The earliest known US virus-related fatalities have been confirmed in California as more deaths are investigated

The Santa Clara County Medical Examiner-Coroner performed autopsies on two individuals who died in their residences in February and sent samples to the US Centers for Disease Control and Prevention, the county said in a news release.

A third death in early March was also confirmed to be virus-related, the release said.

At the time of the deaths, the news release says, testing for the virus was very limited and only available through the CDC.

“Testing criteria set by the CDC at the time restricted testing to only individuals with a known travel history and who sought medical care for specific symptoms,” the release says.

The results, which came back from the CDC on Tuesday, confirmed both tissue samples tested positive for the virus.

Further details on the victims were not provided.

The release states that as more deaths in the county are investigated, it’s likely there will be more that are tied to the virus.