In a follow-up to the report of a Los Angeles County child who contracted plague at Yosemite National park California Department of Public Health (CDPH) officials say the Crane Flat Campground in Yosemite, which has been closed for flea treatment for the past several days, has reopened today.

Oriental rat flea, Xenopsylla cheopis/CDC

The CDPH announced that next week, the Tuolumne Meadows Campground in Yosemite will be closed from Monday-Friday next week for similar treatment after discovering  new evidence of plague activity in animals.

This flea treatment is commonly used to protect wildlife, pets and human health from this disease.

Although the presence of plague has been confirmed at Crane Flat and Tuolumne Meadows campgrounds, the risk to human health remains low. Action to protect human and wildlife health by closing and treating campgrounds is being taken out of an abundance of caution. Campground visitors are being notified by Yosemite National Park of camp treatments, possible plague risks and provided information on how to prevent plague transmission. An investigation into a case of human plague in California, and environmental evaluation in the Stanislaus National Forest, Yosemite National Park and the surrounding areas led to these actions.

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.

“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,” she added.

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.

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 a lung infection and is coughing.

Robert Herriman is a microbiologist and the Editor-in-Chief of Outbreak News Today

Follow @bactiman63

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