Global H5N1 Outbreak Intensifies: Millions of Birds Affected Across 38 Countries with Rising Transmission Risks

Avian Flu Watch: Global H5N1 Tracker This week, we are tracking a highly dynamic H5N1 landscape, with new animal and occasional human infections reshaping global risk. Globally, the UN Food and Agriculture Organization reports nearly one thousand H5N1 and related highly pathogenic avian influenza outbreaks in animals across 38 countries since late September, affecting millions of birds in commercial and backyard settings. The virus remains entrenched in wild bird reservoirs on every continent except Antarctica, sustaining a steady baseline of transmission. Geographically, three hotspots stand out. In Europe, the European Commission and the European Centre for Disease Prevention and Control describe a sharp uptick in H5N1, with more than 500 poultry farm detections so far this year and over 2,800 wild bird cases, concentrated in France, Germany, the United Kingdom, and the Iberian Peninsula. In North America, the US Department of Agriculture has confirmed H5N1 in commercial and backyard flocks in dozens of states over the last month, totaling more than 4 million birds culled, while wild bird positives continue along the Atlantic and Mississippi flyways. In Asia and Africa, Lanvira’s Flock Watch reports new H5N1 outbreaks in India, Iraq, Nigeria, and South Africa, including single farms holding more than 150,000 birds. Imagine a global line chart: on the x axis, the last 12 months; on the y axis, weekly H5N1 detections in animals. We see a winter 2024–25 peak, a summer trough, and now a renewed climb approaching or surpassing last season’s highs in Europe and North America. A companion bar chart, broken down by region, shows Europe leading in poultry cases, North America in wild bird and mixed-species detections, and South America plateauing after its first explosive wave. Cross-border transmission is driven largely by migratory birds. A Nature analysis of the North American epizootic shows wild birds as the central vectors linking outbreaks across flyways, while a recent South American phylogeographic study demonstrates H5N1 moving from Chile and Argentina into Uruguay and Brazil via seabirds and marine mammals, then back into inland poultry. These data highlight how virus lineages hop seamlessly between countries and host species, challenging traditional border-based control. There have been notable containment successes. The United Kingdom’s animal health authorities continue to rapidly impose 3 kilometer protection and 10 kilometer surveillance zones around each new farm detection, with targeted culling that has ended several regional outbreaks. In the United States, aggressive depopulation and enhanced biosecurity have stopped spread beyond affected dairy herds and poultry premises in multiple states. But there are also failures. According to Infection Control Today, H5N1 has now impacted poultry in all 50 US states, requiring the loss of more than 175 million birds since the start of the epizootic, underscoring gaps in farm-level biose This content was created in partnership and with the help of Artificial Intelligence AI.