Cases of Valley fever rose statewide in 2024, data from the California Department of Public Health shows, with some places seeing spikes of over 100% year over year.
Valley fever, which is caused by inhaling fungal spores found in soil, is a potentially deadly respiratory infection marked by symptoms like cough, fever, chest pain and difficulty breathing. In severe cases, the disease can infect the brain and cause meningitis or even death. Although most cases of the disease originate in the state’s central regions, cases have been reported in areas like the northern Central Valley and Southern California.
CDPH’s statewide Valley fever database, which is updated with cases confirmed through Nov. 30, found cases increased year-over-year in Alameda, Contra Costa, Fresno, Kern, Kings, Los Angeles, Madera, Merced, Monterey, Riverside, Sacramento, San Diego, San Francisco, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Solano, Sonoma, Stanislaus, Tulare and Ventures counties. In counties like San Francisco, the increase was modest due to the low number of overall cases: 24 confirmed cases in 2023 compared to 50 this year.
The largest year-over-year percentage increase was in Monterey County, which saw 96 cases in 2023 and 299 this year, a jump of over 200%. Due to its location in the hot, dusty Central Valley, and its number of agricultural workers, Kern County has the most cases in California by far. Of the state’s 11,076 cases, 3,768 were logged in Kern County.
Earlier this year, at least 19 people tested positive for Valley fever after attending the Lightning in a Bottle music festival near Bakersfield, according to CDPH. Eight of those people were hospitalized.
People who are frequently exposed to dirt and dust in areas where the disease is present are more likely to contract it, a factor that puts California’s farmworkers especially at risk of Valley fever. CDPH recommends that those at risk take precautions like keeping doors and windows closed when it is windy or dusty outside, wetting down soil before digging and wearing N95 masks when outside in dusty areas.
By Katie Dowd, Sam Mauhay-Moore from SFGATE