Bald eagle mortality and nest failure due to clade 2.3.4.4 highly pathogenic H5N1 influenza a virus

Abstract

The bald eagle (Haliaeetus leucocephalus) is a culturally and ecologically vital species in North America that embodies conservation success but continues to face threats that include emerging pathogens. The introduction of A/goose/Guangdong/1/1996 lineage highly pathogenic (HP) clade 2.3.4.4b H5N1 influenza A virus (IAV) in North America in late 2021 resulted in high rates of mortality among bald eagles. Here we show an alarming rate of bald eagle nest failure and mortality attributed to HP IAV. We documented fatal, systemic HP IAV infection in breeding adult and nestling bald eagles along the southeastern U.S. coast. Concurrently, annual bald eagle nest surveys in Georgia and Florida revealed a precipitous drop in success in coastal counties compared with previous years, portending negative impacts on population recruitment. As an apex predator and efficient scavenger, it is likely that bald eagles become infected through consumption of infected waterfowl. These results and similar reports of raptor mortality in Europe, Asia, and Africa, indicate a clear threat to raptor health. The possible long-term persistence of HP H5N1 IAV in North America poses an impending threat to bald eagle populations not only related to direct mortality but also decreased recruitment and warrants continued efforts to understand these potential impacts.

Spatio-temporal dynamics and drivers of Highly Pathogenic Avian Influenza H5N1 in Chile

“…This epidemic pattern is similar to the one observed in North America where the virus disseminated fast throughout continental United States and all provinces of Canada, affecting ~28,000 wild birds among sick and mortality estimates (Harvey et al 2023), or in Peru, where more than 120,000 wild birds and 3,000 marine mammals have died since October 2022 (Gamarra-Toledo et al 2023). In addition, in the United States H5N1 has been associated with high mortality rates and breeding failure in the bald eagle (Haliaeetus leucocephaus; Nemeth et al 2023) and unusual mortalities in the highly threatened California condor (Gymnogyps californianus) have been recently reported. Likewise, the arrival of H5N1 to Tierra del Fuego in the extreme south of Chile, is now an imminent threat to Antarctic fauna.…”

“…The current panzootic of Highly Pathogenic Avian Influenza A subtype H5N1 clade 2.3.4.4b (hereafter H5N1) is causing large mortalities of wild populations of birds and mammals worldwide (Gamarra-Toledo et al 2023a, Leguia et al 2023, Nemeth et al 2023). In addition, >200 million domestic poultry have died or been culled as a control management (World Organization of Animal Health 2023), threatening food security of low-and middle-income countries.…”

Breeding Bald Eagle (Haliaeetus leucocephalus) Population and Demographic Trends in Florida, 1972–2017

“…As with other long-lived avian species, survival of juvenile and adult eagles is believed to play a greater role in long-term population stability than breeding productivity alone (Grier 1982). Bald Eagles in Florida face threats, including anticoagulant rodenticides (van Deventer et al 2017, Niedringhaus et al 2021), avian vacuolar myelinopathy (Breinlinger et al 2021), highly pathogenic avian influenza (Wille and Barr 2022, Nemeth et al 2023), and exposure to heavy metals (van Deventer et al 2017, Hanley et al 2022, Slabe et al 2022). Future assessments seeking to further quantify the viability of eagles in Florida should explore the role of adult and post-fledgling survival (e.g., Hanley et al 2019), the implications of climate change on breeding territory suitability, and the influence of nonbreeding individuals (e.g., Turrin and Watts 2014) at various spatial scales.…”

Lesions and viral antigen distribution in bald eagles, red-tailed hawks, and great horned owls naturally infected with H5N1 clade 2.3.4.4b highly pathogenic avian influenza virus

“…2,11,36 Disease and death in raptors, specifically, have been reported previously due to H5 2.3.4.4 clade viruses and prior clades of the A/goose/Guangdong/1996-lineage (gs/GD) H5 HPAIV. 8,9,12,18,26,27,29,39 Experimental infections with gs/GD viruses have resulted in neurologic disease and death in various raptor species. 5,14,24,34 Our postmortem study describes the lesions and viral antigen distribution in 3 species of raptors, including bald eagles ( Haliaeetus leucocephalus ), red-tailed hawks ( Buteo jamaicensis ), and great horned owls ( Bubo virginianus ) naturally infected with H5N1 clade 2.3.4.4b HPAIV during the 2022 outbreak.…”