The California Department of Public Health is investigating a case of human plague after a child contracted the rare disease while camping in Yosemite National Park.
Health officials are conducting an environmental evaluation in the Stanislaus National Forest, Yosemite National Park and surrounding areas to determine if the disease has spread.
The last reported human plague case occurred in California in 2006. But the announcement comes two days after Colorado health officials said an adult had succumbed to the plague in Colorado – the second in the state this year – after likely "contracting the disease from fleas on a dead rodent or animal."
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The department launched an investigation after the child, who is from Los Angeles County, fell ill and was hospitalized after visiting Stanislaus National Forest and camping at Crane Flat Campground in Yosemite National Park in mid-July, State Health Officer Dr. Karen Smith said.
The child's age, gender and name have not been released. None of the other campers have reported any symptoms. Health officials are continuing to monitor the child's family and treatment providers. The child is recovering, they said.
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 or humans, CDPH said.
“Although this is a rare disease, people should protect themselves from infection by avoiding any contact with wild rodents," Smith said. "Never feed squirrels, chipmunks, or other rodents in picnic or campground areas, and never touch sick or dead rodents. Protect your pets from fleas and keep them away from wild animals."
The CDPH is working closely with the Los Angeles County Department of Public Health, U.S. Centers for Disease Control and Prevention, Yosemite National Park and the U. S. Forest Service to pin down the source of the infection. The patient’s travel history and activities during the incubation period are also being reviewed.
Yosemite National Park is posting signs at the Crane Flat Campground and nearby campgrounds asking visitors to take precaution to prevent plague exposure.
Plague is not transmitted from human to human, unless a patient with plague also has a lung infection and is coughing. There have been no known cases of human-to-human infection in California since 1924. Health officials believe the risk of human-to-human transmission is low in this particular case. The last reported case of human plague in California can be traced back to 2005 and 2006 in Mono, Los Angeles annd Kern Counties. All three patients survived following treatment with antibiotics. Forty-two human cases of plague have been confirmed in California since 1970, of which nine proved fatal.
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, hiking 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 socks and pant cuffs to reduce exposure to fleas
• Keep wild rodents out of homes, trailers, and outbuildings and away from pets.
Early symptoms of plague: 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. Plague is treatable in its early stages with prompt diagnosis and proper antibiotic treatment. If not treated, plague can be fatal
Where can you find plague-infected animals in CA? In California, plague-infected animals are most likely to be found in the foothills and mountains and to a lesser extent, along the coast. Desert and Central Valley areas are considered low risk for plague. 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.
Information from CDPH was included in this report.