Within the last year, Kern County has seen an increase in Valley Fever cases, with 3,990 recorded cases and 49 deaths compared to 2023. The fungal infection is caused by inhaling Coccidioides spores, which primarily target the lungs but can also spread to other parts of the body.
These spores are commonly found in soil and can become airborne through construction, agricultural work, or wind.
When asked if the fungus could ever be eliminated from Central Valley soil, Dr. Carlos D’Assumpcao, MD, an infectious disease physician at the Valley Fever Institute in Kern County, explained that “it may not be possible to remove the fungus from the soil” because research shows that even when spores are identified in one area one year, they may appear in another location the next.
D’Assumpcao emphasized that as experts continue studying Valley Fever, it becomes increasingly clear that the fungi shift and spread due to environmental cycles and wind patterns.
“It’s a moving target,” he said. “And although some have suggested spraying something to get rid of the fungus, the problem is that the medications—both the ones we give patients and the fungicides sprayed on plants—don’t eliminate them, even though they’re applied all the time.”
He added, “We theorize that these fungicides may actually influence how sensitive Valley Fever is, and could even create resistance to the medications we give people. The other issue is that while developed land may have less fungus in the soil, the surrounding desert areas contribute spores that can travel up to 75 kilometers in windy, post-drought conditions. So even if your soil doesn’t have it, the soil around the Central Valley and in the mountains still can.”
The Central Valley produces about a quarter of the food consumed in the U.S., with 40 percent of the nation’s fruits, vegetables, and nuts coming from this region. D’Assumpcao recognizes the region’s agricultural richness and notes that changing the soil is “not feasible”—not only would it alter the environment, but also the entire ecology of the Central Valley.
Although some individuals may experience severe illness, many show mild or no symptoms after exposure to Valley Fever. Anyone can be at risk—whether living, working, traveling, going to school, or simply stepping outside in the San Joaquin Valley.
D’Assumpcao explained: “Out of 100 people exposed to Valley Fever, about 90 percent will either have no illness or such mild illness that they never see a doctor. Months or years later, we may find evidence in tests that they were exposed, but their bodies were able to overcome the infection. The other 10 percent will need antifungal medication—not to kill the fungus, but to slow it down and give the immune system time to fight it off.”
Research conducted by the UC Davis Department of Public Health in 2020 found that farm laborers who pick and harvest crops, or operate machinery, are at greater risk of contracting Valley Fever due to higher dust exposure.
To reduce risk, D’Assumpcao advised farmworkers and residents of the Central Valley to wear masks, maintain car air filters, and stay indoors during high winds and dust storms whenever possible.
Individuals who may have been exposed should watch for symptoms such as a persistent cough lasting more than three weeks, fatigue, night sweats, fever, or joint pain. Still, D’Assumpcao cautioned that “there is no unifying collection of symptoms because of how differently people respond to the fungus.”
The Valley Fever Institute at Kern Medical also offers a monthly virtual support group, held on the second Wednesday of each month through December 12, welcoming patients, family members, and friends impacted by Valley Fever.
Despite ongoing challenges, the Valley Fever Institute continues its research and patient support work without major disruptions, even as broader conversations about federal funding and medical research cuts raise concerns for the future.
