Practical guide for authorised field responders to HPAI outbreaks in marine mammals, with a focus on biosecurity, sample collection for virus detection and carcass disposal

Since its emergence in 1996, high pathogenicity avian influenza (HPAI) caused by the H5N1 subtype, has evolved into a global panzootic, impacting Africa, Asia Pacific, the Americas, Europe, and the Middle East. Beyond domestic poultry and captive birds, it now threatens wild and domestic mammals, as well as humans. Since 2021, the HPAI H5N1 clade 2.3.4.4b strain has caused significant mortality in wild birds around the world and marine mammals in South America. Though these outbreaks have been linked to few human infections of mild to severe symptoms, all H5N1 strains (and some other subtypes) should be considered to pose zoonotic risks. Thus, this virus poses a risk to animal health, public health, and biodiversity.

Thus, early detection, immediate notification, and timely response, along with relevant biosecurity measures, are fundamental in devising containment and prevention strategies to protect animals, humans, and biodiversity.

To provide important guidance for such strategies, the current recommendations were developed. These recommendations stem from recent HPAI outbreaks in the marine mammals of South America, with potential global applicability that accounts for local conditions and differential epidemiological situations.