H5N1 Bird Flu Remains Stable: Global Cases Unchanged with Low Human Transmission Risk in 2025

Bird Flu Bulletin: Daily H5N1 Update Monday, September 1, 2025 Good afternoon! You’re listening to Bird Flu Bulletin: Daily H5N1 Update for Monday, September 1, 2025. Top Stories 1. The Centers for Disease Control and Prevention reported that the global tally of human H5N1 cases has remained unchanged in the last 24 hours, holding at 26 since January with 14 in Cambodia, and eight resulting in deaths. In the United States, no new human cases have been detected since mid-February. International health agencies continue to flag Cambodia as a hotspot, especially for those with direct contact with poultry according to the CDC. 2. Despite steady human case numbers, high pathogenic H5N1 activity in animals persists. The USDA revealed ongoing outbreaks among wild birds and poultry across multiple states, including recent detections in feral and domestic cats. The organization stresses that cats are typically dead-end hosts and pose minimal onward risk, but their involvement highlights the broad mammalian reach of H5N1 in 2025 according to USDA and World Organisation for Animal Health reporting. 3. The Food and Agriculture Organization’s latest update confirms sporadic H5N1 spillover into mammals and highlights an uptick in farmers and veterinarians seeking booster vaccinations for livestock and poultry. China’s H5-Re14 vaccination in chickens continues to show efficacy, helping limit outbreaks in Asia. Globally, surveillance is being strengthened as animal cases rise. Case Numbers In the United States, confirmed human H5N1 cases since March 2024 stand at 70 with one fatality, a number that remains stable this week as per Nature and CDC sources. Globally, total cases have plateaued at 26 since January 2025, with no evidence of person-to-person spread, according to both CDC and WHO. Testing and monitoring of exposed individuals continue. New Guidance Today, CDC reiterated their position that public health risk remains low for most Americans but urges caution for poultry and livestock workers. The agency reminds producers to increase biosecurity measures, limit contact with sick or dead animals, and report unusual health events in herds and flocks. The World Organisation for Animal Health recommends heightened vigilance in veterinary clinics, especially where cats and other mammals have shown infection. Expert Interview For today’s update, we spoke with Dr. Pallavi Upadhyay, an infectious disease specialist: "The animal outbreaks this year underscore the need for rigorous surveillance. While no sustained human transmission has been seen, those exposed to infected animals must take precautions. Our lab’s experimental mRNA vaccine shows promise in animal trials, but broad human rollout is still a step away.” Looking Ahead Tomorrow, expect updated monthly flu surveillance data from CDC, which will likely incorporate the latest targeted H5 testing and exposure numbers. International teams are expanding surveillance in Southeast Asia and U.S. a This content was created in partnership and with the help of Artificial Intelligence AI.