Los Angeles County public health and U.S. Forest Service officials have closed the Los Alamos Campground in the Angeles National Forest after a California ground squirrel captured two weeks ago tested positive for plague.
The camp, between Gorman and Pyramid Lake, was closed Saturday afternoon and will remain closed for at least 10 days, said Jonathan Fielding, the county's public health director. Squirrel burrows in the area will be dusted for fleas, and further testing will be conducted before the campground is reopened.
"We're fortunate to have caught this," Fielding said. "This case now is about prevention."
Plague is a bacterial disease in wild rodents that can be transmitted to humans through the bite of infected fleas. The symptoms of one deadly form of the disease, bubonic plague, include enlargement of the lymph glands near the flea bite and rapid onset of fever and chills. If left untreated, the disease can infect the blood, or, on rare occasions, the lungs, causing pneumonic plague.
"It is important for the public to know that there have only been four cases of human plague in Los Angeles County since 1984, none of which are fatal," Fielding said.
Ground squirrels have long been a problem for some cities. For years, Santa Monica faced an overpopulation of the squirrels at Palisades Park. The city was cited several times by the county for rodent overpopulation and tried various suppression methods, including poison gas. Berkeley also faced a similar problem.
Plague is endemic among ground squirrels in the San Gabriel Mountains. In 2007, routine surveillance identified one plague-positive squirrel. In 1996, two squirrels taken from the Stonyvale picnic area near La Cañada Flintridge tested positive for the disease, and one squirrel from an adjacent campground in Vogel Flats tested positive in 1995. In April 2009, the disease was found in ground squirrels at a popular camping site on Palomar Mountain in northern San Diego County.
Visitors to Los Alamos Campground are advised to avoid squirrels and chipmunks and stay clear of animal burrows, which can be hot spots for fleas. "Protection with an insect repellant containing DEET is also recommended for persons visiting the Angeles National Forest and engaging in outside recreational activities in other areas of L.A. County," Fielding said.