Black vulture study raises concern about year-round H5N1 spread: full analysis

A newly published Scientific Reports paper is putting black vultures in sharper focus in the H5N1 story. University of Georgia researchers reported that 84.3% of 134 dead black vultures collected from seven southeastern states in 2022 and 2023 tested positive for highly pathogenic avian influenza, reinforcing concerns that this abundant scavenger species may be supporting year-round viral circulation rather than participating only in the typical migratory-season pattern. The study was published January 23, 2026, with the version of record posted February 12. (nature.com)

The findings build on earlier signals from the field. Black vulture mortality events tied to H5N1 were documented soon after the current North American outbreak began, including confirmed cases in Maryland in May 2022 and a 2025 Journal of Wildlife Diseases report describing 2022 outbreaks in U.S. black vultures. That earlier work warned infected black vultures could become a source of exposure for other wildlife, captive wildlife, domestic poultry, and livestock. (news.maryland.gov)

In the new study, investigators found not just high positivity, but a pattern of disease consistent with oral exposure to heavy viral loads. The paper reported enlarged, mottled spleens and livers in many birds, widespread necrosis in examined tissues, and digestive tract lesions that support the idea that ingestion of infected carrion is a major route of infection. The authors concluded that conspecific scavenging may have helped maintain mortality year-round in 2022, creating what they described as an efficient, self-perpetuating transmission system in black vultures. They also noted that while spread outside seasonal migration is concerning, it may still be self-limiting at the population level. (nature.com)

University of Georgia’s public summary pushed the implications further into ecological and veterinary territory. Lead author Dr. Nicole Nemeth said the birds examined may represent “tens or hundreds of thousands” of black vultures affected more broadly, while co-author David Stallknecht said the carcasses studied are only one part of a much larger picture. UGA also highlighted a possible silver lining from prior work: some vultures appear to survive infection and develop antibodies, suggesting intense transmission does not always mean uniformly fatal outcomes. (news.uga.edu)

The broader wildlife literature supports the concern that scavenging raptors and vultures are becoming important sentinels, and possibly amplifiers, in the ongoing H5N1 panzootic. Related studies have documented survival and antibody evidence in some raptor species, while work in Europe and North America has shown severe impacts in vultures, eagles, and condors. Separately, USGS reported a 2025 vaccine trial in black vultures and California condors after HPAI outbreaks in condors, a sign that wildlife agencies are already thinking beyond surveillance alone for especially vulnerable populations. (nature.com)

Why it matters: For veterinarians, especially those in poultry, mixed animal, wildlife, shelter, public health, and rural practice, the study is a reminder that H5N1 exposure risk doesn’t stop with waterfowl. Black vultures concentrate around carcasses, dumpsters, feed areas, and farms, and they can bridge wildlife and domestic settings in ways that routine seasonal assumptions may miss. That matters for farm biosecurity, carcass disposal, wildlife deterrence, differential diagnoses in exposed animals, and counseling pet parents whose dogs may contact dead birds or scavenged remains. USDA APHIS guidance already emphasizes wild bird surveillance and wildlife management in avian influenza prevention, and these findings suggest scavenger ecology should be more central in veterinary risk conversations. (direct.aphis.usda.gov)

What to watch: The next phase is likely to center on surveillance and translation: whether APHIS and state partners report more black vulture detections, whether researchers can better quantify population impacts, and whether evidence of persistent circulation changes how veterinarians and producers manage carcass access, wildlife interfaces, and outbreak preparedness. For conservation medicine, another key question is whether lessons from black vultures will shape preventive strategies for endangered scavengers such as condors. (direct.aphis.usda.gov)