Coccidioidomycosis (also called Valley fever or “cocci”) is a disease caused by inhalation of the spores of the Coccidioides fungus that grows in the soil and dirt in some areas of the southwestern United States, with 97% of cases reported in Arizona and California. Anyone who lives, works, or travels in areas where coccidioidomycosis has been reported can become infected, particularly people exposed to dirt and dust outside. Coccidioidomycosis typically causes a mild, self-limited respiratory illness or pneumonia but can lead to severe disseminated disease and, in rare cases, death.

In California, the number of reported coccidioidomycosis cases has increased from less than 1,000 cases in 2000 to more than 9,000 cases in 2019. Each year, coccidioidomycosis contributes to the hospitalization of approximately 1,000 Californians and 80 deaths.