (Source Poster below: Swine Health Ontario)

SVA On-Farm Case Detection in Ontario

Dr. Christa Arsenault provided an update that there is currently one on-farm case of SVA in Ontario. This farm sent cull sows to a cull sow assembly site in Ontario and lesions were noted at the cull sow assembly site on one animal. This prompted notification to the Canadian Food Inspection Agency (CFIA) who then conducted an on-farm investigation with the herd veterinarian present. There were no pigs with snout lesions seen at the time of this investigation and only potentially two animals that were seen with blisters near the bulbs of the heel. Diagnostic samples taken by the CFIA from this farm were positive for SVA.  The veterinarian involved reported that clinical signs of SVA were extremely mild on this farm and could easily be missed by veterinarians and producers.  Loose sow housing also complicated being able to find only a few animals with clinical lesions.  The initial clinical sign that presented in this herd was a scour in only a few pens of nursery pigs for 1 week in duration. All affected pigs were normal within 3-5 weeks. Nursery pigs from the oldest group that scoured were sent to the AHL for testing and tested SVA negative on PCR test. There was no scour in nursing piglets and no increased mortality. Some sows did go off feed for 3-4 days. The source of infection is unknown. This herd is currently working with their veterinarian on eliminating the virus.

Swine Health Ontario (SHO) has taken the lead providing SVA updates and critical messaging to Ontario swine producers and industry members. Several updates have been sent out by SHO to date and additional resources can be found on their webpage here. SVA is an immediately notifiable disease to the Ontario Ministry of Agriculture, Food and Agribusiness.

Porcine Epidemic Diarrhea (PEDV)/ Porcine Deltacoronavirus (PDCoV)

Jessica Fox the manager of Swine Health Ontario (SHO) provided an update on PED and PDCoV cases seen in Q3 of 2025. This quarter has seen a significant decrease in cases, with a total of two cases, one PED case in a finishing barn and 1 PDCoV case in a nursery-finishing barn).  Both cases tested positive in early July.  However, as the winter and cold weather are now here, SHO urges producers and those in the swine industry to stay vigilant with biosecurity to try to reduce the amount of PED and PDCoV cases that we see this season.  During the last week of November, SHO ran a PED and PDCoV Awareness Week, where they provided important resources and reminders to the members of the swine industry as we move into winter.

SHO continues to support elimination as the best strategy for disease control. Producers are encouraged to continue to be diligent in testing for coronaviruses in all gastrointestinal cases, as PDCoV can present with minimal clinical signs. Timely diagnosis of these cases can help limit widespread contamination and potential spread to other sites.

Enhanced biosecurity measures need to be taken by all swine producers, veterinarians and swine industry members during these high-risk periods. All assembly yards, animal resting locations and processing docks should be assumed to be positive for various infectious agents such as PED/PDCoV, PRRS, Influenza etc.  Care must be taken to avoid contamination of trailers, footwear and clothing when visiting these high-risk sites.  

Producers are also encouraged to promote the use of SHARC by producers to stay aware of current positive sites in their proximity. If you are interested in enrollment please contact Jessica Fox Jessica.fox@swinehealthontario.ca. The PED and PDCoV Tracking map is available on the Swine Health Ontario website and shows current and annual cases by county. http://www.swinehealthontario.ca/Disease-Information/PED-PDCoV-Tracking-Map

Influenza A (IAV) in Ontario swine

There were 22 positive case submissions for Influenza A in Q3 of 2025. This is lower compared to Q3 of 2024  and Q3 in 2023. For this quarter, partial (29%) and H1N1 (29%) subtypes were the most dominant, followed by H3N2 (24%). This differs from Q3 of 2024 and 2023, where H3N2 was the most dominant subtype (68% and 70%, respectively). Most of the IAV detections this quarter were from “non-specified” age, followed by grow-finish pigs. All H1N1 isolations were of the pandemic clade, and most of the H3N2 isolations were of the 2010.1 clade. (See graphs below that demonstrate Influenza subtypes detected in Ontario swine. Legend: Red boxes indicate similar quarters (July-Sept) and the red arrow indicates the current quarter 3 pie graph).

OAHN Projects- Now Accepting Samples!

Dr. Josepha DeLay and Dr. Christa Arsenault provided an overall OAHN swine projects update. Reminder project #1 on PCV-2 and project #2 on Sapovirus are both now open and accepting samples!

Project #1- The first project aims to assess Porcine Circovirus type 2 (PCV2) prevalence in the Ontario herd, specifically the different PCV2 subtypes. PCV2 PCR-positive samples submitted to AHL are eligible, and this project will sequence these samples to determine subtype. These results will allow for better understanding of the distribution of different PCV2 subtypes within the province. A short survey will accompany these submissions to better understand clinical picture of each case.  There have currently been 19 cases tested thus far, with the following results: 16% PCV2a, 63% PCV2d and 21% untypable.

Project #2- The second project will focus on the neonatal diarrhea complex and the role of Sapovirus in these cases. Eligible cases will be those with piglets less than 20d of age presenting with a clinical scour and an accompanying Sapovirus PCR-positive result. This project will evaluate these cases by testing for a wide range of pathogens, including porcine bacteriology enteric panel, Rotavirus PCR, Sapovirus PCR, Coronavirus triplex PCR, fecal flotation, and histopathology. This project aims to allow for better understanding of how Sapovirus contributes to neonatal diarrhea cases, especially amongst other common pathogens.

Any questions can be directed to Dr. Christa Arsenault christa.Arsenault@ontario.ca. Ask your veterinarian to participate if interested!

International Disease Topics Of Interest Summary

Swine Brucellosis in Denmark

Dr. Conor Voth provided and update on a new outbreak of Swine Brucellosis in Denmark to the OAHN Swine Network.

Brucella suis is a bacterium that causes swine brucellosis, a zoonotic disease (can affect both people and pigs). It leads to chronic inflammation in the reproductive organs, often resulting in abortion in pregnant sows, as well as orchitis, infertility, lameness, paralysis, and abscesses. Transmission occurs mainly through ingestion of infected tissues or fluids, contaminated semen during breeding, and nursing from infected animals. In the United States, B. suis was the first biological agent weaponized in 1952 and was field-tested with B. suis-filled bombs.

After 25 years without cases, Denmark confirmed an outbreak of Brucella suis biovar 2 in a free-range pig herd in Herning on August 22, 2025, verified by France’s ANSES reference laboratory. The herd of 3,850 pigs showed reproductive losses but no deaths, prompting testing earlier in August. The outbreak raises economic and zoonotic concerns, though no human infections have been reported. The source remains unknown, but B. suis biovar 2 is endemic in wild boar and European hares, common infection sources for domestic pigs. Denmark’s outdoor pig farms use double fencing, and while wild boar are absent, stray animals from neighboring countries are occasionally culled. The incident has disrupted trade, invalidating Denmark’s five-year brucellosis-free export exemption and suspending pig movements within the EU, except from farms with strict indoor housing and biosecurity. The Danish Veterinary and Food Administration is now developing a pre-movement monitoring program to restore certification and export capacity. Source: (SHIC, Swine Disease Global Surveillance Report, September 2025)

How can you Participate in OAHN?

Look for the 2025 Q4 veterinary clinical impression survey that will come out the first week of January 2026 via an email through the OASV listserv.

If you are a practicing vet that sees swine in Ontario, please complete this survey when the email reminders are sent out through the OASV listserv.