Valley Fever or Coccidioidomycosis is an infectious disease caused by fungus called Coccidioides; the fungus lives in soil in the deserts of the southwestern US, and some parts of Mexico and Central and South America. People can be easily exposed to the fungus when the soil is disturbed, such as by storms, fires, construction, agricultural activities, or recreation, for some examples. When the fungal spores are inhaled, Coccidioidomycosis may arise.
Not everyone who inhales the fungal spores of Coccidioides will get sick, because the immune system can often fight off these infections on its own. But about one-third of people who inhale these spores end up with a lung illness. The symptoms, like coughing and fever, can resemble many other illnesses like a cold or flu. In a few cases, the infection will have impacts outside of the respiratory system; it can go on to affect the skin, joints, and central nervous system.
The illness can be avoided by staying away from blowing dirt or desert dusts, wearing masks, and spreading awareness. Right now, there are no treatments specifically for Coccidioidomycosis. Some antifungal drugs can be used for these infections, but they usually come with side effects including hair loss, dry skin, vomiting, and nausea.
The rates of the disease seem to be on the rise. Already this year, there have been 3,123 confirmed cases of Valley fever in California, which is about double the typical amount for this first-quarter period and this area, compared to a ten-year average. In the first-quarter period of 2016, there were only 801 cases in California; in 2024 there were 3,011 cases during that period in the state.
Increases in the incidence of Valley fever seem to follow a pattern: when there are several years with below average precipitation that are followed by a wet winter, and then an arid summer, the rates of Valley fever spike for about two years, noted Doua Ge Yang, the California Department of Health spokeswoman. The state saw a pattern like this in 2023, and then in 2024 the 12,637 cases that were recorded that year was the highest ever annual total.
"We actually had sort of seen this coming, just based on the climate cycle of the last few years," said fungal infection expert George R. Thompson, a professor of medicine at the UC Davis School of Medicine.
Right now, officials don't know if these high rates of Coccidioidomycosis will persist, but people should stay vigilant and protect themselves from blowing dust. This is particularly true for regions with new development and housing, and which were recently uninhabited. These areas tend to be dry and dusty.
A five-day music and arts festival called Lightning in a Bottle was held in Kern County, California last year, and at least nineteen people got Valley fever there. The festival will be held at the same location this year, and the organizers have said that they will try to reduce dust levels with water and artificial turf.
Although the evidence is only anecdotal at this time, some clinicians have wondered whether the infection is getting more severe, and if some of the antifungal drugs used for the illness are not working as well.
The state of California and university partners are planning to study a possible link between the use of antifungal chemicals in agriculture and rising drug resistance in Coccidioides. Work on this infection has been a lower priority in recent years because of other major infection outbreaks.
Sources: CDC, Cleveland Clinic, LA Times
