An outbreak of valley fever among attendees and workers at an outdoor music festival in California’s Central Valley has highlighted the growing threat of fungal infections.
Fourteen people who traveled to Bakersfield to attend or work at the Lightning in a Bottle festival in May have tested positive for valley fever and developed symptoms, the California Department of Public Health told NBC News on Thursday. At least three people have been hospitalized.
“About a week after I got back from the festival, I got really bad body aches and fever,” said Eric Mattson, 33, a musician from San Luis Obispo who attended this year’s festival after testing positive for valley fever last month.
The condition progressed to joint pain, difficulty moving and night sweats. “I would wake up two or three times in the night drenched in sweat. I had to change my bedding and pyjamas in terrible pain. It was really bad,” Mattson said.
Most cases of Valley fever have been identified in Arizona and California because the bacteria that causes it, Coccidioides, thrives in hot, dry climates. As climate change creates more opportunities for the bacteria to thrive, Valley fever cases in California are on the rise.
“The number of reported valley fever cases has been particularly high in 2023 and 2024, which may be related to heavy rains in the winter of 2022-2023 following several years of drought,” the health department said in a statement.
California’s annual case count has risen from fewer than 1,000 in 2000 to more than 9,000 in 2019. There have been 5,370 suspected or confirmed cases so far this year, according to a recent report from the state health department.
San Joaquin County has already seen more than 200 suspected and confirmed cases combined this year, 47 overall last year and 59 so far in 2022.
Valley fever is not transmitted from person to person. Rather, it infects the lungs by inhaling spores in dust or soil. The name comes from the San Joaquin Valley, where Coccidioides was found.
Mattson said he hasn’t been contacted by the California Department of Public Health, which has not released the names of the 14 people who have been confirmed to be infected, so it’s unclear if Mattson is among them. NBC News has reviewed Mattson’s medical records, which show he tested positive.
Mattson estimated he lost 20 pounds in four to five weeks.
He suspected valley fever, having heard reports of some festival-goers being infected in the past, but was initially diagnosed with pneumonia. Eventually, his doctor ordered a blood test, which came back positive early last month.
Mattson’s situation is common, says Dr. Geeta Sivasubramanian, an assistant professor of clinical medicine at the University of California, San Francisco, Fresno: “Patients with valley fever are often misdiagnosed with bacterial pneumonia.”
That’s because many doctors don’t recognize the disease, test for it too early, or confuse it with other respiratory infections, she says — errors that can lead to patients receiving unnecessary antibiotics instead of the appropriate antifungal medication.
About 60% of people with valley fever have no symptoms, but some may experience symptoms such as cough, fatigue, fever, shortness of breath, night sweats, muscle and joint pain, and a rash on the legs and upper body. People with diabetes, weakened immune systems, and pregnant women are more susceptible to severe lung infections. In very rare cases (about 1%), the lung infection can spread to the bones, joints, and brain, becoming life-threatening.
An ideal environment for spreading valley fever
Sivasubramanian said he wasn’t surprised by the concentration of cases among the more than 20,000 people attending the music festival.
“We live in a valley fever endemic area so anyone who visits the area or lives in the area is at risk,” she said.
In the Central Valley, heavy winter rains encourage the growth of the fungus in the soil, then as temperatures rise and the soil dries, dust carries the spores into the air.
Activities that kick up large amounts of dust, such as construction and agriculture, increase the risk of exposure; in 2014, the Centers for Disease Control and Prevention linked five confirmed and five suspected cases of valley fever to the dry, dusty conditions of outdoor film sets.
Dr. Arturo Casadevall, chair of the department of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health, said “Lightning in a Bottle” appears to have come to the right place at the right time.
“You need two things: a spore cloud and a human,” he said.
Mattson said high winds during the festival stirred up dust near some of the stages and in the campgrounds where many attendees stayed.
“When you have a lot of people dancing, it definitely kicks up a lot of dust,” he said.
Valley fever may be spreading to new areas
Climate change is bringing increased rainfall and warmer temperatures, which create favorable conditions for the fungus to thrive, and more frequent and severe wildfires could carry spores to surrounding areas.
A 2019 study estimated that outside of California and Arizona, valley fever may already be endemic in certain counties in 10 eastern states, including Kansas and Oklahoma.
“As the desert expands, we’re going to see cases outside of the historic areas,” Casadevall said.
Some researchers suspect that climate change may be altering rodent migration patterns, helping the fungus spread, but others think it’s not common: A 2022 study found Coccidioides in rodents in Kern County, home of the Lightning in a Bottle festival.
Mattson said she doesn’t regret attending the festival, but she wants people in the community to know about the disease and its symptoms.
“If you’ve been in the valley or been anywhere where there’s a lot of dust in the air, we really want to encourage people to get tested,” he said.
This article originally appeared on NBCNews.com.
