Coccidioidomycosis (Valley Fever)
A fungal lung infection from breathing in desert soil spores
Quick Facts
- Type: Fungal infection
- Also called: Valley fever
- Source: Spores in dry soil of the southwestern US
- Mainly affects: Lungs
Overview
Coccidioidomycosis, commonly known as valley fever, is an infection caused by the Coccidioides fungus, which lives in the dry, dusty soil of certain regions. People become infected by breathing in fungal spores that become airborne when soil is disturbed by wind, digging, or construction. It does not spread from person to person.
The infection mainly affects the lungs and often causes a flu-like or pneumonia-like illness. Many people have mild symptoms or none at all and recover on their own, but some develop more serious or long-lasting disease, and in a small number the infection spreads beyond the lungs. Valley fever is most common in the southwestern United States, parts of Mexico, and Central and South America, where the fungus thrives in the dry soil.
Symptoms
Symptoms usually appear one to three weeks after exposure and can resemble the flu or pneumonia.
- Fatigue and feeling generally unwell
- Cough and chest pain
- Fever, chills, and night sweats
- Shortness of breath
- Headache
- Muscle and joint aches
- A rash, sometimes with tender red bumps on the lower legs
Most people recover, but symptoms can linger for weeks. Severe breathing difficulty, or signs that the infection has spread such as severe headache, neck stiffness, or new bone and joint pain, need prompt medical attention.
Causes
Valley fever is caused by inhaling spores of the Coccidioides fungus.
- Environmental source: The fungus lives in dry desert soil in specific regions.
- Airborne spores: When soil is disturbed by wind, dust storms, digging, farming, or construction, spores rise into the air and can be inhaled.
- How infection starts: Inhaled spores can grow in the lungs and trigger infection.
The infection is not passed between people; it comes only from the environment.
Risk Factors
- Living in or traveling to regions where the fungus is common, such as the southwestern United States, especially Arizona and parts of California
- Outdoor and soil-disturbing work such as farming, construction, and archaeology
- Exposure to dust storms
- A weakened immune system, which raises the risk of severe or spreading infection
- Pregnancy and certain ethnic backgrounds, which can increase the risk of severe disease
Diagnosis
Because valley fever resembles other lung infections, specific tests are often needed:
- Blood tests: Looking for antibodies the body makes against the fungus.
- Imaging: Chest X-rays or CT scans to assess the lungs.
- Laboratory study of samples: Examining and culturing sputum or tissue to identify the fungus.
Telling your doctor about travel to or residence in regions where valley fever occurs helps guide testing and diagnosis.
Treatment
Treatment depends on the severity of illness and the person's risk.
- Mild cases: Many healthy people recover without antifungal medication, with rest and supportive care, while the doctor monitors them.
- More significant or persistent disease: Oral antifungal medication, sometimes for months.
- Severe or spreading infection: Stronger intravenous antifungal treatment and specialist care, especially if it reaches the brain, bones, or other organs.
- High-risk people: Those with weakened immune systems may need longer treatment and closer follow-up.
Most people recover fully, though fatigue can persist for a while during recovery.
Prevention
There is no vaccine, and the fungus cannot be fully avoided in regions where it lives, but some measures may reduce exposure, especially for higher-risk people:
- Avoid heavy dust exposure and stay indoors during dust storms when possible
- Wet down soil before digging and consider a well-fitted mask during dusty work
- Keep car windows closed and use recirculated air when driving through dusty areas
- If you are at higher risk, discuss precautions with your doctor before activities that stir up soil
When to See a Doctor
See a doctor if you have a cough, fever, fatigue, chest pain, or flu-like symptoms that last more than a week or do not improve, especially after spending time in regions where valley fever occurs.
Seek urgent care for severe shortness of breath, a severe or worsening headache with neck stiffness, confusion, new bone or joint pain, or rapidly worsening symptoms, particularly if you have a weakened immune system, as these may signal spreading infection.
Frequently Asked Questions
What is valley fever?
Valley fever is the common name for coccidioidomycosis, a fungal infection caused by breathing in spores of the Coccidioides fungus from dry desert soil. It mainly affects the lungs and often causes flu-like or pneumonia-like symptoms.
Is coccidioidomycosis contagious?
No. It does not spread from person to person. People become infected only by inhaling fungal spores from the environment, usually when soil is disturbed by wind or digging.
Where do people get valley fever?
It is most common in the southwestern United States, especially Arizona and parts of California, as well as parts of Mexico and Central and South America. Travel to or living in these areas raises the risk of exposure.
Does valley fever always need treatment?
No. Many healthy people recover on their own with rest while a doctor monitors them. Antifungal medication is used for more significant, persistent, or severe disease, and for people at higher risk such as those with weakened immune systems.
When is valley fever serious?
It can become serious if it spreads beyond the lungs to the brain, bones, or other organs, which is more likely in people with weakened immune systems. Seek urgent care for severe headache with neck stiffness, confusion, severe breathing trouble, or new bone and joint pain.
References
- Centers for Disease Control and Prevention (CDC). Valley Fever (Coccidioidomycosis).
- MedlinePlus, U.S. National Library of Medicine. Coccidioidomycosis.
- Mayo Clinic. Valley fever.
- National Institute of Allergy and Infectious Diseases (NIAID). Fungal diseases.