Avian influenza is sweeping the globe and infecting dozens of species. Advocates of an approach called One Health are calling for broad surveillance of wildlife, livestock and pets. In the southwestern United States in the early weeks of 2024, a large-animal veterinarian pulled up to a dairy farm on his usual rounds and was greeted by an odd absence. The barn cats who normally came trotting out to meet his truck were nowhere in sight.
Over the next few weeks, at dairies across Texas and New Mexico, cows started to get sick. They were losing their appetites and producing less milk than usual — and what little they did produce was thick and gluey. Deaths of birds such as crows and pigeons were also being reported. And then there were the barn cats. They were disappearing or dying suddenly, after becoming blind or unable to walk (see ‘Is a lack of curiosity killing the cats?’).