A highly contagious strain of bird flu that has ravaged wild bird populations globally is killing an unprecedented number of nesting bald eagles in coastal Georgia and Florida, according to a new study from UGA scientists and other researchers.
The researchers say more monitoring is needed across North America to determine whether similar die-offs are occurring across the continent. But if the trend documented in the Southeast is confirmed elsewhere, it could threaten a decades-long conservation effort that successfully brought bald eagles back from the brink of extinction.
“Even just one year of losses of productivity like we’ve documented regionally is very concerning and could have effects for decades to come if representative of broader regions,” said Nicole Nemeth, the study’s lead author and an associate professor at UGA’s College of Veterinary Medicine, in a release about the findings. “We have already lost unprecedented numbers of wild birds due to this virus in the U.S. and it appears here to stay.”
The findings were published earlier this year in the peer-reviewed journal Nature Scientific Reports.
For the first time last year, the state’s Department of Natural Resources (DNR) announced that the virus had been detected in three dead bald eagles in Georgia.
The Nature study found that fewer than half of monitored bald eagle nests in six coastal Georgia counties successfully fledged an eaglet in 2022, a rate that’s 30% less than normal. Similar drops in fledging success rates were observed in four Florida counties.
The virus that is killing bald eagles is the H5N1 strain of Highly Pathogenic Avian Influenza (HPAI). While H5N1 has been circulating globally for years, cases in the U.S. among wildfowl, songbirds and commercial chicken and turkey flocks began skyrocketing early last year. The price of chicken eggs has roughly doubled over that time, in large part due to the virus.
More than 58 million wild birds, commercial poultry and birds in backyard flocks have been infected or culled to stop the virus from spreading in the U.S. to date, according to data from the Centers for Disease Control and Prevention (CDC).
Georgia’s commercial poultry industry, the country’s top producer of broiler chickens, has not reported any cases so far connected to the current outbreak, according to the Georgia Department of Agriculture.
Still, a spokesperson for the department called the outbreak “concerning,” adding that the department is “continuously monitoring the situation to ensure the highest standards of poultry health.”
The state’s poultry industry continues to test regularly for the virus in conjunction with the Georgia Poultry Laboratory Network (GPLN), the spokesperson said. The GPLN administers roughly 1,100 tests per day and every commercial broiler flock in the state is tested prior to being processed. Commercial breeding and egg laying flocks are also tested at 2–3 month intervals, the agency said.
The virus has also shown the ability to infect wild mammals. Red foxes, coyotes, racoons, seals, opossums and bears have all tested positive for the H5N1 in North America, but no mammals have tested positive so far in Georgia.
For now, the CDC says H5N1 poses little risk to humans and infections, while rare, have a high fatality rate. One human case was reported last year in Colorado in a patient involved in culling birds. The patient survived. Hundreds of human infections have occurred in other countries, typically after long periods of unprotected contact with infected birds, the CDC says.
Since 1997, more than 880 people around the world have been infected with H5N1, according to the CDC, with a case fatality rate of about 50 percent. From 1997-2003, 20 cases and 7 deaths were reported in Hong Kong, and more than 860 cases have been reported in 21 countries since November 2003.
Though human cases remain extremely rare, H5N1′s widespread circulation among birds and now mammals creates more opportunities for the virus to jump to humans, said Rebecca Poulsen, a scientist at UGA’s Southeastern Cooperative Wildlife Disease Study and a co-author of the study.
“I think that the longer this virus is out in the landscape, it just gives it more and more chances to change and adapt,” Poulsen said. “There hasn’t been much evidence yet to support that these viruses are moving from mammal to mammal to mammal, but that’s something we as a collective research community are really trying to keep our finger on the pulse of.”
Symptoms of H5N1 in birds include lethargy, tremors and seizures. The Georgia Department of Natural Resources (DNR) says the public should report birds to the agency that are dead or suspected to be sick. The agency warns that the animals should not be handled.
Hunters should also exercise caution when handling raw meat, and DNR says all game birds and poultry should be cooked thoroughly. While dogs are not at high risk of infection, the agency said, dogs should be kept away from obviously sick or deceased birds and should not be fed raw game meat.
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