The El Dorado County Department of Environmental Health was notified this week by the California Department of Public Health (CDPH) that two additional chipmunks in the South Lake Tahoe area have tested positive for plague. One of the chipmunks was found in the Tallac Historic Site area and one was near the U.S. Forest Service (USFS) Taylor Creek Visitor Center.

The chipmunks were tested as part of a surveillance effort initiated by health officials after learning earlier this month that another chipmunk had tested positive for plague at the U.S. Forest Service Visitor Center in the Taylor Creek area.

A total of 41 rodents (38 chipmunks and 3 squirrels) were tested as part of the most recent surveillance effort. According to Interim El Dorado County Health Officer, Dr. Robert Hartmann, the surveillance test results are not unexpected, but do warrant precautions and notification to the public. Warning signs will continue to be posted in the affected areas and surrounding campgrounds throughout the coming months. CDPH and El Dorado County Vector Control plan to conduct follow-up surveillance in the early spring. “Risk of transmission is significantly reduced during the winter months because rodents and their fleas are less active when the weather is cold,” said Dr. Hartmann.

Plague is an infectious bacterial disease that is spread by squirrels, chipmunks and other wild rodents and their fleas. People can become infected through close contact with infected animals or infected fleas. Plague can be prevented by avoiding contact with these wild rodents and their fleas, and by keeping pets away from wild rodents and their burrows.

Plague is naturally present in many parts of California, and most commonly occurs in the mountains and foothill areas. Cases of human plague in the United States are rare. Plague can be treated effectively with antibiotics if detected early. Symptoms of plague typically occur within two weeks of exposure to an infected animal or flea, and include fever, nausea, weakness and swollen lymph nodes.

Tips to prevent plague include the following:
Do not feed squirrels, chipmunks or other wild rodents. Store food and garbage in rodent-proof containers.
Never touch sick, injured or dead rodents.
Do not camp, sleep or rest near animal burrows.
Look for and heed posted warning signs.
Leave pets home if possible; otherwise keep pets confined or on a leash. Do not allow pets to approach sick or dead rodents or explore rodent burrows. Protect pets with flea control products.

Cats can pose a risk of plague transmission to humans when they have contact with infected rodents. Keep cats away from rodents. Consult a veterinarian if your cat becomes sick after having been in contact with rodents.
To report a sick or dead rodent, contact El Dorado County Vector Control at (530) 573-3197.

Additional information about plague in California can be found at the California Department of Public Health’s website – www.cdph.ca.gov/HealthInfo/discond/Pages/Plague