California is seeing a spike in Valley Fever cases this year, and health experts are raising concerns. By the end of July 2025, the California Department of Public Health (CDPH) reported 6,761 cases, and if the trend continues, the state could break last year’s record of 12,595 cases.
Valley Fever, also called coccidioidomycosis or “cocci,” is caused by a fungus that lives in the soil. It has been slowly increasing in the US over the past two decades. In 2000, fewer than 1,000 cases were reported annually, but by 2019, that number had jumped to over 9,000. Experts warn that environmental changes, like increase in temperature and dry, dusty conditions, could make the disease more common in the coming years.
The CDPH also recently pointed to a music festival as a possible trigger for last year’s surge. The popular outdoor event at Buena Vista Lake, California, from May 21 to 25, 2024, brought thousands together. Officials have warned that some people may have been exposed to the fungus, which spreads through dust and soil.
What Is Valley Fever?
The fungus responsible for Valley Fever thrives in dry, dusty soils across California and other southwestern states. According to the Centers for Disease Control and Prevention (CDC), humans and animals can contract the infection by inhaling airborne spores, which settle in the lungs.
Symptoms of Valley Fever
Valley Fever can range from mild to severe. Symptoms include fatigue, cough, fever, night sweats, and body aches. In some cases, it can progress to pneumonia or spread to bones or the brain, leading to long-term health issues. “Symptoms usually show up 1 to 3 weeks after inhaling the spores. While some people don’t notice any symptoms, others may feel like they have the flu,” explains Dr Suranjit Chatterjee, Senior Consultant, Internal Medicine, Indraprastha Apollo Hospitals. “Typical signs include fever, cough, chest pain, tiredness, headache, and muscle aches.”
Who is at risk of Valley Fever?
As per CDC, certain people are more vulnerable, including pregnant women, people over 60, those with weakened immune systems, diabetics, and workers frequently exposed to dust, like those in construction or agriculture. Around 1 percent of infected patients may experience a serious infection that spreads beyond the lungs to the skin, bones, joints, or brain. Meanwhile, 5 to 10 percent could suffer lasting lung complications. While mild cases may resolve on their own in weeks or months, severe infections often require antifungal medication and hospitalisation.
What triggered Valley Fever in 2025?
As per CDPH and CDC, climate change and environmental factors are responsible for this year’s spike in Valley Fever cases. Warmer, wetter winters followed by dry, windy weather create the perfect conditions for the fungus to grow. When dust is stirred up by windstorms, construction, or farming, the spores get into the air and can be inhaled, leading to Valley Fever.
While the infection used to be mostly seen in the San Joaquin Valley, cases are now rising in coastal and Central Valley areas, including Monterey and Ventura counties.
Precautionary tips
Both the California Department of Public Health (CDPH) and the CDC advise staying indoors on windy, dusty days and keeping windows and doors closed. Preventing Valley Fever is especially important if you live in or travel to areas where the fungus is common. Dr Suranjit Chatterjee recommends some simple steps: avoid dusty areas whenever possible, stay indoors during dust storms or high winds, and wear N95 masks or other protective gear if you work in construction, farming, or outdoor cleaning.
He also advises keeping windows and doors shut on windy days and wetting the ground before digging to reduce dust exposure. Valley Fever can’t be spread from person to person, but early treatment can help you feel better faster and avoid complications.
With changing weather and more dust in the air, experts say Valley Fever could keep becoming a bigger health problem in California.