The sounds of barking elephant seals are again in the air along the breeding grounds of Pen铆nsula Vald茅s, Argentina鈥攂ut it鈥檚 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.
Lea este comunicado de prensa en Espa帽ol.
鈥淚t鈥檚 beautiful to walk the beaches now and hear elephant seals again,鈥 said Marcela Uhart, director of the Latin America Program at the 完美体育 Karen C. Drayer Wildlife Health Center within the 完美体育 School of Veterinary Medicine. 鈥淎t the same time, we鈥檙e walking among piles of carcasses and bones, and seeing very few elephant seal harems, so it鈥檚 still disturbing.鈥
in the journal Nature Communications and co-led by 完美体育 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鈥檚 genomic analysis further found that, upon entering South America, the virus evolved into separate avian and marine mammal clades, which is unprecedented.
鈥淲e鈥檙e showing the evolution of H5N1 viruses that belong to genotype B3.2 over time since their introduction in South America in late 2022,鈥 said virologist and co-leading author Agustina Rimondi of INTA and currently also with Robert Koch Institute. 鈥淭his virus is capable of adapting to marine mammal species, as we can see from the mutations that are consistently found in the viruses belonging to this clade. Very importantly, our study also shows that H5 marine mammal viruses are able to jump back to birds, highlighting the need for increased surveillance and research cooperation in the region.鈥