can eagles get bird flu

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.

Similar content being viewed by others

can eagles get bird flu

Liana Y. Zanette, Emma C. Hobbs, … Michael Clinchy

can eagles get bird flu

Cedric C. S. Tan, Lucy van Dorp & Francois Balloux

can eagles get bird flu

William M. de Souza & Scott C. Weaver

A symbol of successful conservation, the bald eagle (Haliaeetus leucocephalus) is an important species for both ecology and culture. The bald eagle’s breeding range includes aquatic habitats from South Carolina to Florida, the Chesapeake Bay region and north to Maine, the Great Lakes region, the Pacific Northwest, and parts of the Rocky Mountains and Gulf Coast. These areas are found throughout most of Canada and parts of the United States. Nonetheless, despite a significant rise in the number of successful bald eagle nesting pairs, individuals, and geographic range in the contiguous 48 U.S. states, concerns about species conservation still exist. S. states since the Endangered Species Act’s 1995 downlisting of the species from Endangered to Threatened1.

Exposure to environmental contaminants is one of the many ongoing human-caused threats to the bald eagle’s continued recovery. g. trauma from vehicle, wind turbine, or powerline strikes, and direct persecution1,4, as well as lead and anticoagulant rodenticides)2,3. DDT (dichloro-diphenyl-trichloroethane) metabolites in pesticides were one of the historical threats; starting in the 1950s, they significantly decreased reproductive success and nearly drove them extinct in the contiguous U.S. S. 1,5. Even though the majority of today’s threats are widespread and frequently reported, many can be lessened by legislation enforcement, conservation management, and public education campaigns. In the face of stochastic epidemiological threats, such as emerging unpredictable, uncontrollable, or inevitable infectious disease outbreaks, the efficacy of such loss-reduction strategies may decline.

In December 2021, Gs/GD H5N1 IAV (henceforth, HP IAV) was introduced to eastern North America from Europe. Over the past two decades, outbreaks of highly pathogenic (HP) A/goose/Guangdong/1/1996 lineage (Gs/GD) H5 influenza A virus (IAV) in Europe, Asia, and Africa have grown in frequency and severity in a variety of wild bird species6,7. The virus was first found in several wild bird species in Newfoundland and Labrador, Canada, in North America. Shortly after, migratory waterfowl in southern breeding grounds of the United States were also found to have the virus. To date, detections continue throughout much of North America9,10,11. There are now records of HP IAV-related deaths in a variety of wild bird species. Waterfowl, shorebirds, raptors, and scavenger birds have been the taxa most frequently infected10,11,12,13, and 14.

Since January 2022, 136 bald eagles gathered from 24 U.S. locations have shown evidence of HP IAV-related mortality. S. states, many of which are located along the southern Atlantic coast (as of June 10, 2022) 1)10. When these eagles were still alive, some of them showed signs of distress, such as head shaking, ataxia, paralysis, incapacity to fly, and/or lethargy (Supplementary videos 1 and 2). Similar to recent HP IAV H5N8 and H5N1 outbreaks in Europe, pathology was frequently severe and included brain inflammation and multi-organ necrosis13,14,15.

Regional highly pathogenic influenza. A virus in wild birds in the southeastern United States in the spring of 2022 counties where the H5 influenza A virus (IAV) (A/goose/Guangdong/1/1996 lineage HP clade 2) is present in North Carolina, South Carolina, Georgia, and Florida 3. 4. In spring 2022, 4b H5N1) was found in wild birds, according to the U S. Department of Agriculture (USDA; https://www. aphis. usda. website accessed July 22, 2022; additional detections by the Southeastern Cooperative Wildlife Disease Study, University of Georgia; gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/avian-influenza/hpai-2022/2022-hpai-wild-birds Investigations into wild bird mortality or USDA surveillance of waterfowl harvested by hunters yielded the findings. The map displays the counties where H5 IAV mortality in bald eagles has been detected (red), according to SCWDS and reports on the USDA website from January 1 to May 15, 2022; H5 IAV mortality in dead or hunter-harvested waterfowl has been detected (hash lines), according to reports on the USDA website from January 1 to April 1, 2022; and H5 IAV mortality in wild bird species other than bald eagles or waterfowl has been detected (yellow border) according to SCWDS and published on the USDA website between January 1 and May 15, 2022. Duck silhouettes, as detected by SCWDS and reported on the USDA website13, pinpoint areas where confirmed H5 IAV waterfowl mortality coincides with peak bald eagle nesting activity from January 1 through April 1, 2022.

Early phases of the outbreak in Florida, Georgia, and South Carolina temporally coincided with bald eagle nesting season. Large and productive breeding eagle populations can be found in this area, which directly supports the long-term survival of the species within the Atlantic Flyway16,17,18. Breeding pairs create their nesting grounds near bodies of water that are home to premium prey like fish or waterfowl1,19,20. These environments are frequently inhabited by waterfowl, which serve as the main source of IAV6. Before they were discovered dead close to active nests in at least four nesting territories, adult and juvenile eagles showed strange behaviors that were frequently misinterpreted as neurological symptoms. Other eagles clearly fell from nests. These mortalities were confirmed as HP IAV infections. It was later discovered that one or both of the parents at two of these nest sites had died from HP IAV after going missing (Fig. 2a,b,c,d). These results have raised concerns about the outbreak’s possible longer-term and more widespread effects on population health.

