H5N1 updates put cats and cattle surveillance back in focus

A Washington State outdoor cat has tested positive for H5N1, adding to mounting concern about feline spillover as bird flu continues to move across species. Scott Weese, DVM, PhD, highlighted the case in a February 2, 2026, Worms & Germs Blog update, alongside a separate development from the Netherlands, where follow-up testing on a Friesland dairy farm found H5N1 antibodies in five cows after a cat on the premises died and tested positive earlier in the investigation. Wageningen University & Research said the first Dutch cow identified had antibodies, but no detectable virus, suggesting prior infection rather than active shedding; all cattle PCR tests on the farm were negative. That makes this the first reported detection of H5N1 antibodies in cattle in Europe, and it raises fresh questions about how often cattle infections may be missed when animals are no longer actively shedding virus. (wormsandgermsblog.com)

Why it matters: For veterinary professionals, these updates reinforce two practical points: cats remain a sensitive sentinel species for H5N1 exposure, and cattle-associated infections may not always be obvious without targeted follow-up. Washington State guidance issued for companion animal veterinarians notes that domestic cats have been infected after exposure to infected birds, dairy environments, raw milk, and raw pet food, and advises clinicians to ask specifically about those risks when cats present with acute respiratory or neurologic disease. Broader feline surveillance may be warranted, especially as a recent University of Maryland review found 607 avian influenza infections across 12 feline species in 18 countries, with domestic cats making up most cases and 71.3% of PCR-confirmed infections proving fatal. (cms.agr.wa.gov)

What to watch: Watch for more serology-driven detections in cattle, updated surveillance guidance for cats on or near livestock operations, and any evidence clarifying whether the Dutch farm event reflects isolated spillover or limited cow-to-cow transmission. (wormsandgermsblog.com)