LOS ANGELES - A second Yosemite National Park campground will be shut down for five days after a pair of dead squirrels were found to be infected with the plague, park and California public health officials said on Friday.
The closure of Tuolumne Meadows Campground comes a week after a child who camped elsewhere in Yosemite, one of America's top tourist destinations, was hospitalised with the disease.
The case marked the first time a human was known to be infected with the centuries-old scourge, which is carried by rodents and the fleas that live on them, in California since 2006.
The campground will be closed from Monday through Friday of next week based on "new evidence of plague activity in animals,"Karen Smith, director of the California Department of Public Health, said in a statement.
A Yosemite spokeswoman said the evidence was found in two dead squirrels.
The youth diagnosed with plague had camped in July at the Crane Flat Campground, 17 miles northwest of Yosemite Valley. That campground was closed and treated with insecticide. It reopened on Friday.
The child, who was visiting the park from Los Angeles County, was said to be recovering from the illness.
Smith said that despite the recent discovery of plague in Yosemite the risk to humans remained low and visitors were being advised on how to avoid transmission of the disease. "Although this is a rare disease, and the current risk to humans is low, eliminating the fleas is the best way to protect the public from the disease," Smith said.
Health officials told park visitors to avoid walking or camping near rodent burrows, to wear long pants tucked into boots and to spray insect repellent containing the chemical diethyltoluamide, or DEET, on socks and pant legs.
Early symptoms of plague include high fever, chills, nausea, weakness and swollen lymph nodes in the neck, armpit or groin, according to the health department.
The last reported cases of human plague in California occurred in 2005 and 2006 in Mono, Los Angeles and Kern counties, the health department said.
Two people have succumbed to plague this year in Colorado, according to health officials there.
In 2012, another disease carried by rodents, called hantavirus, sickened nine people, killing three of them. Most of those cases were linked to dust from mouse droppings in tent cabins at Yosemite's Curry Village.