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Learn About Coccidioidomycosis

Coccidioidomycosis, also called valley fever, is a common infection in the southwestern United States that primarily affects the lungs.

Key Facts

  • Coccidioidomycosis is a fungal infection that typically affects the lungs.
  • You get the disease by inhaling fungal spores that are present in the soil.
  • It is not contagious, meaning it cannot be passed from person to person.
  • It may be treated with antifungal medication, but not with antibiotics.

What Is Coccidioidomycosis?

Coccidioidomycosis, commonly referred to as "valley fever," is an infection caused by a fungus (Coccidioides) found in the soil in the southwestern United States, northern Mexico and parts of Central and South America. It is a common cause of pneumonia in Arizona and California but is also present in parts of Utah, Nevada, Texas, and New Mexico. Individuals who either live in or travel through these areas are at risk for infection.

How Coccidioidomycosis Affects Your Body

Once inhaled, the fungus multiplies, leading to the progression and development of the disease. The time from exposure to the development of symptoms may take several weeks. Because the fungus is inhaled, the disease typically affects the lung. In a small number of people, it may spread outside of the lung and affect other parts of the body.

How Serious Is Coccidioidomycosis?

The disease is a common problem in Arizona and California and is being diagnosed more frequently. Since the disease may also occur in travelers to these regions, it has been recognized throughout the country, with more than 100,000 cases being reported nationally between 1998 and 2011. Many more mild cases remain unreported because people with mild symptoms never seek medical attention.

  • Many people who have coccidioidomycosis have minimal symptoms and do not require treatment.
  • Some people may develop a more serious disease that requires treatment.
  • More serious or progressive disease may develop in anyone, but people with weakened immune systems are at higher risk.

    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.

    Last updated April 4, 2018.

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