Infectious Diseases
Valley Fever
Backed by more than 50 years of experience, the UC Davis Center for Valley Fever offers expert diagnosis and treatments for this fungal infection.
Medically reviewed by Dean Blumberg, M.D. on Aug. 20, 2025.
What Is Valley Fever?
Valley fever is a type of fungal infection that occurs when you breathe in Coccidioides spores in the air. This fungus lives in soil in California, the Pacific Northwest, and southwestern states. Disturbing the soil can make the fungus airborne. Valley fever is also called coccidioidomycosis or cocci.
Most people exposed to the fungus don’t get sick. But up to 1 in 10 people develop serious, long-term lung problems. Less commonly, the fungal infection can spread to other parts of your body and become life-threatening.
Cases of Valley fever are on the rise in California and other states. Infectious disease specialists at the UC Davis Center for Valley Fever treat this fungal infection with expert knowledge and care, helping to improve your health and quality of life. Our Coccidioidomycosis Serology Laboratory has more than 50 years of experience testing for and confirming Valley fever cases.
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Symptoms of Valley Fever
Valley fever doesn’t always cause symptoms. When symptoms occur, they typically appear one to three weeks after exposure. You may have symptoms similar to the flu or COVID-19, which last for a few weeks or months. The infection can worsen and spread through your body, so it’s important to seek medical care for Valley fever symptoms.
Common Symptoms
Common signs of Valley fever include:
- Chest pain
- Cough
- Fatigue
- Fever
- Headaches
- Muscle aches or joint pain
- Night sweats
- Rash on your legs or upper body
- Shortness of breath
- Unintentional weight loss
Emergency Symptoms
Disseminated Valley fever occurs when the infection spreads to your bones, joints, or skin. It can also affect your brain, causing coccidioidal meningitis. Disseminated Valley fever can be life-threatening. You should seek immediate medical care if you or a loved one has these symptoms:
- Confusion or behavioral changes
- Difficulty remembering, thinking, or concentrating
- Double or blurry vision
- Muscle weakness or difficulty moving
- Neck pain or stiffness
- Persistent nausea and vomiting
- Ringing in your ears (tinnitus)
Causes and Risk Factors for Valley Fever
You get Valley fever from breathing in spores of the Coccidioides fungus. These spores can become airborne when dust kicks up. You may be exposed while living in or visiting areas where the fungus is present. These areas include California’s Central Valley, Pacific Northwest, southwestern United States, and parts of Mexico, Central America, and South America. Valley fever isn’t spread from person-to-person.
Certain factors increase your risk of getting Valley fever, including:
Age, Ethnicity and Race
People who are older than 60, Black, or Filipino are most at risk.
Diabetes
People with diabetes are at risk for all types of fungal infections. Having diabetes also increases your risk of developing a severe respiratory (lung) infection if you get Valley fever.
Jobs or Hobbies
People who work in soil, such as farmers, gardeners, landscapers, and construction workers, are more likely to be exposed to the fungus. You may also be exposed during outdoor activities like hiking or biking.
Pregnancy
People who are in their third trimester of pregnancy are more likely to get Valley fever.
Weak Immune System
Having a weakened immune system due to medical conditions or treatments increases risk.
Diagnosis and Testing for Valley Fever
Our Coccidioidomycosis Serology Laboratory has been testing patients for Valley fever for more than 50 years. This deep expertise helps you get an accurate diagnosis quickly.
Blood Test
A coccidioidal or cocci serology blood test is the best way to diagnose Valley fever. This test measures the level of antibodies (titers) to the fungus in your blood.
Sputum Culture
A sputum culture checks mucus you cough up (phlegm or sputum) for signs of the fungus.
Imaging Tests
A chest X-ray or other medical imaging can detect a lung infection or other complications, such as disseminated Valley fever.
Valley Fever Treatments
Infectious disease experts at our Center for Valley Fever carefully monitor patients with mild symptoms. We start treatment only when necessary.
Antifungal Medications
Antifungal medications kill the fungus and stop it from growing. You may need to take oral antifungal medicine for three to six months to ease symptoms and prevent the infection from worsening.
Hospitalized Care
People with lung infections or disseminated Valley fever need IV or oral antifungal treatment in a hospital. You may need to continue antifungal medications after you leave the hospital. People who have coccidioidal meningitis may need to take antifungal medications for life.
Preventing Valley Fever
You can’t see fungal spores, and it can be difficult to avoid breathing them in. However, certain actions may help lower your risk.
Wear a Mask
Wearing an N95 respirator mask over your nose and mouth, especially when engaging in activities that stir up dust, offers some protection.
Minimize Dust in Your Home
Keep the windows and doors of your home closed, especially on windy days or during dust storms. Using a home air purifier and high-efficiency particulate air (HEPA) filters may also help.
Take Outdoor Precautions
Reduce your exposure to dust by wetting soil before you start digging and staying upwind from dust.
Reduce Dust in Your Car
If you’re driving in an area where Valley fever is common, keep your car windows closed and recirculate the air.
“About Valley Fever,” Centers for Disease Control and Prevention, https://www.cdc.gov/valley-fever/about/index.html
“Valley Fever,” California Department of Public Health, https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Coccidioidomycosis.aspx
A record high
12,500Valley fever cases were recorded in California in 2024.
About
5-10%Of people with Valley fever develop serious or chronic lung problems.
Sources: California Department of Public Health: Valley Fever Basics
Centers for Disease Control and Prevention: About Valley Fever
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