Parts of a national forest in the US state of California have been evacuated and closed down after a squirrel was found to be infected with the plague.
Officials in Los Angeles say visitors were ordered to leave the Angeles National Forest as a precaution after the rodent was trapped during a routine check.
They said no people in the area were believed to have been infected with the disease, known as the Black Death, which killed as many as 25 million Europeans during the Middle Ages, the BBC reports.
There have been only four cases of human plague in Los Angeles County since 1984, none of which were fatal, officials say.
Further testing of squirrels in the region will be carried out before the campgrounds are re-opened to the public.
Jonathan Fielding, director of the Los Angeles County Department of Public Health, said agriculture workers would dust squirrel burrows in order to reduce the flea population.