You do not have to live in the Valley to catch valley fever. If you work or play in Maricopa, Pima and Pinal counties - where most of Arizona's valley fever occurs - you could be exposed to the fungus that causes the infection. Construction, road and agricultural workers as well as ranchers, archeologists and military personnel on field exercises are among those whose work could expose them to the fungus. If you enjoy exploring the desert with ATVs or four-wheel-drive vehicles, you could stir up soil and inhale airborne Coccidioides immitis, the spore that causes valley fever.
Arizona is the hub of valley fever in the United States. Approximately 60 percent of the 150,000 infections reported annually in the U.S. occur in Arizona and more cases are being reported each year. Last year, 16,472 valley fever cases were reported to the Arizona Department of Health Services (ADHS), an increase of more than 4,500 from 2010. The peak season for valley fever is from June through August and October through November.
Who is at greatest risk for developing infection from the coccidioides fungus? Valley fever occurs more frequently in young children, the elderly and those with weakened immune systems. Women in their third trimester of pregnancy also are vulnerable to a more serious form of the fungus. For reasons not well understood, it also occurs more often in African-Americans, Hispanics and Native Americans as well as people of Asian and Filipino descent.
Most people exposed to the coccidioides fungus do not develop valley fever symptoms while some experience mild, flu-like symptoms that eventually go away on their own. The symptoms of a mild case of valley fever include: fever, cough, headache, a rash on the upper trunk or extremities, muscle pains, and joint pains in the knees and ankles. More severe cases of valley fever can include skin lesions, chronic pneumonia, meningitis and bone or joint infections. Symptoms typically surface between one to three weeks after exposure to the fungus and can last six months or longer. The long-term effects of valley fever are rare, but can include damage to the nervous system.
Treatment for this infection is not always necessary. If symptoms persist for longer than a week or you are included in one of the at-risk groups, it's important to seek medical treatment as soon as possible. In these cases, your doctor may prescribe an antifungal medication.
If you are visiting a valley fever-prone area during a peak month, it is best to avoid areas with large amounts of dust in the air, or to wear a mask as a way to limit dust exposure. Also, clean any skin injuries that have been exposed to soil or dust as you can be exposed to the valley fever fungus through an open wound or abrasion. Other precautions include wetting the soil if you are going to dig and keeping doors and windows closed.