Multidisciplinary Tracking of Highly Pathogenic Avian Influenza A(H5N1) Outbreak in Griffon Vultures, Southern Europe, 2022

Since 2021, highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b virus has affected wild bird populations globally. Griffon vultures (Gyps fulvus), a species hitherto considered unexposed, experienced an HPAI H5N1 outbreak in 2022 in southern Europe, leading to moderate mortality and reduced breeding success. The integration of virological, serologic, phylogenetic, and ecologic data revealed a short yet intense viral circulation and a probable common source of infection. The dissemination across Spain and France was likely caused by frequent interpopulation movements of birds. This integrated overview of the 2022 HPAI outbreak in vultures provides novel insights into the role of large-scale movements of wild birds in the spread of such disease. Understanding the epidemiologic dynamics of HPAI H5N1 in these scavenger species is crucial because the birds play vital roles in ecosystem functioning. Their susceptibility to this virus highlights potential broader ecologic effects of the ongoing outbreaks.