Cases of a lung infection known as Valley fever are on the rise in the northern Central Valley and Central Coast regions of the state, the California Department of Public Health warns.
“California had a record year for Valley fever in 2024 and case counts are high in 2025,” said CDPH director and state public health officer Erica Pan.
Valley fever, also known as coccidioidomycosis, is an illness caused by breathing in fungal spores that grow in the soil. When soil containing the fungus is disturbed by digging or high winds, tiny fungal spores can get into the air.
It is named after the San Joaquin Valley where it is most common, but reported cases have seen an increase in the northern Central Valley and the Central Coast areas, according to the state health department. Cases are also most common in the Southwest region of the U.S., especially in Arizona, according to the federal Centers for Disease Control and Prevention.
The illness is not contagious and cannot be spread through contact with an infected person. Animals, including dogs and cats, can also contract Valley fever.
Infection can cause respiratory symptoms similar to influenza and COVID-19, such as fever, cough, body aches, chest pain, and having trouble breathing. In severe cases, it can cause rashes, skin lesions and chronic lung issues.
It is also an under-diagnosed or misdiagnosed disease because its symptoms resemble other illnesses that are more common.
While 60% of those exposed to the spores can fight off the infection and not experience symptoms, severe cases can require hospitalization or even be fatal. In California, about 1,000 people are hospitalized every year for the illness and on average, 10% of those hospitalized die, according to the CDPH.
August is Valley Fever Awareness Month
August, when cases typically see an uptick across the state, is Valley Fever Awareness Month. Most infections occur during the drier seasons like late summer and fall, but it can be contracted at any time of the year.
While 2024 was the highest year on record for Valley fever with nearly 12,500 cases in the state, so far this year CDPH is already seeing the number of provisional cases surpass 2024 totals in certain counties. “Provisional” cases include suspected, probable, and confirmed cases of Valley fever.
As of July 31, there were a total of 6,761 provisional cases of Valley fever in California.
Compared to the number of cases in 2024, so far this year the department has recorded increases in provisional Valley fever cases in places such as Monterey, San Joaquin, Merced, Contra Costa, Fresno, and Stanislaus counties.
Monterey County has seen the greatest percent change statewide in provisional cases compared to the 2023 to 2024 average. In 2023, there were 47 provisional cases in the county, compared to 344 so far this year.
People over the age of 60, pregnant women, diabetics, and people with weakened immune systems are most at risk for developing severe symptoms if they become infected. Research has also found that African Americans and Filipino Americans are at a higher risk of severe disease from Valley fever, which may relate to underlying health conditions or health inequities, according to the state health department.
Laborers and people who have been in proximity to construction or landscaping sites where dirt has been dug up are also at a higher risk for contracting the illness.
When to see a doctor
CDPH advises that people see a doctor is they experience Valley fever symptoms for over one week.
“If you have been sick with symptoms like cough, fever, trouble breathing, and tiredness for more than 7 to 10 days, please talk to a health care provider about Valley fever, especially if you’ve been outdoors in dusty air in the Central Valley or Central Coast regions,” Pan said.
READ MORE
I contracted Valley fever. I could have died — A Local News Matters editor shares his personal story.
People who live, work, or travel in areas where Valley fever is common should stay indoors with shut windows if it is windy outside. If driving through a dusty area, keep the windows shut and use recirculating air inside the car. Wearing an N95 mask can also help as a barrier against breathing in the fungal spores that cause the infection.
“Valley fever is a serious illness that’s here to stay in California,” Pan said.” We want to remind Californians, travelers to California, and their health care providers to watch for signs and symptoms of Valley fever to help detect it early.”
A statewide Valley fever dashboard showing data for provisional cases in 2025 as of July 31 can be found on the CDPH website.
The post Valley fever on the rise: Cases of dangerous fungal infection spread throughout California appeared first on Local News Matters.