Valley fever is on the rise in San Mateo County

Coccidioidomycosis, the scientific name for valley fever, is a fungus found in drier parts of the nation including southern Arizona, central California, southwestern New Mexico, and west Texas, that causes about 20,000 infections a year, according to the county’s report. 

Of those infections, about 97% come from Arizona and California with highest infection rates originating in the Central Valley, according to the report. About 1,000 Californians are hospitalized and 80 die due to the infection annually, the report read. But officials warn that cases are beginning to increase in other parts of the state, specifically the Northern San Joaquin Valley and coastal parts of Southern California. 

Cases statewide tripled between 2014 and 2018 and grew from fewer than 1,000 cases in 2000 to more than 9,000 cases in 2019, the report read. San Mateo County has also seen cases more than triple from last year’s report from three reported cases to 11. 

“Although we have seen an increase in the number of coccidioidomycosis (valley fever) cases in San Mateo County, it is difficult to say if they were exposed to the organism within the county or somewhere else in California,” Health Officer Dr. Kismet Baldwin-Santana said in a statement. “We are communicating with health care providers in the community that valley fever is something they should consider if patients present with symptoms consistent with the illness.”

Valley fever is caused by breathing in fungus spores and symptoms may appear one to three weeks after exposure, including fatigue, cough, fever, shortness of breath, headache, night sweats, muscle aches or joint pain and rashes on the upper body or legs, according to the Centers for Disease Control and Prevention. 

Symptoms can last from a week to a few months and typically go away without treatment but more extreme cases may require anti-fungal medication. More long-term cases typically occur in about 5%-10% of those who contract the infection. Valley fever cannot be spread between people except for in very rare occasions when someone comes into contact with a wound with coccidioidomycosis, according to the CDC. 

Baldwin-Santana said there are currently no definitive reasons for why cases have increased recently but said research by the University of California, Berkeley, and the California Department of Public Health shows that coccidioidomycosis becomes less active during dry conditions like droughts but grows when rains return. After experiencing years of drought, extreme rainstorms hit the county earlier this year, a pattern triggered by climate change experts warn could lead to continuing increases in valley fever, according to the county report. 

“Historically, cases in California have been lowest during years of drought and highest during years immediately after a drought,” the report read. “The wet winter season California experienced this year could lead to more cases this summer and fall and experts worry that climate change may influence the endemic area of coccidioidomycosis and the number of cases in the United States.”