NEWS | BAY AREA & STATE
'They're not going to live normally': A devastating disease has surged in Calif.

By Gillian Mohney,
News Editor
Aug 18, 2025


Valley fever, or coccidioidomycosis, is spread when spores from a naturally occurring fungus are inhaled.
The Washington Post/Getty Images

In just 25 years, cases of an uncommon but potentially devastating disease have climbed more than 1,200% in California. … This month, the California Department of Public Health reported that Valley fever cases are on track to surpass last year’s record number of over 12,500 cases.



Muted backlit silhouette of two tractors raking soil in California’s San Joaquin Valley.
Getty Images/iStockphoto

The infection, caused when people inhale spores of the naturally occurring Coccidioides fungus, made up fewer than 1,000 cases back in 2000 in California.
Shaun Yang, the director for molecular microbiology and pathogen genomics at the UCLA Department of Pathology and Laboratory Medicine, said relatively mild and wet winters in much of California mean the fungus can thrive underground without being killed off by frost. … “This kind of very wet and dry pattern definitely is perfect for this fungus to grow,” Yang told SFGATE.

In recent years, climate change has supercharged years of drought and rainfall in California, and Yang says these changes may be a big reason for the spike in cases. In dry weather, the spores spread as dry dust and soil are kicked up because of construction, agriculture or wind.

“I think climate change is the main reason to explain this type of dramatic explosion,” Yang told SFGATE. “I don’t think anything else can explain this type of phenomenon.”

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