A quarter of the staff at Seattle's Life Care Centre - which has seen the bulk of coronavirus deaths in the US - have tested positive for the disease, health officials have revealed.
The centre, located in the suburb of Kirkland, has seen at least 27 deaths.
On Saturday, as the national death toll reached 57 and the number of infections passed 2,500, officials in Washington's King County, which includes Seattle, revealed the toll on staff and carers at the centre.
The King County health department said of 95 of the 180 staff at the centre who had shown symptoms, 47 had tested positive for the virus, 24 tested negative, 1 had tested inconclusively and the results for 5 people were pending.
It said, another 15 of the staff had undergone testing on Saturday.
"First responders, medical, and care staff county-wide, including those at Life Care Centre are encouraged to actively monitor themselves for symptoms per CDC guidelines," the department said.
With three more deaths in Washington state and the first reported deaths in Louisiana and Virginia, 57 Americans have now died because of coronavirus.
Two deaths in New York and two deaths in Florida were reported also on Saturday.
Globally, there are at least 155,423 confirmed coronavirus cases and more than 5,800 deaths, ABC News said.