Valley fever risk may be high this year, California officials warn in wake of music festival outbreak

California may be facing a particularly bad year for valley fever, health officials warn. The warning follows an announcement that several cases of the fungal disease were detected among attendees of a recent outdoor music festival near Bakersfield.

Valley fever, medically known as coccidioidomycosis, is a lung infection caused by Coccidioides, a fungus found in soil. The disease does not spread from person to person. People usually contract the illness by breathing in fungal spores from the environment, which leads to symptoms of cough, fever and shortness of breath. The infection can also cause night sweats, muscle aches and a rash on the upper body or legs.

Around 5% to 10% of people who catch valley fever develop long-term lung problems, and in about 1% of people who contract it, the infection can spread out of the lungs and affect the skin, bones, joints or brain. In these severe cases, the disease can be deadly. The infection can be treated with antifungal drugs.

Now, the California Department of Public Health (CDPH) is warning of a “potential increased risk for Valley fever” in the state this year. Many of the state’s valley fever cases are reported in the summer, so the department is aiming to raise awareness among the public and health care providers.

Related: New fungal infection discovered in China

California’s dry conditions, combined with heavy rains over the winter, could result in “increasing Valley fever cases in the coming months,” Dr. Tomás Aragón, director of the CDPH and the state’s public health officer, said in an Aug. 1 statement. “Individuals with lingering cough and fatigue should talk to a health care provider about Valley fever, especially if they have been outdoors in dusty air.”

Several cases of valley fever were recently flagged among people who traveled through Kern County to attend an outdoor music festival called Lightning in a Bottle, the CDPH reported in late July. The festival, held in mid-May near Bakersfield, drew more than 20,000 people. So far, the health department has identified five festival attendees who got valley fever, three of whom were hospitalized.

People who visited Kern County and are experiencing symptoms of a respiratory infection lasting longer than a week should visit a health care provider and ask about possible valley fever, the CDPH said. “Be sure to mention attendance at the music festival or travel to Kern County where Valley fever is common,” the CDPH noted. Affected festival attendees can also fill out a survey on the department’s website to aid in the investigation.

Symptoms of the disease can take one to three weeks after exposure to the fungus to show up, and they typically last weeks to months, or even longer in severe cases.

Most cases of valley fever reported in the U.S. are in Arizona and California, with about 10,000 to 20,000 total cases reported nationwide each year. Of those, about 200 cases are fatal.

In the past few years, California has reported about 7,000 to 9,000 cases a year. As of June, there have already been 5,370 cases this year — ahead of the count for the same period in 2023, when only 3,183 had been reported.

“Valley fever is on the rise in California, with particularly high numbers of cases reported in 2023 and 2024,” CDPH wrote in its July statement. The infection is most comm​on in the San Joaquin Valley and Central Coast areas of California, it noted.

Simple precautions can reduce the risk of getting valley fever in areas with high rates of the disease, according to the CDPH.

For instance, when it’s windy outside and the air is dusty, people can stay indoors and keep windows and doors closed, the CDPH recommends. People can also wet down the soil prior to digging projects to avoid stirring up dust into the air. Individuals may also consider wearing a properly fitted N95 respirator mask if they must be in dusty air outdoors in these areas.

This article is for informational purposes only and is not meant to offer medical advice.

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Nicoletta Lanese is the health channel editor at Live Science and was previously a news editor and staff writer at the site. She holds a graduate certificate in science communication from UC Santa Cruz and degrees in neuroscience and dance from the University of Florida. Her work has appeared in The Scientist, Science News, the Mercury News, Mongabay and Stanford Medicine Magazine, among other outlets. Based in NYC, she also remains heavily involved in dance and performs in local choreographers’ work.