Valley fever fungus found in Washington soil samples

The fungus that causes valley fever has been detected for the first time in Washington soil samples, much further north than its expected range.

The valley fever fungus, called Coccidioides, is typically found in the semiarid climates of the southwest United States, such as Arizona and California, and in Central and South America. The fungus lives in the soil and its spores can be breathed in when dirt is disturbed by digging, excavating, or dust storms, State Department of Health staff said.

Inhaling the fungus can make people sick.

In 2010 and 2011, the Washington Department of Health received reports of three unrelated cases of Valley Fever in residents of Walla Walla, Benton, and Franklin counties. These people had not recently traveled out of state.

An investigation conducted by local and state health officials determined that these patients were most likely exposed in south-central Washington. The Department of Health and Benton-Franklin Health District collected and preserved soil samples from the suspected exposure locations in Benton County.

The Centers for Disease Control and Prevention (CDC) along with colleagues at Translational Genomics Research Institute in Flagstaff, Arizona, recently developed the first method to test soil samples for the fungus. Test results showed that the soil samples were positive for the valley fever fungus, and that these cultures genetically matched samples of the fungus obtained from one of the patients. This confirmed that the patients were exposed in Washington.

These findings are important because the valley fever fungus has never before been found in Washington soil. However, DNA analysis suggests that the fungus has been here for a while.

There is still much to learn about the extent of this fungus in the environment in Washington. Yet, state public health officials want to remind people that only a few cases of valley fever are reported among Washington residents each year, and nearly all who develop the illness have recently traveled to the southwest or Mexico.

“The risk of getting the disease in Washington appears to be very low, and we’re working with local health partners to track and investigate cases of the disease,” said State Health Officer Dr. Kathy Lofy at the Department of Health. “We’re developing a plan for additional soil testing, which we hope will provide us with a better understanding of the environmental conditions that support the growth of the valley fever fungus in our state.”

The Department of Health is working with local public health agencies and the CDC to notify health care providers about the potential for locally-acquired valley fever. The agency has notified health professionals and laboratories, asking them to report cases and send positive cultures to public health officials. Because valley fever can also affect animals, the advisory was sent to veterinarians statewide. Reporting human and animal illnesses helps health officials identify and investigate potential in-state exposure sites.

Most people exposed to the valley fever fungus don’t become ill, but some develop a mild flu-like illness with fever, cough, headache, and body aches or pneumonia. Less commonly, people can develop more severe infections including meningitis, bone or joint infections, skin lesions, or chronic pneumonia.

Health care providers can test and treat patients with antifungal medications, though mild illnesses often get better without any treatment. The disease is not spread from person-to-person.

Information from the Department of Health is included in this report.

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