Valley Fever Cases Surge in California

Health

Aug 19

California is in the midst of a record-breaking spike in Valley Fever cases, with state health officials sounding alarms as infections continue to rise—particularly in areas like San Joaquin County and Lodi. Through July of this year, California has already logged 6,761 cases, putting 2025 on track to surpass last year’s record of 12,500 cases[1]. That’s a dramatic jump from an average year just a decade ago, and a far cry from the fewer than 1,000 cases the state saw in 2000[3].

Valley Fever Cases across California, 2000 - 2025.

Rising Threat Reaches New Areas

Valley Fever, a fungal disease usually found in the southern Central Valley, has expanded well beyond its historical boundaries. Kern County remains the hardest-hit, tallying 1,945 cases in the first seven months of 2025. However, counties like Monterey have seen an astonishing surge, jumping from just 47 cases in 2023 to 344 this year—a more than 600% increase. [2] San Joaquin County has not been spared; nearly 246 cases have already been reported locally, compared to just 47 two years ago[4].

Central Valley counties, including San Joaquin, Merced, and Stanislaus, are all seeing higher numbers. The Central Coast and parts of Northern California, which were previously considered low-risk areas, are now joining the endemic zone as Valley Fever continues to spread[5].

Valley Fever Cases by County, 2023 - 2025

What’s Driving the Surge?

Experts blame the increase on California’s changing climate. Alternating cycles of drought followed by wet winters have created perfect conditions for the Coccidioides fungus. As summers grow hotter and drier, winds whip up dust containing fungal spores, allowing them to travel farther than ever before. Construction, agriculture, and any disturbance of dry soil further help the fungus spread[7].

Lodi and Tracy: Areas of Special Concern

Locally, Lodi and Tracy are seen as “areas of special concern,” say San Joaquin County health officials. New home construction, farming, and windy conditions all contribute to rising risk. The area’s development boom disturbs soil where the Valley Fever fungus can lurk, sending spores airborne and increasing exposure[4].

How Dangerous Is Valley Fever?

For most people, Valley Fever is mild, and about 60% of cases resolve on their own without medical intervention. But for some—including older adults, pregnant women, those with weakened immune systems, and people of color with increased risk for severe disease—the infection can become serious, even life-threatening[5].

Doctors typically prescribe antifungal drugs, with fluconazole and itraconazole the mainstays of treatment. Amphotericin B is reserved for severe cases. However, growing resistance to these medications is a troubling trend, with some strains of the fungus failing to respond as well as in the past[10].

Can Valley Fever Be Prevented?

There’s no vaccine yet, but residents can reduce their risk by taking precautions—especially during hot, dusty months:

Wear N95 masks outdoors on windy days and construction sites.
Keep windows closed while driving through dust storms.
Limit outdoor activities when dust levels are high.
Seek medical attention if breathing problems last more than a week[12].

Officials emphasize that everyone should watch for a persistent cough, fever, or fatigue that doesn’t improve. Valley Fever can mimic other illnesses, such as COVID-19 and the flu.

Looking Ahead

With climate trends unlikely to reverse, San Joaquin County—and Lodi in particular—will likely face continued increases in Valley Fever cases. Health experts urge residents and local healthcare providers to remain vigilant throughout the fall, when infections tend to peak. As California’s endemic zone expands, the focus is shifting to new treatments and improved ways to protect our most vulnerable community members. [1]

Valley Fever may once have been a Central Valley problem, but it’s now a statewide—and local—concern.