The United States managed to curb a bird flu outbreak in 2025 after its first known human death from the virus, ending the public health emergency response by July. Despite progress, experts warn that the H5N1 strain remains a threat to animals and could still pose risks to humans. Efforts focused on testing, vaccination research, and biosecurity measures helped reduce cases in livestock and people.
The year 2025 began with alarm in the US when a person in Louisiana with underlying health conditions died from H5N1 in January, marking the nation's first known bird flu fatality. This subtype of avian influenza, which first appeared in poultry in China in 1996 and reemerged globally in 2021, has devastated bird populations and spread to mammals like foxes, seals, and cats. Worldwide, it has killed nearly half of the almost 1,000 known human cases since 2003, though milder infections often go unreported.
H5N1 reached US dairy cows in March 2024, infecting over 1,080 herds across 19 states and raising fears of adaptation for human-to-human transmission. From February 2022 to mid-December 2025, the virus sickened at least 1,950 poultry flocks, leading to the culling of nearly 200 million birds. Human cases totaled 71 by December 2025, with most linked to dairy or poultry exposure; symptoms were generally mild, like eye redness, and all recovered except the initial death.
A separate incident occurred in November 2025, when a man in Washington state died from the related H5N5 strain after poultry contact, though no further human cases emerged. The last H5N1 positive test in humans was in February 2025. Infections in dairy cattle dropped sharply, with only two herds testing positive from November to mid-December.
Key responses included the USDA's National Milk Testing Strategy launched in December 2024, mandating raw milk samples for surveillance. In February 2025, the USDA committed $1 billion to poultry protection, emphasizing vaccine research and defenses against wild birds, which introduce most farm infections. These measures, plus seasonal factors, likely contributed to the decline, allowing the CDC to end its emergency response—started in April 2024—in early July 2025.
"It is still a pandemic in [non-human] animals," says Meghan Davis at Johns Hopkins University in Maryland. "And the virus is no less deadly now than it was before." She adds, "Testing is absolutely central to any control strategy." While poultry detections rose over 130 percent from September to October 2025 amid migration, human cases stayed low. Davis remains cautious: "I am encouraged that we’ve seen a declining number of cases, but I think there is still more that we need to do." The CDC assesses public risk as low but continues monitoring.
