Health officials in the United States have issued repeated warnings about the H5N1 bird flu virus, stressing the need for continued monitoring. New human cases have decreased sharply since early 2024, but experts remain concerned about the drop in testing. The Centers for Disease Control and Prevention (CDC) last confirmed human infections in February 2025. Most earlier cases were linked to dairy and poultry farmworkers. California reported 38 human cases, with no new cases after January 14. One person did not survive the virus, while most others had mild symptoms.

Officials say the lower number of cases may be due to wild bird migration patterns. However, other experts suggest that reduced testing could be hiding mild infections, especially among vulnerable groups. Some believe that fear of deportation among immigrant workers might stop people from seeking medical help. Experts are also concerned about a drop in staffing at agencies like the U.S. Department of Agriculture and the Food and Drug Administration, which may affect testing and reporting. Researchers from Texas A&M University and the University of Maryland are studying past exposure in dairy workers and cats. Over 120 domestic cats in the U.S. have tested positive, some of which did not survive the virus. Experts are calling for stronger surveillance to avoid missing infections and to ensure preparedness in case the virus spreads more widely in the future.