Avian flu is adapting to spread to marine mammals

The recent avian flu strain has adapted to spread between birds and marine mammals, posing a threat to wildlife conservation, researchers found.

In a study published in Emerging Infectious Diseases, researchers used genomic testing to characterize the highly pathogenic avian influenza virus H5N1 in marine wildlife in South America. They found the virus was nearly identical in samples of four sea lions and a seal, as well as a tern.

“This confirms that while the virus may have adapted to marine mammals, it still has the ability to infect birds,” said first author Agustina Rimondi, a virologist from the National Institute of Agricultural Technology in Argentina. “It is a multi-species outbreak.”

The virus has affected wild bird populations and domestic poultry around the world. Since 2022, H5N1 in South America has killed at least 600,000 wild birds and 50,000 mammals, including elephant seals and sea lions in Argentina, Chile and Peru.

Read more from the University of California Davis.