Welcome to H5N1 Global Scan: Avian Flu Worldwide, a Quiet Please production. I’m your host, and today we’re taking you inside the latest wave of highly pathogenic avian influenza circling the globe, with vital updates from every continent, major science breakthroughs, and what it all means for public health and global trade.

Let’s start with a global snapshot. Since 2020, H5N1—a subtype of avian influenza—has swept every continent except Australia, according to recent analyses. Outbreaks have devastated wild bird and poultry populations, and increasingly, mammals—including sea lions, seals, and even livestock. For the first time, H5N1 reached Antarctica in late 2023, sparking fears for vulnerable wildlife that have never faced avian flu. In South America alone, over 600,000 wild birds and 50,000 mammals are estimated to have died since 2022, with seal pup mortality rates reaching 96% in some Argentine regions. Meanwhile, in North America, the United States has culled tens of millions of chickens, triggering egg shortages and export bans. Europe has seen mass die-offs in cranes and repeated outbreaks on poultry farms, while Asia and Africa continue to report both animal and human cases.

The human toll remains concerning but, so far, contained. Since January, at least 26 confirmed human cases have been reported globally, with infections occurring after close contact with infected birds or mammals. The U.S. Centers for Disease Control and Prevention notes 70 cases in the U.S. since 2024, mostly in workers exposed to dairy cattle or poultry. Fatalities have been reported in the United States, Mexico, India, and Cambodia, among others, with Cambodia experiencing a recent cluster in children. The World Health Organization reports that, historically, nearly half of all confirmed H5N1 human cases have been fatal, highlighting the virus’s continued risk.

Scientific research is accelerating. The WHO and FAO are tracking genetic changes in the virus, which is evolving rapidly, in some cases mixing genes from older and newer strains, creating new challenges for vaccine development and pandemic preparedness. The main virus driving this outbreak—H5N1 clade 2.3.4.4b—has shown an unsettling ability to infect a broader range of species, including mammals, according to virology reports. This genetic shuffling, or reassortment, has led to new variants, complicating both surveillance and vaccine matching. In Southeast Asia, for example, the FAO has documented reassortant viruses with genes from both older and current lineages implicated in human cases.

International coordination is ramping up. The WHO and FAO are leading efforts to improve early detection, share genetic data, and coordinate rapid response, but gaps remain. Cross-border trade has been disrupted, with countries imposing export bans on poultry and poultry products, as seen in Argentina and the Philippines. The Pan American Health Organization reports that 19 countries in the Americas have logged over 5,000 outbreaks since 2022, many in wild bird populations along major migration flyways. The risk of further spread via migratory birds and international trade is real, and experts urge stricter biosecurity and surveillance, especially in regions where animal and human populations live in close proximity.

Vaccine development is a top priority, but progress is uneven. Several countries are testing bird and livestock vaccines, while human vaccine candidates are in development. Yet, matching vaccines to circulating strains is a moving target. The global vaccine landscape is fragmented—some nations prioritize mass culling and biosecurity, while others, like China, invest heavily in poultry vaccination. The European Union, meanwhile, is exploring ring vaccination around outbreak zones. These different approaches reflect varying risk assessments and resource levels, but also highlight the need for a harmonized global strategy.Back to Episodes