Global H5N1 Avian Flu Pandemic Expands: 39 Countries Affected, Unprecedented Spread in Poultry and Wildlife

AVIAN FLU WATCH: GLOBAL H5N1 TRACKER Welcome to Avian Flu Watch, your weekly update on the global spread of highly pathogenic avian influenza H5N1. I'm your host, and today we're tracking a pandemic that has fundamentally reshaped animal health worldwide. Let's start with the numbers. In 2022 alone, 67 countries across five continents reported H5N1 outbreaks in poultry and wild birds, resulting in over 131 million domestic poultry deaths or cullings. The situation has only intensified. In 2023, an additional 14 countries, mostly in the Americas, reported outbreaks. According to the FAO, 1,391 outbreaks have been reported in 39 countries since late December 2025. The cumulative losses since 2005 have surpassed 633 million poultry worldwide. Now let's examine the geographic hotspots. Risk mapping reveals severe ecological suitability for H5 circulation in Europe, Asia, and the Americas. In Asia, countries including South Korea, Japan, Vietnam, Thailand, and the Philippines show persistently high suitability. European nations such as France, the Netherlands, Germany, Italy, Ukraine, and Poland are identified as high-risk regions. In Africa, Nigeria and South Africa demonstrate environmental conditions favorable for local virus circulation. The Americas present a concerning picture, with marked increases in predicted suitability post-2020, particularly in the Great Lakes region of North America and throughout South America, including Brazil, Colombia, and Peru. The North American situation has shifted dramatically since 2021, when the virus reentered the continent after a decade of relative freedom. Over 10,000 wild birds representing more than 160 unique North American species have tested positive for HPAI H5 or H5N1. In 2025, nine countries in the Americas confirmed 508 poultry outbreaks, with thousands of detections in wild birds. Regarding transmission patterns, a critical shift emerged with the H5N1 clade 2.3.4.4b variant, which demonstrated increased capacity to infect mammals. Over 200 mammalian species have been infected, including dairy cattle, cats, minks, and seals. Dairy cattle infections in the United States present a new epidemiological puzzle, manifesting as mastitis rather than pneumonia, with high viral loads in milk. Human infections remain sporadic, with 26 cases reported between January and August 2025, primarily causing conjunctivitis rather than respiratory disease. Wild bird migration patterns continue driving global dissemination. Post-2020 data reveals a significant shift in affected bird species diversity, with sea birds increasingly impacted. Urban and built-up areas show strong correlation with H5 occurrences, though this association has actually decreased from 54.5 percent before 2020 to 39.3 percent post-2020, suggesting expanding geographic range. Critical concerns include emerging variants of concern, particularly clade 2.3.4.4b, which binds to both avian and mammalian receptors. Key adaptive mutations like HA-Q This content was created in partnership and with the help of Artificial Intelligence AI.