Elephant Seal Colony Declines One Year After Avian Flu Outbreak
Study Chronicles First Report of ‘Bird Flu’ Transmission Between Marine Mammals
The sounds of barking elephant seals are again in the air along the breeding grounds of Península Valdés, Argentina—but it’s quieter. Roughly a year after a massive outbreak of H5N1 highly pathogenic avian influenza killed more than 17,000 elephant seals, including about 97% of their pups, scientists estimate that only about a third of the elephant seals normally expected here returned.
A study, published today in the journal Nature Communications and co-led by UC Davis and the National Institute of Agricultural Technology (INTA) in Argentina provides evidence of mammal-to-mammal transmission during the 2023 outbreak. It found that H5N1 spread efficiently among marine mammals. The outbreak in elephant seals was a stepping stone amid the first transnational spread of the virus in these species, extending across five countries in southern South America.
The study’s genomic analysis further found that, upon entering South America, the virus evolved into separate avian and marine mammal clades, which is unprecedented.
Read the full press release Lea este comunicado de prensa en Español.