Squirrels retrieved from campgrounds in the San Jacinto Mountains tested positive for bubonic plague bacteria, prompting Riverside County health officials on Tuesday to warn campers and hikers to take precautions.
According to Department of Environmental Health spokeswoman Dottie Merki, several squirrels netted earlier this month at the Dark Canyon and Marion Mountain campgrounds were verified as plague carriers after blood screenings were conducted at a state lab. The tests took place on June 8 and June 13, Merki said.
Dark Canyon is near Mountain Center, just east of state Route 243. Marion Mountain is just south of there. Both are in the San Bernardino National Forest.
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Rodents are trapped in the mountain locations seasonally to ascertain whether they're carrying diseases, according to Merki. She said it's the first time since October 2012 that a squirrel has tested positive for plague exposure. Fleas who feed on infected rats and other rodents carry plague bacteria and can transfer it to humans, causing a bacterial infection in some cases.
People can also be infected by handling an animal who died of plague, according to the National Institutes of Health.
There are different varieties of plague -- bubonic, pneumonic and septicemic. Bubonic is the deadliest, killing about half of all victims if left untreated, according to the government.
Merki said plague is endemic to a number of mountain locations throughout Southern California, including the San Jacinto wilderness.
"All campgrounds are continuously posted to remind campers that plague has been found in the area in the past," she said. "Follow-up rodent surveillance and an environmental assessment of the two campgrounds will be conducted this week. Risk to the public is currently considered to be low, and campgrounds will remain open during the follow-up investigations."
Merki said a few simple precautions can minimize the possibility of being exposed to plague-infected fleas and rodents:
- Don't bivouac near rodent burrows;
- Don't handle dead wild animals, or play with live ones;
- Keep pets on a leash and treat them for fleas;
- Notify campground personnel of dead rodents for disposal. Plague symptoms include sudden fever, chills and tender or swollen lymph nodes.