Bird flu epicentre shifts from Asia to Europe and Africa as wild bird spread accelerates

For a quarter century, bird flu emerged from the same place: Asia. Scientists watched the virus circulate through poultry markets and wild bird populations across the continent, then spread outward in predictable waves. That pattern has broken. A new study published in Nature reveals that the epicentre of deadly avian influenza has shifted decisively toward Europe and Africa, driven by changes in how the virus moves through wild bird populations and evolves into new, more dangerous strains.

Researchers at the University of Hong Kong analysed confirmed outbreaks spanning 2005 to 2022, cross-referencing data from the Food and Agriculture Organization and the World Organisation for Animal Health while examining 10,000 viral DNA sequences. The findings are stark: while 2016 and 2017 saw new outbreaks originating in China, two critical developments marked a turning point. In 2020, a novel H5 virus emerged in African poultry. Two years later, another new H5 strain appeared in European wild birds. These were not echoes of Asian variants. They were new evolutionary branches, born in different continents.

The latest iteration of H5N1—the highly pathogenic variant—has become the most infectious bird flu on record. One infected bird can transmit the virus to as many as 100 others through faeces, mucus, blood, and saliva. The 2022 European outbreak was the worst the continent had ever seen, and from there the virus spread globally. It now exists on every continent except Oceania and Antarctica. The death toll among birds has shattered records. Domestic poultry flocks have been decimated. Wild bird populations have suffered losses that researchers estimate in the millions, though the true number remains unknowable—most carcasses are never found or counted. The virus has also jumped into mammals, a development that alarmed epidemiologists who thought such leaps unlikely.

Human infection remains rare but serious. Since 2003, the World Health Organization has documented 873 confirmed cases of H5N1 in people, resulting in 458 deaths. Nearly all were linked to direct contact with infected poultry. Human-to-human transmission has not been documented, which is the only reason the virus has not triggered a pandemic. But the sheer number of infected birds globally means the risk of human exposure continues to rise.

The researchers point to a fundamental problem: only 0.2 percent of confirmed bird flu cases have been genetically sequenced. This means the scientific community is essentially flying blind, unable to track how the virus is changing or predict where new strains will emerge. Africa's surveillance infrastructure is particularly weak, the authors note, leaving an entire continent vulnerable to undetected viral evolution. The shift in the outbreak epicentre underscores why this matters. If new variants are emerging in Africa and Europe, scientists need real-time genetic data to understand them.

Traditional disease control—mass culling of infected flocks—once worked because outbreaks were contained and localized. That strategy is failing now. The virus has become so entrenched in wild bird populations that culling domestic poultry alone cannot stop its spread. In the UK, government data shows more than 99 percent of poultry infections trace back to wild birds, not other farms. The disease now moves along ancient migratory routes. Birds flying the east Atlantic and Pacific flyways carry the virus to regions that have never encountered it before, seeding outbreaks in naive populations with no immunity.

The spread within the poultry industry itself remains tied to human decisions—how birds are transported, where they are traded, which farms are connected to which supply chains. But in the wild, the virus follows the calendar and the compass. As long as migratory birds carry it, as long as it continues to evolve in wild populations, the epicentre will keep shifting. The question now is whether surveillance can keep pace with the virus's movement, or whether the next dangerous strain will emerge undetected.