The California Department of Public Health, along with Yosemite National park officials are investigating a possible second case of a person infected with the plague after visiting the park.

The CDPH has been notified of a presumptive positive case of plague contracted by a recent visitor to California from Georgia. Confirmatory testing is being conducted by the Centers for Disease Control and Prevention. Prior to becoming ill, the patient had been vacationing in Yosemite National Park, the Sierra National Forest and surrounding areas in California in early August. CDPH is in contact with Yosemite, CDC and the National Forest Service to assess locations where the patient visited.

This is the second suspected case of plague to originate from the national park. Earlier this month the CDPH announced that a child from Los Angeles County became ill and was hospitalized after visiting the Stanislaus National Forest and camping at Crane Flat Campground in Yosemite National Park in mid-July. The child is recovering from the disease.

Plague is an infectious bacterial disease that is carried by squirrels, chipmunks and other wild rodents and their fleas. When an infected rodent becomes sick and dies, its fleas can carry the infection to other warm-blooded animals including humans.

Health officials have confirmed the presence of plague in wild rodents at Crane Flat and Tuolumne Meadows campgrounds in Yosemite over the last two weeks, but said the risk to human health is low.

Just last week the park service closed both campgrounds to treat the area for fleas. Crane Flat has re-opened, while Tuolumne Meadows is still closed. All other areas in and campgrounds in Yosemite are open.

“Although this is a rare disease, and the current risk to humans is low, eliminating the fleas is the best way to protect the public from the disease,” said CDPH Director and State Health Officer Dr. Karen Smith. “By eliminating the fleas, we reduce the risk of human exposure and break the cycle of plague in rodents at the sites. People can protect themselves from infection by avoiding any contact with wild rodents.”

In addition to the treatments, park visitors are being notified by Yosemite officials of camp treatments, possible plague risks and are being provided information on how to prevent plague transmission. The CDC also has notified CDPH that recent communications about plague enabled health care providers in Georgia to make the diagnosis more quickly.

“The California Department of Public Health and Yosemite National Park were very proactive in their campaign to educate visitors about plague,” said Dr. Smith. “Warnings issued in California regarding plague were useful all the way across the country in Georgia. Those warnings helped the patient get the prompt medical attention necessary to recover from this illness.”

Early symptoms of plague may include high fever, chills, nausea, weakness and swollen lymph nodes in the neck, armpit or groin. People who develop these symptoms should seek immediate medical attention and notify their health care provider that they have been camping or out in the wilderness and have been exposed to rodents and fleas.

In California, plague-infected animals are most likely to be found in the foothills and mountains and to a lesser extent, along the coast. State and local health officials regularly monitor plague-prone areas by testing animals and their fleas. In 2014, non-human plague activity was detected in animals in seven counties:  El Dorado, Mariposa, Modoc, Plumas, San Diego, Santa Barbara and Sierra.

Human illness with plague is rare in California. Prior to 2015, the last reported cases of human plague in California occurred in 2005 and 2006 in Mono, Los Angeles and Kern counties and all three patients survived following treatment with antibiotics. Plague is not transmitted from human to human unless a patient with plague also has an infection in the lungs and is coughing.

Steps the public can take to avoid exposure to human plague include:

·         Never feed squirrels, chipmunks or other rodents and never touch sick or dead rodents.

·         Avoid walking or camping near rodent burrows.

·         Wear long pants tucked into socks or boot tops to reduce exposure to fleas.

·         Spray insect repellent containing DEET on skin and clothing, especially socks and pant cuffs to reduce exposure to fleas.

·         Keep wild rodents out of homes, trailers, and outbuildings and away from pets.