s showing severe illness and death from infection with the H5 influenza A virus in bald eagles (Haliaeetus leucocephalus) (a) On February 17, 2022, in Brevard County, Florida, a pair of bald eagles (nest BE106) were observed being attentive to their young, which appeared to be healthy (photo by Bob Glover). (b) A bald eagle nestling from the same nest (BE106), photographed by Bob Glover on February 18, 2022, after it was discovered dead beneath the nest and determined to have died from an H5 IAV infection. (c) An adult female bird found dead under the nest on February 24, 2022, from an H5 IAV infection, is being collected by a Florida Fish and Wildlife Conservation Commission law enforcement officer (photo by Bob Glover). (d) An adult Davidson County, North Carolina bald eagle with an H5 IAV infection who showed up with severe neurologic symptoms at a wildlife rehabilitation center (e g. , extreme tiredness, convulsions, and partial paralysis); the eagle received oxygen, subcutaneous fluids, antibiotics, and diazepam (Valium®); however, it passed away the next morning (picture by Jackie Schaible).

Vigilance in the Everglades

Birds can perish from natural causes like disease, starvation, and predators, or they can die from accidents like hitting cars. Thus, occasionally having to remove and dispose of bird carcasses may be essential to a park biologist’s duties. Gathering and getting rid of a single dead bird is not too difficult. However, handling a lot of carcasses makes the task much more challenging. This is particularly true if the suspected cause of death is a zoonotic illness like HPAI. Such was the case for biologists at Everglades National Park.

Situated in south Florida, the park is the nation’s largest subtropical wilderness. It is famous for its unique plants and animals. Among the more than 360 different species of birds observed in the park are sizable populations of both resident and migratory turkey vultures and black vultures. On March 30, 2022, a park law enforcement ranger discovered at least 20 dead vultures at the park’s eastern entry point, the Chekika day use area, while on routine patrol. Park biologists Lori Oberhofer and Raul Urgelles were aware that vultures in more northern parts of Florida had previously been reported to have HPAI. So they prepared to visit the site the next morning.

Many dead black vultures were discovered by law enforcement ranger Jeffrey Gonzalez in the Everglades National Park’s Chekika parking lot. Testing confirmed they died from avian influenza.

credit: NPS / Jeffrey Gonzalez

Oberhafer and Urgelles arrived wearing full protective gear to prevent infection, even in the sweltering 90 degree heat. This included nitrile gloves, plastic shoe covers, eye goggles, Tyvek suits, and N95 masks. They observed numerous dead black vultures strewn throughout the grassy parking lot and the surrounding flora. Some vultures perched in the nearby trees, while others feasted on the dead birds that lay on the ground. Two clearly sick birds slowly moved away and vanished into the dense undergrowth beneath the trees.

The scientists gathered 65 fresh vulture carcasses for disposal and one fresh carcass for laboratory analysis. Employees at the landfill in Miami-Dade County were prepared and waiting to receive the carcasses at an animal burial site. Workers at the landfill quickly covered the bagged birds with dirt to stop other scavengers from consuming them and potentially contracting an infection. The fresh vulture carcass tested positive for HPAI in the laboratory.

“Despite removing or burying close to 200 carcasses over three weeks, the mortalities continued.”

After Chekika, park biologists realized it would be impossible to locate and remove all carcasses or sick birds across an area as large as Everglades. Dr. Mark Cunningham is the diagnostic veterinarian manager at the Florida Fish and Wildlife Conservation Commission. He participated in a vulture roost study at Hontoon Island State Park north of the Everglades. “Despite removing or burying close to 200 carcasses over three weeks, the mortalities continued,” he said. “Some of the pitfalls we ran into were the difficulty in finding every carcass—there are always some that we miss—and they fact that sick birds were dying continuously.”

Dr. Cunningham stated that someone would need to be present at the roost all day in order to remove carcasses. He continued, “At this point, I don’t think carcass removal will be effective unless all carcasses are completely removed daily, multiple times per day, for several weeks.” “Ill vultures can roost at different locations, resulting in adjacent outbreaks.” “.

Park biologists at Everglades are concerned this disease might affect other bird species in the park, but they know protecting birds from HPAI in such a huge park is not feasible. Wading bird nesting colonies of egrets, herons, wood storks, and roseate spoonbills are magnets for vultures, who prey on both live and dead nestlings. Infected vultures likely congregate among wading bird colonies. For now, the park remains vigilant for new outbreaks.

FAQ

Do bald eagles get sick?

Parasites are another danger to eagles in the wild and can lead to death as well as sickness. Eagles face many diseases in the wild, a few of the more well-known ones being West Nile Virus, Highly Pathogenic Avian Flu and pox viruses, the latter causing blindness and potential beak and talon deformities.

Which birds carry bird flu?

Which birds are most likely to be infected with avian (bird) influenza (flu) A viruses? Wild birds that carry bird flu viruses include waterbirds, like ducks, geese and swans, and shorebirds, like storks. Bird flu viruses can easily spread from wild birds to poultry, like chickens and turkeys.

What is the disease that the bald eagle has?

Avian Vacuolar Myelinopathy (AVM) This is a neurologic disease that affects water birds as well as raptors, including the bald eagle. It is believed to be caused by a toxin produced by a cyanobacterium (a blue-green alga). This bacter–ium grows well on aquatic plants such as Hydrilla verticillata.

Is bird flu fatal to all birds?

Avian influenza, or “bird flu,” is a respiratory disease of birds caused by influenza A viruses. Wild birds, such as ducks, gulls, and shorebirds, can carry and spread these viruses but may show no signs of illness. However, avian influenza can kill domestic poultry (such as chickens, turkeys, ducks, and geese).