Episode Details

You’re listening to “H5N1 Global Scan: Avian Flu Worldwide.”

Today we’re taking a fast tour of how highly pathogenic H5N1 avian influenza is reshaping animal health, trade, and pandemic preparedness across the globe.

Since 2020, H5N1 clade 2.3.4.4b has driven an unprecedented panzootic, with outbreaks on every continent except Australia, according to summaries compiled by the World Organisation for Animal Health and reviewed in the 2020–2025 H5N1 outbreak overview. Wildlife, poultry, and a growing list of mammals – from sea lions to dairy cattle – have been hit hard, disrupting ecosystems and food systems alike.

In the Americas, the Pan American Health Organization reports thousands of H5N1 outbreaks in birds since 2022, and dozens of human infections, most linked to direct contact with sick poultry or, in the United States, infected dairy cows. The US Centers for Disease Control and Prevention notes more than 70 confirmed human H5 infections since 2024, almost all mild and with no sustained human‑to‑human transmission so far.

In Europe and Central Asia, the European Centre for Disease Prevention and Control describes repeated waves in poultry and wild birds and scattered human cases, mostly in people with close animal exposure. Africa has seen major poultry losses and culling campaigns in North and West Africa, while under‑resourced surveillance raises concern that human cases may be underdetected. In Asia, WHO‑reported clusters in Cambodia, Bangladesh, India, and China highlight continuing spillover risk in smallholder poultry systems and live bird markets. In Oceania, strict biosecurity has limited spread, but authorities remain on high alert.

Globally, the Food and Agriculture Organization tracks nearly a thousand recent animal outbreaks in dozens of countries, emphasizing the economic shock: mass culling of poultry, egg and meat price spikes, and trade restrictions that hit export‑dependent producers. Outbreaks in South American wildlife and seal colonies have also triggered tourism and fisheries concerns.

On coordination, the WHO–FAO–WOAH “One Health” framework is driving joint surveillance across humans, livestock, wildlife, and the environment. WHO risk assessments currently rate the public health risk of H5N1 to the general population as low, but higher for people with occupational exposure, and call for continued genomic monitoring and rapid sharing of virus samples.

Research efforts are accelerating. According to recent scientific reports, sequencing of clade 2.3.4.4b shows adaptation that allows infection of a broader range of mammals, but so far without the sustained human‑to‑human transmission that would signal a looming pandemic. Experimental infection studies, environmental sampling on farms, and serological surveys in high‑risk workers are refining our understanding of how, and how often, the virus crosses species barriers.

On vaccines, WHO’s global influenza program and its partners have updated candidate vaccine viruses for H5, and several manufacturers have dose‑sparing, adjuvanted H5N1 formulations that could be scaled if needed. Some countries, particularly in Europe and Asia, are beginning targeted poultry vaccination campaigns, while others, like the United States, still prioritize stamping out outbreaks through culling and strict movement controls.

National approaches vary widely. The European Union leans on regionally harmonized surveillance and, increasingly, poultry vaccination. Several Asian countries combine live bird market controls, periodic closures, and risk communication in rural communities. In the Americas, Canada and the US emphasize intensive farm biosecurity, large‑scale testing, and occupational protections for farm and culling workers. Low‑ and middle‑income countries often struggle to match these measures, highlighting a need for more funding, technology transfer, and vaccine access.