H5N1 updates put cats and Dutch cattle back in focus

Two new H5N1 signals, one from a dead cat in Washington state and one from a Dutch dairy farm, underscore how uneven but persistent the virus’s mammalian spillover pattern has become. In a February 2, 2026, update, Worms & Germs author Scott Weese highlighted a presumed fatal H5N1 infection in an outdoor cat in Washington and linked it to a separate development in the Netherlands, where one dairy cow on a farm connected to feline H5N1 cases was found to have antibodies indicating past exposure. (wormsandgermsblog.com)

The Dutch finding builds on an earlier cluster involving kittens on a dairy goat farm in the Netherlands, where H5N1 infection was suspected after multiple kitten deaths. Subsequent investigation traced one affected cat to a dairy farm and prompted cattle testing. Wageningen University & Research reported on January 23, 2026, that one cow had antibodies against H5N1, the first such finding in European cattle, but none of the cows tested had detectable virus, and milk testing did not show active virus either. The European Centre for Disease Prevention and Control said the finding did not change its risk assessment, noting no exposed people developed symptoms and no evidence of onward spread had been found. (wur.nl)

That distinction matters. In the Netherlands, investigators are talking about antibodies, not confirmed active infection. As Weese noted, that could mean the cow was infected previously, cleared the virus, and never became visibly ill, though he also cautioned that false positives are always a consideration with rare outcomes and antibody testing. Dutch authorities likewise emphasized that the situation is not comparable to the U.S. dairy outbreak because no virus particles have been detected so far in Dutch dairy cattle or milk. (wormsandgermsblog.com)

The cat side of the story is more familiar, and more concerning for small-animal practice. Cats have repeatedly shown high susceptibility to H5N1 through exposure to infected birds, contaminated raw poultry, and raw milk. A 2025 systematic review in Open Forum Infectious Diseases identified 607 feline avian influenza cases across 18 countries from 2004 to 2024; among 423 PCR-confirmed infections, 71.3% were fatal. The authors warned that domestic cats may represent a pathway for zoonotic spillover because they live in close contact with people and are not routinely surveilled. (academic.oup.com)

Other recent evidence supports that concern. CDC researchers described domestic cat infections after ingestion of raw milk contaminated with H5N1, including two deaths and one surviving cat that shed virus in urine. CDC guidance for veterinarians says H5N1 should be considered in cats with acute neurologic disease or respiratory illness when there’s a history of exposure to wild birds, raw poultry, raw meat, or unpasteurized dairy products. FDA has also warned that felines are particularly sensitive to H5N1 and that foodborne exposure, especially through uncooked meat or unpasteurized milk, has been implicated in multiple investigations. (wwwnc.cdc.gov)

Expert commentary around feline H5N1 has become more pointed over the past year. University of Maryland researchers said surveillance of domestic cats is “urgently needed” as reports have accelerated since 2023, particularly with clade 2.3.4.4b. CIDRAP’s coverage of the review emphasized that infections in cats have risen alongside the broader mammalian spread of H5N1, and that exposure routes now appear broader than simple bird predation alone. Those observations align with International Cat Care’s warning that preventive advice for pet parents should include avoiding raw poultry and unpasteurized milk, particularly as awareness of feline risk still lags behind awareness of poultry and cattle risk. (today.umd.edu)

Why it matters: For veterinary professionals, these updates sharpen the need for exposure-based triage, PPE decisions, and client communication. In cats, H5N1 can look like a neurologic emergency, a respiratory case, or sudden death, and the exposure history may involve outdoor access, barn environments, wildlife contact, or diet. In food-animal medicine, the Dutch case is a reminder that surveillance may find evidence of exposure before disease is clinically obvious, which raises questions about how widely cattle should be monitored outside known outbreak zones. Even when public health risk remains officially low, veterinary teams are often the first to connect the dots across species. (cdc.gov)

What to watch: The next key signals will be whether Dutch follow-up testing uncovers any active infection in cattle, whether additional feline cases are tied to farms or food exposures, and whether surveillance guidance for cats and cattle becomes more formalized in response. (ecdc.europa.eu)