Valley fever, or coccidioidomycosis, is caused by a fungus that thrives in the soil of California's Central Valley and other arid parts of the West. Valley fever cases continue to rise in California and other states. In California's Central Valley, experts estimate that as many as 1 in 4 human pneumonia cases is valley fever. Climate change fuels the spread of valley fever fungusFor decades, valley fever was considered a disease of the Southwest. New valley fever treatments and vaccines offer hopeAntifungal drugs can suppress valley fever but not cure it.