Authorities in the U.S. state of Georgia have confirmed that the avian influenza virus is present in the state, with three known cases of infection among the iconic bald eagle population.
The University of Georgia’s Southeastern Cooperative Wildlife Diseases Study first reported on cases of the avian flu virus inside state borders earlier in March: three dead eagles were found carrying the virus in Chatham, Glynn, and Liberty counties at that time. Since then, a total of 11 cases of wild bird influenza have been confirmed in the state, and more than 660 throughout the United States.
Although the virus is of low risk to humans and no human cases of avian flu have been reported in the U.S. to date, the spread of the virus can have a severe impact on the health of commercial poultry. So far, no cases of infection with this virus have been reported in commercial poultry in Georgia.
Bird flu
“We don’t know what the future holds, but worst case scenario: The virus becomes established in our wild bird populations,” said David Stallknecht, director of the Southeastern Cooperative Wildlife Disease Study. “If it is maintained in wild birds, it will continue to threaten wild bird and commercial poultry health. With bird migration it may even spread to Central America and South America.”
Confirmation of the virus’ presence was given this week by the United States Department of Agriculture (USDA) National Veterinary Services Laboratories in Iowa. The laboratory worked with samples retrieved during the discovery of the three eagle bodies back in March.
The strain identified by the lab is known as HPAI — highly-pathogenic avian influenza — or ‘high-path’ for short. It has been identified in over 50 countries on several continents in animals ranging from wild waterfowl to commercial poultry. It has a relatively high ability to infect other animals as well and has occasionally been recorded to infect humans and other mammals.
While seeing an avian-specific virus infect birds isn’t particularly surprising, the scale of the outbreak is quite troubling, Stallknecht says. Birds of prey are widely affected by the outbreak, with many raptors in several U.S. states being infected.
“There is an outbreak going on in Florida right now involving hundreds of black vultures. Mortality due to HPAI has been documented in numerous species of geese, ducks, gulls, and pelicans. However, not all infected birds die,” he explains.
Some populations of ducks and other waterfowl are known to show no symptoms when infected with HPAI, likely as a result of acquiring immunity from exposure to less-infectious flu viruses (‘low-path’ strains) which are quite frequent in these birds. Raptors that hunt waterfowl, such as eagles, do not typically become exposed to these low-path strains, meaning they may lack the same evolved immunity to keep them safe from HPAI.
HPAI has heavily impacted this nesting season for coastal bald eagles in Georgia, authorities report based on a survey of bald eagle nests in the state.
“On the coast, the numbers are pretty sobering,” said Bob Sargent, one of the program managers for the Georgia Department of Natural Resources. “What we found is the nest success rate for those coastal birds was over 30% lower than it normally is. You can’t say definitively that high-path caused all those nest failures, but clearly it’s played a substantial role in that remarkably substantial drop.”
Success for a bald eagle nest is defined as at least of eaglet fledging — i.e. maturing enough to be able to fly on their own. These birds typically lay two eggs at a time, and roughly 7 to 8 in 10 nests succeed every season. Bald eagle populations are still recovering throughout the U.S. from historic lows. Georgia didn’t have a single reported successful nest between 1971 and 1980; today, it has over 100 active nests.
“This virus is cause for concern, but it’s not cause for panic,” Sargent said. “The eagle population has come a long way since the 1970s. The eagle population is not in crisis.”
Viral outbreaks in the wild are tragic events, but they are natural ones. Authorities are hoping that wild populations in the affected states don’t suffer greatly at the hands of the virus. Still, they’re trying to do everything in their power to help; if you happen to see a sick-looking eagle or a dead one with no obvious injuries, contact the Department of Natural Resources to retrieve the body and dispose of it safely.
This particular disease kills a lot of birds really quickly if they get it. We appreciate the public being our eyes and ears out there, particularly in remote areas,” said Tina Johannsen, assistant chief of game management for the Georgia Department of Natural Resources. “If you see something that seems unusual, particularly if it’s more than one dead bird in a location, don’t handle it. Call us, and we can give you advice on the best thing to do for it.”
