A “mortality” of more than a dozen ducklings in the reflecting pool was discovered a few weeks ago, Park Service spokesman Mike Litterst said Wednesday.
When the animals underwent autopsies, two were found to be infected with bird flu. He said it was not yet clear what killed the others.
The virus is rarely transmitted to humans. “To date, there has been only one documented human case of HPAI currently circulating in the United States,” the Park Service said in a statement.
“We don’t envision another covid-like situation,” Litterst said. “But because humans can unintentionally facilitate transfer between groups of birds, we just want to spread the word.”
So far, 39 million birds have been affected in flocks in 36 states, including 1.7 million in Maryland, 4 million in Pennsylvania and 1.4 million in Delaware, according to the US Department of Agriculture . Only 90 were affected in Virginia.
The current virus is thought to pose a low risk to the general public, according to the Centers for Disease Control and Prevention, although “some people may have occupational or recreational exposures to birds that put them at higher risk of infection.” .
But people should avoid handling live or dead birds or coming into contact with their droppings because the virus can be easily carried onto shoes, the Park Service said.
Visitors to the area should watch out for “waterfowl droppings” and pets should be kept away from live or dead birds. People should report sick or dead birds to Park Service staff.
The virus is highly contagious in some wild birds and can be fatal to bald eagles and vultures, the Park Service said.
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Mallards are less likely than many other waterfowl species to show signs of illness and can be infected without appearing sick. The term “highly pathogenic” refers to significant illness and mortality in poultry and other domestic birds that results from infection with this virus, the Park Service said.
Elsewhere in the region, 80 black vultures from Harford County, Maryland, were recently found dead from the virus near wildlife areas along the Susquehanna River, officials said. Vultures can be infected by scavenging infected dead birds.
They were part of around 950 cases in wild birds, including at least 54 bald eagles.
Agricultural authorities in Maryland and Delaware said they had reports of chickens on farms infected with bird flu since February. The vultures have been found in recent weeks.
“The numbers are just staggering in terms of poultry,” Virginia state veterinarian Charlie Broaddus said last month.
One of the biggest factors in the spread of bird flu this year, he said, is that it is carried by wild ducks and geese which are infected but “are generally not affected”.
“They are carriers,” Broaddus said, “but the genetic sequence has the potential to make domesticated birds much, much sicker.”
Broaddus said farms that have hens producing eggs that “end up in the supermarket” tend to be large-scale operations, where the flu can spread quickly.
Sometimes, he said, chickens on farms become infected when a farmer or worker “accidentally tracks down goose droppings near a pond” and then brings them into the chicken farm.
“It only takes one to get infected before passing it on to others,” Broaddus said.
Many wild birds don’t always show signs of the virus, but it can easily be transmitted between birds through their droppings or through respiratory secretions, experts said.
Agricultural officials at the Delaware-Maryland HPAI Joint Information Center expressed particular concern on vultures because they are scavengers, and “if they eat a bird infected with avian flu, whether it’s a migratory bird like a Canada goose, other waterfowl or another vulture, they ingest the virus and can then get sick and die.”
“We want to make sure [that people] are taking steps to stop the spread of the virus so they don’t inadvertently carry it to other areas with high populations of wild birds,” said Stacey Hofmann, spokesperson for the Joint Information Center.
Agricultural experts at the Joint Information Center advised the public to “help limit the spread of the disease by not moving bird droppings via their shoes to other wild bird habitats”. People should also change shoes and clean dirty shoes after visiting a wilderness or natural area.
According to a statement from the information center, experts say spraying shoe soles with a common household cleaner such as Lysol or a spray of diluted bleach will kill the bird flu virus. For those with pet birds or poultry at home, authorities recommend “washing hands, changing clothes and cleaning shoes after visiting areas frequented by wild birds.”
Dana Hedgpeth and Vanessa Sanchez contributed to this report.