El Dorado County health officials have been notified by the California Department of Public Health (CDPH) that a flea from a Yellow pine chipmunk in the Tahoe area has tested positive for plague. The flea was sampled from one of three rodents trapped in the Fallen Leaf Campground area during routine plague surveillance May 18, 2016. State test results confirming plague were received on June 2.

Oriental rat flea, Xenopsylla cheopis/CDC

Warning signs are posted in the affected area and individuals are advised to report dead or sick rodents. All campers checking in are provided with educational materials about plague. Health officials are not aware of any human contact with infected rodents in the Fallen Leaf area.

Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County. Additional plague testing will be performed the week of June 6 in the Fallen Leaf Campground area.

Plague is an infectious bacterial disease spread by squirrels, chipmunks and other wild rodents and their fleas. People can get plague when they are bitten by an infected flea or through close contact with an infected rodent or pet. Plague can be prevented by avoiding contact with wild rodents, and by keeping pets away from rodent burrows.

Symptoms of plague usually show up within two weeks of exposure to an infected animal or flea and include fever, nausea, weakness and swollen lymph nodes. Plague can be effectively treated with antibiotics if detected early.

CDPH routinely monitors rodent populations for plague activity in California and closely coordinates with county health officials. Last year in El Dorado County, a California ground squirrel at the Tallac Historic Site tested positive for plague in September 2015. In 2014, two live rodents tested positive for plague antibodies and three tested positive in 2013. However, there were no reports of illness to people in El Dorado County. In the entire state of California, there were two human cases of plague in 2015 after exposure to infected rodents in Yosemite Valley. Both people were treated and recovered. These were the first reported human cases in the state since 2006.

Tips to prevent plague include the following:

  • Do not feed squirrels, chipmunks or other wild rodents.
  • Never touch sick, injured or dead rodents.
  • Do not camp, sleep or rest near animal burrows or areas where dead rodents are observed.
  • Look for and heed posted warning signs.
  • Wear long pants tucked into boot tops and spray insect repellent containing DEET on socks and pant cuffs to reduce exposure to fleas.
  • Leave pets home if possible; otherwise keep pets on a leash.  Do not allow pets to approach sick or dead rodents or explore rodent burrows. Protect pets with flea control products.
  • Pet cats are highly susceptible to plague and can pose a direct threat to humans. Keep cats away from rodents. Consult a veterinarian if your cat becomes sick after being in contact with rodents.
  • If you get sick after being in an area where plague is known to occur, consult a physician and tell them you may have been exposed to plague.

State and local health officials will continue to monitor plague-prone areas.