Bird flu spreads from Asia to Africa and Europe

An international team of scientists studied epidemiological data and more than 10,000 viral genomes since 2005 and concluded that the epicenter of H5 avian influenza has shifted from Asia to Africa and Europe.

The study’s authors highlight the geographic expansion of epicenters of highly virulent H5 viruses beyond their traditional Asian regions into Europe and Africa.They also warn that the persistence of these viruses in wild birds has increased, to their benefit geographical distribution and expanded the range of infections to avian species, including livestock, accelerating their ability to evolve.

Scientists from China, Egypt, France, Australia, the United Arab Emirates and the United States nature.

They concluded that the epicenter of bird flu has shifted from Asia to several regions in Europe and Africa, with variants emerging on both continents that are, in some cases, highly virulent. Between 2020 and 2022, new lineages emerged in these areas, and the evolution of these lineages is as follows: genetic recombination

Like other viruses, they circulate with less pathogenic virus variants.

According to the authors, the persistence of avian influenza in wild bird populations may be driving the evolution and spread of new strains.

To reach this conclusion, they used epidemiological data collected by the Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health from 2005 to 2022 to analyze the origins and changing trends of highly pathogenic avian H5 epidemics, and Analysis of more than 10,000 complete viral genomes.

After analyzing the genomes, they found that the first major outbreak originated in China in 2016/17, while two new H5 viruses discovered between 2020 and 2022 emerged from African and European bird populations, which would It shows that the epicenter of the epidemic has undergone major changes. Bird flu spread from Asia to these continents.

The study “proves something that was already suspected: The role of wild birds “The highly pathogenic avian influenza (HPAI) H5N1 virus is spreading globally, causing massive deaths of wild and domestic poultry in many countries around the world, including Spain,” said Gustavo del Real, a researcher at the National Institute of Agricultural Research and Technology. and Alimentaria (INIA-CSIC) in a statement published on the Scientific Media Center platform (SMC Spain).

“Since the outbreak began in 2021, it has also put a variety of mammals at risk, including some sporadic cases of human infection. Nonetheless, H5N1 virus first appeared in China In 1996, outbreaks of the H5 subtype evolved strain have not stopped since then, mainly in Asia. “This study sheds light on the origin and potential evolution of the highly pathogenic H5N1 virus responsible for the 2021 avian influenza pandemic.”

Through phylogenetic and epidemiological analysis H5N1 virus cycle through Poultry and game birds During 2021-2022, this new H5 subtype lineage was demonstrated to have evolved in wild birds in Europe from previous H5 HPAI viruses that were introduced in Asia during 2016-17 and 2020-21 and Africa caused animal epidemics.

These New H5N1 virus The highly virulent virus evolved during global spread through recombination with other low-pathogenic avian influenza (LPAI) strains from wild and domestic poultry.

In summary, “the authors advocate the urgent implementation of systematic control measures for domestic and wild birds to limit the emergence of new epizootics and prevent their spread to mammals, including humans.”

Nature https://doi.org/10.1038/s41586-023-06631-2