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What is Valley Fever?


Updated September 20, 2011

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.


Valley fever - also called coccidioidomycosis - is a fungal infection that occurs mainly in people living in the Southwestern United States, parts of Mexico and South America. Because the fungus lives in the soil, it affects people who are frequently exposed to dirt and soil, such as farmers, construction workers and military personnel doing outdoor training.

Valley fever is known by several other names including: cocci, California disease, desert rheumatism and San Joaquin Valley fever.


Symptoms of valley fever vary greatly. Many people who get it experience virtually no symptoms, while others can develop symptoms that last for months. Common symptoms of valley fever (in those who develop symptoms) include:

  • Fever
  • Cough
  • Rash
  • Headache
  • Muscle and/or joint aches

A few people who get valley fever will develop a serious illness. In these people, the spores from the fungus that cause the infection travel deep into the lungs, where they grow and develop into pods. The pods eventually burst, releasing tiny seeds into the lungs and sometimes to other parts of the body. Inflammation occurs in the areas where the seeds settle.


Valley fever is caused by the fungus species Coccidioides immitis. This fungus lives in the soil of dry places such as the deserts of the Southwest.

Who Is Affected:

Anyone can get valley fever, but it most commonly occurs in people who are frequently exposed to soil and dust, such as those who work outside.

Valley fever is not contagious - meaning it cannot be passed from person to person.

If you have been infected with the fungus that causes valley fever, your body will develop an immunity to it. Repeat infections almost never occur.

Diagnosis and Treatment:

If your healthcare provider believes you could have valley fever, there are a number of different tests that he or she could order. It can be diagnosed by:

  • Blood test
  • Skin test
  • Chest X-ray
  • Examining the sputum to check for the presence of the cocci fungus

Valley fever typically resolves on it's own within a few weeks. In some cases, your healthcare provider may decide to treat the infection with antifungal medications.

Rarely, surgery may be necessary to remove infected portions of the lungs, bone or skin.

Possible Complications:

On rare occasions, a person may develop a serious infection due to valley fever. It can result in chronic lung infections or widespread fungal infections throughout the body.

Those at highest risk for complications are people who have weakened immune systems, those of African-American, Filipino or Asian descent and pregnant women in their third trimester. Serious infections may require hospitalization or surgery.

Preventing Valley Fever:

Although some people are more likely to get valley fever than others, it can occur in anyone who lives in or visits an area where the Coccidioides immitis fungus is present.

If you work outdoors in areas where this disease is common and are at high risk for developing complications, you may want to wear a mask to cut down on your chances of inhaling the spores.

If possible, avoid dust storms, especially if you are at risk for more serious disease. Blowing dust stirs up the spores, increasing the chance that you could inhale them.

If you live in or have visited a location where valley fever is common, pay attention to your symptoms. If you develop flu-like symptoms, contact your healthcare provider and let him or her know you are concerned about valley fever. Symptoms typically appear between one and three weeks after exposure to the fungus.


"Valley Fever." Medline Plus 01 Sep 11. US National Library of Medicine. 15 Sep 11.

"Coccidioidomycosis (Cocci)." American Lung Association 2011.

"Coccidioidomycosis." National Center for Emerging and Zoonotic Infectious Diseases 20 Jul 10. US Centers for Disease Control and Prevention. 18 Sep 11.

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