Valley Fever Comes From Fungal Spores, Often Misdiagnosed
The U.S. Centers for Disease Control and Prevention (CDC) says Valley fever (coccidioidomycosis) is a lung infection caused by breathing in spores from a fungus called Coccidioides, which lives in soil in some areas of the southwestern U.S. and south-central Washington state. CDC also says that because Valley fever has the same symptoms as pneumonias caused by bacteria or viruses, it is often misdiagnosed or undiagnosed, delaying treatment when needed; if your symptoms last for more than a week, contact your healthcare provider.
CDC says people who get sick with Valley fever usually get better on their own, but some people will need antifungal medication, and early treatment with antifungal medications can save lives. Valley fever does not spread from person to person or between people and animals. This article follows CDC's Valley fever overview, risk reduction and symptoms pages: symptoms, who is more likely to get severely ill, and how to reduce breathing in spores. Everyone's health is different; if you have questions, ask your health care provider.
What Valley fever is
CDC explains (CDC, About Valley Fever):
- Where it is: The fungus is found in soil in the Pacific Northwest and southwestern United States, and parts of Mexico, Central America and South America.
- How people get it: By breathing in the spores; some people breathe in the spores and never get sick.
- Pets: Cats and dogs can also get infected, but it does not spread to people.
- Severe illness: About 5 to 10% of people who get Valley fever develop serious or long-term lung problems; an even smaller share (about 1%) have the infection spread from the lungs to other parts of the body, such as skin, bones, joints or the brain (meningitis).
- Treatment: Usually people get better on their own within weeks or months without treatment; some need treatment to reduce symptoms or stop them from getting worse; severe or spreading infections require antifungal medication and may require hospitalization.
- Getting it again: Most people who get Valley fever never get it again; relapses are very rare.
Symptoms
CDC explains (CDC, Symptoms of Valley Fever):
- Common symptoms: Fatigue, cough, fever and headache, shortness of breath, night sweats, muscle aches or joint pain, and rash on the upper body or legs.
- When they appear: Symptoms may appear 1 to 3 weeks after breathing in spores and usually last a few weeks to a few months; some patients have symptoms longer, especially if the infection becomes severe.
- More than a week: If your symptoms last for more than a week, contact your healthcare provider.
- Varies by person: Symptoms differ from person to person.
Who is more likely to get severely ill
CDC explains (CDC, Reducing Risk for Valley Fever): Most of the time, people who breathe in the spores do not get sick, and most who get sick get better on their own. Groups that may be at higher risk for severe illness include:
- People with weakened immune systems: For example, people who have HIV/AIDS, have had an organ transplant, or are taking medications such as corticosteroids or TNF inhibitors.
- Other groups: Pregnant women, people who have diabetes, people who are Black or Filipino, and people over 60.
How to reduce breathing in spores
- No vaccine: No vaccines are available at this time; CDC says it is very difficult to avoid breathing in the fungus in areas where it lives.
- Avoid dusty areas: Avoid areas with a lot of dust, like construction or excavation sites; if that is not possible, wear a fitted N95 respirator.
- Dust storms: Stay inside during dust storms and close your windows.
- Soil: Avoid activities involving contact with soil, like gardening.
- Indoors: Use air filtration indoors.
- Wounds: Clean skin injuries well with soap and water to prevent infection.
- People at higher risk: Healthcare providers may prescribe antifungal medications to prevent infection in people at increased risk because of health conditions.
- Exposure at work: Workers who think they were exposed at work should report to their occupational health or risk management department; if there is none, contact the local health department; anyone who develops symptoms should see a healthcare provider for testing.
For checking AirNow when air quality is poor, see AQI Over 100 Means Sensitive Groups Take Care, Check AirNow; for where to see a doctor when you are sick, see ERs Can't Refuse the Uninsured, Ask for Self-Pay Estimates.
What this article did not check
- Exact areas: CDC has a separate page on areas; this article did not check states or counties.
- Testing and treatment: Ask your healthcare provider; this article does not cover them.
- Workplace rules: CDC has separate workplace safety material; this article did not check it.
FAQ
Can Valley fever spread to my family?
No. CDC says Valley fever does not spread from person to person or between people and animals.
How long should a cough and fever last before I see a doctor?
CDC says that if your symptoms last for more than a week, contact your healthcare provider.
Is there a vaccine?
No. CDC says no vaccine to prevent Valley fever is available at this time.
How can I lower my risk if I live where it is common?
CDC says to avoid dusty areas like construction sites, or wear a fitted N95 respirator if you can't; stay inside and close windows during dust storms; avoid soil activities like gardening; and use air filtration indoors.
Sources and date checked
All checked on 2026-11-02.
- CDC, About Valley Fever (page dated 2024-04-24):https://www.cdc.gov/valley-fever/about/index.html
- CDC, Symptoms of Valley Fever (page dated 2024-04-24):https://www.cdc.gov/valley-fever/signs-symptoms/index.html
- CDC, Reducing Risk for Valley Fever (page dated 2024-04-24):https://www.cdc.gov/valley-fever/prevention/index.html