Ontario Animal Health Network (OAHN)
Companion Animal Network Team
Veterinary Need-2-Know (N2K) Update – Jan-Apr 2025
OAHN spring survey and lab data: Key results
There were 132 survey respondents from 38 counties, including primary care, referral, mobile and emergency practices. Survey responses reflected the typical spring rise in concerns about ticks and tickborne diseases, with a consistently high number of comments about both Lyme and Anaplasma seropositivity. There were several comments on “harder to resolve” cases of CIRDC and hemorrhagic diarrhea in dogs, and a good reminder from one respondent about the risk of dermatophytosis based on suspected spread to both a person and a pair of dogs from a subclinically infected rescue cat.
Stay alert! H5N1 influenza
Highly pathogenic avian influenza (HPAI) was considerably more active in early 2025 compared to last year, with six poultry premises, seven wild mammals (skunk, fox, mink, fisher) and numerous wild birds testing positive. Companion animal veterinarians should remain vigilant for H5N1 infections, particularly in cats presenting with severe acute neurological or respiratory signs or sudden death, especially (but not exclusively) if they have potential contact with other infected animals or raw diets /raw milk. Promote testing in suspect cases:
- Check with your lab to confirm they can identify H5 influenza strains
- Surveillance testing is also available for eligible cats through the OAHN AIV in feral cats surveillance project.
Rabies update: Foxes in the North
As of the end of April, seven rabid bats have been detected in Ontario so far this year, despite a surge in testing likely related to increased awareness following the fatal case of bat rabies in a person in Ontario last fall.
The MNR is continuing with its planned 2025 rabies baiting and control operations in southern Ontario, where no raccoon variant cases have been detected since 2023.
However, five red foxes from across northern Ontario have tested positive for rabies in 2025. This highlights the ever-present risk of Arctic fox variant rabies in arctic and sub-arctic habitats in Canada, where it is endemic across the geographic range of Arctic foxes (which also overlaps with the range of red foxes). Two recent cases of translocation of rabid dogs from northern to southern regions of Canada – a dog moved from Sanikiluaq NU to Winnipeg, and a dog moved from Umiujaq QC to Montreal – also clearly illustrate how risks in one region can have wide-reaching effects. As for dogs imported from high-risk countries for canine variant rabies, the risk period for rabies in any dog from the north is 6 MONTHS from their last possible exposure if they were previously unvaccinated.
OMAFA’s rabies response request form is the best way for veterinarians to reach OMAFA for assistance with risk assessments, sample submission and post-exposure management guidance for domestic animals. Find the form and lots of other useful guidance information on the Rabies: Information for Veterinarians webpage!
Feline disease cluster, Middlesex
An unusual cluster of disease in cats within a household was reported by an Ontario practitioner in late January 2025. A group of 4 kittens was unexpectedly dropped off on the owner’s property. The kittens were promptly isolated from the resident cats for several weeks until they had all been vaccinated and spay/neutered. When the cats finally were allowed to mix, one of the resident cats developed acute hydrothorax and another developed acute neurological signs. Both cats died, but no additional testing was performed. Several of the remaining cats then developed fever and signs of upper respiratory tract infection; while most recovered, one cat remained persistently lethargic, inappetent and febrile for two weeks. Based on the history of this group, the remaining sick cat was tested for H5N1 influenza, but was negative. Then a suspected granuloma was detected in the cat’s abdomen via ultrasonography, and an aspirate of the mass was PCR positive for FCV (FIP biotype). The cat was treated with GS-441524 and all clinical signs resolved J. Although it is highly unusual for FIP to spread directly within a group of cats, FIP would also be compatible with the signs in the first two cats that died.
If you see highly unusual cases or clusters of animals with potentially infectious diseases, you can share the details with OAHN quickly and easily via our companion animal disease reporting portal. All submissions are reviewed by members of the network team to detect any notable disease patterns and occurrences that should be communicated to Ontario veterinarians.
Ontario Lepto trends, 2023-2024
The latest update to the AAHA canine vaccination guidelines now lists leptospirosis vaccine as a core vaccine for most dogs, which is also consistent with the recently updated ACVIM consensus statement on leptospirosis in dogs. While the need for vaccination used to be based on a dog’s lifestyle and likelihood of exposure, nowadays even urban dogs with relatively limited outdoor access are not uncommonly affected by this very serious disease, due to its prevalence in periurban wildlife and in the environment in endemic regions like southern Ontario. Leptospirosis still tends to follow traditional seasonal trends, with cases being most common during cool wet weather (e.g. in the fall) which favours environmental persistence of the organism in urine-contaminated water. This can also be seen in the graph below of lepto PCR test results by month over the last two years, as submitted to OMAFA by Ontario veterinary diagnostic laboratories.
CAPCvet graphs
CAPCvet.org publishes monthly maps based on serological and fecal testing of select pathogens in dogs and cats by some of the major diagnostic labs in the US and Canada. Although the data only represent a fraction of the testing done in each area (estimated at approximately 30%), they still provide useful insight into local parasite activity. OAHN also posts graphs of these data for Ontario to help visualize trends over time. Check them out!
Echinococcus update
As routine fecal testing becomes more common in dogs in Ontario, cases of Echinococcus multilocularis (EM) continue to crop up. The latest three cases were in the regions of Peterborough, Middlesex and York. More information on EM cases across North America was recently published (Evason et al. 2024), and Dr. Andrew Peregrine provided a comprehensive update on EM in a recent webcast from CommuniVet.
Don’t-miss resources!
Check out these great resources from OAHN and others on current hot network topics!
- Hot on the heels of the latest AMU guidelines from ENOVAT and WSAVA comes their quick reference infographic: Five steps of canine acute diarrhea treatment
- ISCAID has updated its AMU guidelines for canine pyoderma (originally published in 2014), including sections on surface pyoderma, superficial folliculitis and deep pyoderma.
- A study on rabies antibody titres in imported dogs, partly funded by OAHN, is now available as an open access article (Belanger et al. ZPH 2025)
- Bites from dogs and cats are a risk for rabies transmission and can happen anytime. Keep the OAHN Veterinary Guidance for Domestic Animal to Human Bites Flowchart handy so you always know what to do (and not do) when a pet bites
- Get the latest updates on FIP treatment and drug availability in Canada from feline specialist Dr. Kelly St. Denis in the new webcast from CommuniVet – FIP: Treating the Untreatable
- PHO has just updated their 2025 HPAI infection prevention and control guidance for veterinary clinics, which was originally posted in June 2023.
- Watch for the OAHN quick reference for influenza A testing in companion animals, coming soon!
US canine imports
The CFIA remains in contact with the US CDC regarding US canine importation rules, which were set to be updated again in spring 2025. No additional changes have been made (yet) to the rules that came into effect last August.
Help us help you!
Have an idea for an infographic you’d like to see, or a podcast you’d like to hear? Email oahn@uoguelph.ca to let us know!
