Health officials in California have confirmed that a resident of El Dorado County has tested positive for plague, a rare but potentially serious bacterial infection. The individual has been treated and is recovering at home, authorities said Friday.
The U.S. Centers for Disease Control and Prevention (CDC) reports that roughly seven Americans contract plague each year, with most cases occurring in western states such as California, Arizona, Colorado, New Mexico, and Nevada. Just last month, an Arizona man died after being infected.
El Dorado County health officials said the person was likely exposed to the infection while camping in a higher-elevation area. “Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County,” said Kyle Fliflet, the county’s acting public health director. The bacteria that cause plague, Yersinia pestis, are typically transmitted through the bites of infected fleas or by handling infected animals such as rodents, rabbits, squirrels, chipmunks, and even household pets like cats and dogs.
There are three main forms of plague: bubonic, septicemic, and pneumonic. Bubonic plague, the most common in the United States, primarily affects the lymph nodes, causing fever, weakness, and swollen glands. If untreated, the bacteria can spread into the blood, leading to septicemic plague, or to the lungs, causing pneumonic plague. The pneumonic form can be spread between people through droplets released by coughing or sneezing, making it the only type of plague considered contagious.
Dr. Scott Roberts, an infectious disease specialist at Yale University, noted that progression of the disease is not always predictable. “It’s not a hard-and-fast rule that plague progresses from bubonic to septicemic to pneumonic,” he explained. Vulnerable groups such as the elderly, young children, or those with weakened immune systems are at higher risk of severe illness.
Fortunately, modern antibiotics are highly effective against plague if treatment begins promptly. Left untreated, however, the disease can still be fatal. Public health experts emphasize the importance of early detection and care.
Animals also play a critical role in the spread of plague. While some species can carry low-level infections without showing symptoms, others—particularly cats—are more susceptible and can transmit the bacteria to humans. In regions where plague circulates widely, sudden die-offs of wild animals can increase human risk, as infected fleas seek new hosts.
To reduce exposure, health officials advise residents and visitors to avoid feeding or handling wild animals, use insect repellent when camping or hiking, and apply flea-control products to pets. Pet owners are also urged to prevent dogs and cats from roaming in rodent habitats.
Though plague may be best known for the devastating pandemics of the Middle Ages, experts stress that sporadic cases in the United States remain rare and manageable with proper medical treatment.