A national park in California has been evacuated and partially closed after a squirrel was found to be carrying the plague.
The disease - known as the black death or bubonic plague - is transmitted by fleas and killed around 25 million people in Europe in the 14th century.
Health officials in the US say the state's recorded 4 cases since 1984, and all of them have been of the non-fatal variety.
A health advisory issued by the County of Los Angeles Public Health department said plague has been known to reside in the ground squirrels population in the San Gabriel Mountains.
Previous routine surveillance had identified one plague-positive ground squirrel in 2010, one in 2007, two in 1996 and one in 1995.
The diseased animal - a ground squirrel - was trapped in the Angeles National Forest during routine surveillance by the US Forestry Service.
The plague is treatable with antibiotics, but if left untreated, it's fatal. Symptoms include the rapid onset of chills and fever.
Health Alert: HEALTH ADVISORY: Closures Posted for Broken Blade, Twisted Arrow, and Pima Loops of the Table Mo... http://t.co/mocbxWn6AU
— LA Public Health (@lapublichealth) July 25, 2013
Campers at the affected sites - Broken Blade, Twisted Arrow, and Pima Loops - have been informed.
LA County Public Health office has posted a full statement on the evacuation and closure.
Officials say further testing of the rodents will be carried out and squirrel burrows in the area will be dusted for fleas before the area is re-opened to the public.
ABC 7 TV station in Los Angeles has this report:
