H5N1 updates raise fresh concerns for cats and cattle

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H5N1 influenza surveillance is continuing to widen the map of concern, with one update centered on a fatal cat case in Washington state and another on a Dutch dairy cow with evidence of prior infection. Taken together, the cases don’t show a new confirmed transmission route on their own, but they do reinforce two themes veterinarians have been hearing for months: cats are a consistent spillover species, and cattle-related H5N1 questions are no longer confined to the United States. (nationaltoday.com)

The Washington case involved an outdoor cat in Grant County that tested positive for H5N1 after dying, according to state reporting summarized in late January 2026. That fits a growing body of evidence that cats can be infected through contact with wild birds, farm environments, raw milk, or contaminated raw pet food. Washington state’s companion-animal guidance, issued in February 2025 after separate raw-food-linked feline infections, advises veterinarians to ask pet parents specifically about raw diets and raw milk and notes that most domestic cat cases have been linked to infected dairy or poultry farms, with a smaller number tied to contaminated raw animal products. (nationaltoday.com)

The Netherlands update is notable because it appears to be Europe’s first reported dairy cow with H5N1 antibodies. Wageningen University & Research said the cow was investigated after avian influenza had already been confirmed in a cat on the same Friesland farm. Testing found no viral RNA in sampled cattle, but one cow had antibodies indicating previous exposure. Investigators said that cow had mastitis and reduced milk yield in mid-December 2025, then recovered. Milk from the sick period did not enter the food chain, and the farm’s milk was restricted to pasteurized products while authorities continued testing. (wur.nl)

Dutch and European officials have been careful to distinguish this event from the U.S. dairy outbreak. Wageningen said no virus particles were found in the Dutch cow or its milk, meaning there was no evidence of active shedding at the time of testing. ECDC likewise said no other cows on the farm had tested positive for the virus, no exposed people had developed symptoms, and its public-health risk assessment remained unchanged: low for the general population, and low to moderate for people with occupational exposure to infected animals or contaminated environments. (wur.nl)

On the feline side, the broader literature supports the concern behind both updates. A 2025 systematic review of avian influenza in felines identified 607 infections across 18 countries from 2004 to 2024 and estimated a 71.3% case fatality rate among reported RT-PCR-confirmed feline infections. The authors and subsequent industry coverage argued that cats deserve closer surveillance because they can be exposed in homes, shelters, farms, and rural settings, often through birds or raw poultry products. International Cat Care has also urged preventive steps including avoiding raw poultry and unpasteurized milk, reflecting the same risk factors veterinarians are now seeing repeatedly in case investigations. (pmc.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, the practical message is less about novelty than pattern recognition. Cats with sudden neurologic signs, respiratory disease, or rapid decline, especially those with outdoor access, farm exposure, or a history of raw food or raw milk consumption, warrant a careful H5N1 exposure history and coordination with animal health authorities on testing. The Dutch cow finding also broadens the surveillance conversation: even without evidence of active viral shedding, serologic evidence in European cattle suggests clinicians and herd veterinarians should stay alert for subtle production changes, mastitis, and cross-species signals on mixed-species farms. (cms.agr.wa.gov)

There’s also a communication challenge for clinics. Pet parents may still associate H5N1 mainly with birds, but the accumulating cat cases, raw-food-linked infections, and dairy-farm links mean veterinarians increasingly need to explain that exposure can happen indirectly. That includes contaminated food products, infected milk, or environmental contact rather than obvious bird predation alone. Washington’s guidance explicitly says there is no evidence of cat-to-cat or cat-to-human transmission so far, but it also advises monitoring exposed people after contact with infected cats, showing how companion-animal cases can quickly become a One Health issue. (cms.agr.wa.gov)

What to watch: The next key signals will be whether Dutch follow-up testing finds additional seropositive or PCR-positive cattle, whether more European farm cats or livestock are linked to H5N1, and whether veterinary guidance evolves around testing thresholds, raw diet counseling, and surveillance in companion animals and dairy herds. (wur.nl)