The fungus that causes “Valley Fever” (coccidioidomycosis) has been detected in soil samples in Washington, much further north than its expected range, for the first time.
The Valley Fever fungus, called Coccidioides, is typically found in the semiarid climates of the southwest U.S., 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. Inhaling the fungus can make people sick with flu-like symptoms or severe infections.
The state Department of Health received reports of three unrelated cases of Valley Fever in residents of Walla Walla, Benton and Franklin counties. These people hadn’t 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.
Test results on soil samples from the most likely exposure areas were positive for the Valley Fever fungus, and the cultures genetically matched samples of the fungus obtained from one of the patients. This confirmed that the patients were exposed in Washington.
Valley Fever fungus had 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. State public health officials 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.”
Because Valley Fever can also affect animals, an advisory was also 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.