The United States continues to report widespread detections of highly pathogenic avian influenza H5N1 across multiple animal species and states. The USDA has confirmed infections in domestic cats, with the total number reaching 140 as of December 2024 in Contra Costa, California. New mammalian cases include a desert cottontail rabbit in Maricopa County, Arizona, and a red fox in Costilla County, Colorado, sampled as recently as May 29, 2025. Additional mammalian infections have been reported in muskrats and red foxes in New York.
The virus has also been detected in various wild bird species across numerous states, including multiple counties in Arizona, Maryland, Wyoming, New York, Iowa, Minnesota, Texas, Arkansas, Wisconsin, Missouri, Nebraska, South Dakota, Utah, and California. Notably, 26 H5 wild birds, including pigeons, were found in Maricopa, Arizona, and several predator birds such as hawks, owls, and vultures have tested positive in states like Wyoming, Colorado, and Pennsylvania. The USDA also reported the first new H5N1-infected dairy herd in weeks located in Arizona, marking the state's fifth and the country's 1,074th dairy herd affected. The Food Safety and Inspection Service (FSIS) has extended the H5N1 dairy cow testing program until September 30, 2025. In the UK, highly pathogenic avian influenza H5N1 has been confirmed in commercial poultry premises near Linton-on-Ouse, Wetherby, Easingwold in North Yorkshire, and near Glyn Ceiriog, Wrexham in Wales. Additionally, a clade 2.3.4.4b H5N1 virus was detected in a sheep in Great Britain in 2025. The ongoing animaldemic underscores the virus's extensive geographic spread and cross-species transmission, involving domestic animals, wildlife, and commercial poultry.
