H5N1 Bird Flu Outbreak Continues with 71 Human Cases Across US Dairy and Poultry Sectors in 2025

BIRD FLU BULLETIN: DAILY H5N1 UPDATE Good evening. This is your Bird Flu Bulletin for Monday, December 1st, 2025. I'm bringing you the latest developments on the H5N1 avian influenza situation affecting the United States and beyond. TOP STORIES Our first story involves the latest surveillance data from the CDC and USDA. As of today, there are 71 confirmed and probable human cases of H5N1 in the United States since the outbreak began in March 2024. Of these cases, 41 were exposed to infected dairy herds, 24 to commercial poultry operations, three to other animal exposures, and three cases remain with unknown sources. The CDC confirms that no human-to-human transmission has been identified despite extensive contact investigations. Second, the animal health situation continues to present challenges across the nation. The USDA reports that 989 dairy herds across 17 states have confirmed H5N1 infections in dairy cattle. Additionally, detections span 336 commercial poultry flocks and 207 backyard flocks, with more than 90 million birds affected nationwide. Wild bird surveillance has detected over 13,000 infected birds across 51 jurisdictions. Third, recent case patterns show that the last confirmed human illness onset occurred in February 2025. Four cases resulted in hospitalization, with one fatal outcome reported in Louisiana. The CDC notes that 94 percent of confirmed cases experienced mild illness, though healthcare providers remain vigilant for severe presentations. EXPERT PERSPECTIVE We spoke with epidemiological officials monitoring the outbreak who emphasized that while human-to-human transmission remains absent, the persistent circulation of H5N1 in dairy cattle and poultry warrants continued surveillance. They noted that most affected individuals worked occupational roles involving direct animal contact, particularly dairy workers and poultry culling operation employees. The absence of neuraminidase inhibitor resistance provides some reassurance regarding treatment options if additional cases emerge. CASE COMPARISON AND GUIDANCE Comparing our numbers to recent weeks, we have maintained 71 total confirmed cases since February 2025 brought no new human infections. The CDC continues to emphasize that the immediate risk to the general public remains low. However, health authorities maintain enhanced surveillance protocols and recommend that individuals with occupational exposure to infected animals implement strict hygiene measures and use appropriate personal protective equipment. LOOKING AHEAD Tomorrow's expected developments include ongoing monitoring of dairy herds through the national milk testing strategy that began in December. The USDA continues its mandate requiring testing of milk samples across California, Colorado, Michigan, Mississippi, Pennsylvania, and Oregon. We anticipate routine surveillance updates and continued monitoring of wild bird populations heading into winter months. Health officials will likely provide upda This content was created in partnership and with the help of Artificial Intelligence AI.