Ontario Animal Health Network (OAHN) Swine Network Quarterly Industry 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, another 2 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 must action the USDA requirements including emptying each assembly site so that it can be thoroughly cleaned and disinfected before each affected site could regain their export status. The assembly site operators are working closely with veterinarians to develop the required SOP’s, and to begin actioning the USDA listed requirements. This export disruption will have the potential to create significant effects on the eastern Canadian cull sow system.  While the process is started, it is expected to take an undetermined amount of time to action all of the USDA requirements. 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 involved in export inspections, need to be diligent in checking 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.

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 Q2 of 2025. Jessica reported that for this quarter, there were 9 PDCoV cases and 12 PED cases. For the PDCoV cases, 3 were sow units and the 6 were nursery-finish, all of which were movement-related (not independent outbreaks). For the PED cases, there were 5 sow barn cases and 7 nursery-finish cases, 6 of which were movement-related. Overall, the case load was decreased compared to Q1 2025 and Q4 2024, which is likely a result of the warmer weather combined with increased industry vigilance. Jessica reminds those in the industry to continue to stay mindful about biosecurity to help reduce PED and PDCoV cases.

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)

There were 31 positive case submissions for Influenza A in Q2 of 2025. This is higher compared to Q2 of 2024 but reduced from Q2 in 2023 where there were 48 positive submissions. Over half of the positive detections in Q2 2025 were typed to be H3N2, and there was one mixed isolation (H3N2 and H1N1 detected in the same sample). Most cases this quarter were from the grow-finish stage. The majority of sequenced submissions in Q2 2025 were of the H3N2 2010.1 clade, which is consistent with the previous quarter.

OAHN Swine Projects- Now Accepting Samples! Ask your veterinarian to participate for free testing

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 Animal Health Lab (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.

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 20 days 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.

Ask your veterinarian to participate if interested!

International Disease Topics Of Interest Summary

New World Screwworm

Dr. Conor Voth provided an update on New World Screwworm (NWS) to the OAHN Swine Network.

The New World Screwworm (NWS), a parasitic fly that infests livestock wounds, was largely eradicated from the U.S. and Mexico by the 1980s through a massive sterile insect release program. However, NWS was recently detected again in southern Mexico in late 2024, threatening to re-enter the U.S. This parasite causes severe economic losses, with historical infestations in Texas alone estimated to cost the equivalent of $732 million today.

NWS larvae feed on warm-blooded animals’ flesh, damaging cattle, pigs, and even humans. The parasite thrives in southern climates and poses a particular risk to southern U.S. producers, especially with high feral swine populations acting as potential carriers. Although commercial pigs are mostly indoors, outdoor small-scale operations and show pigs remain vulnerable.

The USDA has responded by suspending imports of live cattle and other livestock from Mexico and plans to enhance sterile fly production capacity. A new sterile fly factory is expected in southern Mexico by 2026, alongside a Texas distribution center to support rapid response.

Producers should monitor animals closely for wounds that fail to heal, visible larvae, foul odors, or behavioral signs like irritability or inappetence. Suspected cases require immediate veterinary attention, quarantine, and larvicide treatment.

The reappearance of NWS may lead to trade restrictions on U.S. pork exports from countries free of the parasite, including major markets like Japan, China, and South Korea. Producers are encouraged to join programs like the Swine Health Improvement Plan or Secure Pork Supply Plan, which provide guidance on biosecurity and outbreak preparedness to help safeguard operations and maintain market access. Source: (Preparing to deal with New World screwworm: The next generation – Clayton Johnson, National Hog Farmer)

Mexico has recently reported 35 human infections, while Costa Rica has seen 56. An 86-year-old woman in Mexico is the first confirmed death associated new world screwworm, as a result of the infection compounding with skin cancer. In Mexico illegal cattle smuggling has been linked to the spread. Source: (2025-08-03 – CEZD Weekly Intelligence Report)

Topics of Interest- Can American Veterinarians and Labs Keep Up with an ASF Outbreak?

This study developed a model simulating ASFV spread over 150 days in a densely populated U.S. swine-producing state to estimate the sampling resources needed for outbreak management. The model predicted a median of 27 outbreaks, requiring over 3,000 barns sampled and up to 84,830 blood samples or 14,195 oral fluid samples collected, depending on the sample type. To prevent sampling delays, between 136 and 367 sample collectors would be needed under median epidemic conditions, but this could rise to over 3,000 in worst-case scenarios.

The study highlighted that sample collector availability is affected by downtime—periods when collectors cannot visit farms due to biosecurity restrictions—which increased the number needed by 28% to 75%. Switching from blood samples to oral fluids reduced collector requirements by up to 75%. Laboratory capacity also emerged as a bottleneck; with a daily processing limit of 1,000 samples, backlog could delay results for months or even years. Redistribution of samples to other labs would be necessary to avoid such delays.

The study emphasizes that current U.S. ASFV response plans, which rely heavily on swine veterinarians for sampling, may be insufficient in a large outbreak. To address this, a certified training program for on-farm personnel aims to increase the pool of qualified sample collectors. These findings inform strategic planning by identifying the scale of manpower and lab resources needed for effective ASFV surveillance and control. The model underscores the importance of flexible, scalable response systems to manage potential ASFV incursions, helping safeguard the U.S. swine industry’s health and economic stability. Source: (Galvis, AJ. A., Estimating sampling and laboratory capacity for a simulated African swine fever outbreak in the United States, Preventive Veterinary Medicine, 239)

In Ontario, it is expected that in the case of an ASF outbreak, we could potentially experience similar issues with not having enough swine veterinarians to aid with sampling requirements, however the Animal Health Lab at the University of Guelph does not estimate any issues regarding surge capacity for testing from a laboratory perspective as is stated would be an issue in U.S. labs.

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