California health authorities are investigating a second case of human plague — the cause of the Black Death in Europe which killed 75 to 200 million people from 1346 to 1353.
The authorities in California hastened to add, however, that the risk to human health of the disease is low.
Authorities noted that both individuals who got the disease visited the Yosemite National Park.
The disease is referenced in the Old Testament, being one of the 10 biblical plagues or calamities that hit Egypt in the days of Moses. According to the Book of Exodus, God inflicted the plagues upon Egypt to persuade the Pharaoh to release the ill-treated Israelites from slavery.
Director and State Health Officer Dr. Karen Smith of the California Department of Public Health said the agency has been notified of a "presumptive positive case of plague" contracted by a visitor to California from Georgia.
Confirmatory test is being conducted by the Centers for Disease Control and Prevention (CDC).
Before becoming ill, the patient visited the Yosemite National Park, the Sierra National Forest and surrounding areas in California in early August.
The department said plague is an infectious bacterial disease that is carried by squirrels, chipmunks and other wild rodents and their fleas.
"When an infected rodent becomes sick and dies, its fleas can carry the infection to other warm-blooded animals including humans," the department said.
It said the camp grounds were closed and treated, and park visitors were notified of camp treatments and possible plague risks.
Flea treatment successfully reduced the risk of plague transmission at Crane Flat Campground and Tuolumne Meadows Campground in the National Park, the department said.
Besides the cases in California, two people died of plague this year in Colorado, according to CNN.
The Yosemite National Park shut down the Tuolumne Meadows Campground after two dead squirrels were found to have plague.
It will be closed from Monday to Friday. Yosemite has about 4 million visitors each year.
The Tuolumne site will be treated with deltamethrin, a chemical that kills fleas that spread the plague, the park said.
A child contracted the plague after visiting Crane Flat last month. The victim is recovering.
The California health department said the last reported cases of the human plague in California were in 2005 and 2006 in Mono, Los Angeles and Kern counties.
A total of 42 human cases of the plague have been confirmed in California since 1970.
