If you plan on visiting Lake Tahoe (a large freshwater lake in the Sierra Nevada of the U.S.) anytime in the near future, you might want to make sure you’re thoroughly covered up and wearing some sort of natural insect repellent. A flea from a yellow chipmunk in the area tested positive for plague, the U.S. Forest Service announced June 6.
The Lake Tahoe Basin Unit of the Forest Service, El Dorado County, Calif., officials and the California Department of Public Health confirmed they had discovered plague a flea taken from Fallen Leaf Campground, located about a quarter of a mile north of Fallen Leaf Lake in South Lake Tahoe.
The Forest Service reports that the flea was taken during routine plague surveillance May 18, with state results confirming it was the plague June 2.
Warning signs have since been posted in the area. 
Animals such as chipmunks, squirrels, and other wild rodents can harbor fleas that carry plague. The infectious disease is naturally present in many parts of California. Humans can become infected when they are bitten by a flea that has plague, or through close contact with an infected rodent or pet. The illness can cause fever, nausea, weakness, and swollen lymph nodes, and symptoms usually appear within 2 weeks of initial contact with an infected animal. Though it can be cured with antibiotics, plague can be deadly if left untreated.
During the Middle Ages, plague killed millions of people in Europe. The disease is quite rare now, especially in the U.S.
An average of 7 human plague cases are reported nationwide each year, according to the CDC. Most of those cases occur in rural areas in the west, including northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon, and far western Nevada. In California, drought conditions were blamed for new plague cases.
Last year, the CDC urged doctors to consider a possible diagnosis of plague in people presenting with fever, abdominal pain, nausea, and vomiting, especially if that individual had recently visited the Western United States or are residents of the region.
Between April and August 2015, 11 people were diagnosed with plague – an unusually high number of cases.
7 Precautions to Take to Protect Yourself
Health officials are urging people to take the follow precautions against plague:
- 1. Do not feed squirrels, chipmunks or other wild rodents.
- 2. Never touch sick, injured or dead rodents.
- 3. Do not camp, sleep or rest near animal burrows or areas where dead rodents are observed.
- 4. Look for and heed posted warning signs.
- 5. Wear long pants tucked into boot tops and spray insect repellent containing DEET on socks and pant cuffs to reduce exposure to fleas.
- 6. 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.
- 7. 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.
People who get sick after being in an area where plague is known to occur should call their doctor immediately, and tell their physician that they may have been exposed to the disease. 
 USA Today
 CBS News