Valley Fever Alert: 14 Festival-Goers Affected by Growing Fungus Threat

A recent Valley fever outbreak among attendees and workers at an outdoor music festival in California’s Central Valley underscores the growing risk of this fungal infection.

Fourteen individuals who traveled to the Lightning in a Bottle Festival in Bakersfield in May have tested positive for Valley fever, according to the California Department of Public Health. At least three of these people required hospitalization.

Eric Mattson, a 33-year-old musician from San Luis Obispo, reported severe body aches and fevers about a week after attending the festival. He was later diagnosed with Valley fever and experienced worsening symptoms including joint pain and night sweats, leading to significant weight loss.

The fungus responsible for Valley fever, known as coccidioides, thrives in hot, dry climates. Consequently, most cases are reported in Arizona and California. With climate change creating favorable conditions for the fungus, cases of Valley fever are increasing in these areas.

The California Department of Public Health noted that preliminary reports show a high number of Valley fever cases in 2023 and 2024, potentially due to heavy winter rains in 2022-2023 after a period of drought. The number of annual infections in California rose from fewer than 1,000 in 2000 to over 9,000 in 2019. This year, there have already been 5,370 suspected or confirmed cases.

In San Joaquin County, the number of cases has exceeded 200 this year alone, compared to 47 last year and 59 in 2022.

Valley fever is not transmitted from person to person. Instead, it is contracted by inhaling spores from dust or soil. The condition is named after the San Joaquin Valley, where the fungus was first identified.

Mattson has not been contacted by the health department, and it is unclear whether he is one of the 14 confirmed cases. His positive test result has been verified by NBC News.

Mattson reported losing 20 pounds over four to five weeks and was initially misdiagnosed with pneumonia before a blood test confirmed Valley fever.

Dr. Geetha Sivasubramanian from UCSF Fresno highlighted that many cases of Valley fever are often mistaken for bacterial pneumonia due to a lack of awareness among doctors. Misdiagnosis can lead to unnecessary antibiotics instead of the proper antifungal treatment.

Approximately 60% of those infected with Valley fever are asymptomatic, while others may experience cough, fatigue, fever, shortness of breath, night sweats, muscle aches, joint pain, or a rash. Individuals with diabetes, weakened immune systems, or those who are pregnant are at greater risk for severe infections. In rare cases, the infection may spread to bones, joints, or the brain, which can be life-threatening.

Dr. Sivasubramanian was not surprised by the outbreak among the festival’s 20,000 attendees. She noted that living in or visiting areas with high Valley fever prevalence poses a risk.

In the Central Valley, winter rains promote fungal growth in the soil, and as temperatures rise and the soil dries, dust carries the spores into the air. Activities like construction and farming that stir up dust increase the risk of exposure. In 2014, the CDC linked cases of Valley fever to dusty conditions on a film set.

Dr. Arturo Casadevall from Johns Hopkins University remarked that the festival's location and timing were ideal for an outbreak. Dust was stirred up by the wind and large crowds at the festival.

Climate change, which leads to heavier rains and higher temperatures, creates favorable conditions for the coccidioides fungus. Increased wildfires may also spread spores to new areas.

A 2019 study suggested that Valley fever could be endemic in counties across 10 other states, including Kansas and Oklahoma. As deserts expand, the disease may spread beyond traditional regions.

Some researchers speculate that climate change might alter rodent migration patterns, potentially aiding in the fungus’s spread. A 2022 study found coccidioides in rodents in Kern County, where the festival was held.

Mattson has no regrets about attending the festival but encourages others to be aware of Valley fever and get tested if they are exposed to dusty environments.