The virus that causes bird flu, which has infected millions of wild and domesticated animals across dozens of states, has been detected in mallard ducklings at the Lincoln Memorial Reflecting Pool in Washington, the National Park Service said.
It's the first case that has been found in Washington, D.C., though surrounding states have reported cases, including Maryland, Delaware and Virginia.
The National Park Service is urging tourists and visitors not to handle live or dead birds at the memorial.
"Pets should be kept leashed and not allowed to interact with live or dead birds or other wildlife," the park service said. "Visitors can assist by reporting observations of sick and dead birds, or other ill wildlife, to park staff."
Infected birds shed the virus primarily through their saliva and feces, though human cases are exceedingly rare.
The CDC has counted bird flu cases in more than 40 million domesticated birds and about 1,400 wild birds, but there has only been one case in humans.
A man who works with infected poultry in Colorado tested positive via a nasal swab in late April and recovered after taking the antiviral drug oseltamivir.
Since 2003, there have been more than 860 human infections across 19 countries, about half of which have resulted in death, according to the CDC and World Health Organization.