At least 19 people contract fungal infection after California music festival, officials say

At least 19 people contracted valley fever, a fungal infection that in rare cases can be fatal, after attending an outdoor music festival in southern California in May, public health officials have reported.

The number of illnesses associated with the five-day Lightning in a Bottle event has almost quadrupled over the last month. Valley fever is caused by inhaling Coccidioides, a fungus endemic to the soil of the US south-west. New research shows that cases of the illness have risen dramatically in recent years.

It typically presents as a mild respiratory illness – most people will not become ill after an exposure – but a small subset of those infected can develop serious, debilitating or long-term problems.

More than 20,000 people attended Lightning in a Bottle, an electronic dance music festival, in Kern county between 22 and 27 May, according to the California department of public health. Nineteen people have confirmed diagnoses of the illness through a voluntary survey, including eight who were hospitalized, the CDPH said in a statement last month.

Valley fever has been increasing in California, particularly in the central area of the state, for years as the climate crisis has rendered the landscape drier and hotter – conditions the fungus favors.

Between March 2000 and February 2021, there were 89,281 reported cases in 17 counties, according to a study published this year. There were 12 times as many incidents across counties in the state in 2018 than in 2000, according to the study. Since 2014 alone, reported cases in the US have almost doubled, and in California they have more than tripled.

There were more than 9,000 cases reported in the state last year, and more than 5,000 preliminary cases reported as of July 2024, the CDPH reported. The state public health department said the increase could be attributed to winter rains following years of drought, increased recognition and testing for the disease, and more “soil disturbance activities” in areas with a high risk.

Coccidioides grows in the dirt but can be become airborne when disturbed and can travel miles away.

Most people do not become ill after exposure to the fungus, but for those who do, experts have said that it is likely very few actually receive a valley fever diagnosis. Of those infected, about 40% of people develop a respiratory illness that can be mild while 1% have more severe outcomes, the Guardian reported in 2022.

The California department of public health warns that the Central valley and central coast may face increased risk of valley fever through fall.

“We’re preparing for another possible increase in valley fever cases in the coming months, and we want Californians to know the signs and symptoms to detect it early,” Dr Tomás Aragón, the state public health officer, said in a statement. “If you have a lingering cough and fatigue, please talk to a doctor about valley fever, especially if you’ve been outdoors in dusty air in the Central valley or central coast regions.”