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Valley Fever - still a mystery
An estimated 50,000 to 100,000 persons develop symptoms of Valley Fever each year in the United States, with 35,000 new infections per year in California alone. In Arizona, the incidence of reported cases was 15 per 100,000 in 1995.

Valley Fever (or San Joaquin Valley Fever) is a disease of the lungs that is common in the southwestern United States (California, Arizona, West Texas, New Mexico), northwestern Mexico, Central and South America. It is caused by the fungus “coccidioides immitis,” which grows in soils in areas of low rainfall, high summer temperatures and moderate winter temperatures.

These spores become airborne when the soil is disturbed by winds, construction, farming or earthquakes. The tiny seeds, or spores, become wind-borne and are inhaled into the lungs, where the infection starts. Once in the lung, the spore changes into a multicellular structure called a spherule, which grows and bursts. Valley Fever symptoms generally occur within three weeks of exposure. Valley Fever is not a “contagious” disease, meaning it is not passed from person to person. Once a person is infected, a second infection is rare. Sometimes, a small thin walled cavity may be formed in the lung from the infection, and half of these patients have a stubborn cough, often coughing up small amounts of blood.

Who gets Valley Fever?
Anyone who lives, visits or travels through the areas where the fungus grows in the soil may get Valley Fever. Truckers who constantly pick up produce loads in California’s central valley are at risk. People working in occupations such as farming, construction, excavation, oil production, archaeological digging and other occupations, which disturb soil in areas where the disease is known to occur, may be at increased risk. People who hike, bike or driving ATVs or 4-wheel drive vehicles in the desert may also be at increased risk. Various domestic animals such as dogs and horses as well as wild animals are also susceptible. The earthquakes that occurred in the 1990s in California have also resulted in increased cases of Valley Fever.

Most cases of Valley Fever are very mild. Reportedly, more than 60 percent of infected people have either no symptoms or experience flu-like symptoms and never seek medical attention. Of those patients seeking medical care, the most common symptoms are fatigue, cough, chest pain, fever, rash, headache and joint aches. The changes in bones and joints due to Valley Fever infection can be seen on X-rays and in CT-scans of the affected body part. Some people develop painful red bumps on their shins or elsewhere that gradually turn brown. Only 1 to 2 percent develop a disease that spreads (disseminates) to other parts of the body. These symptoms, however, are not unique to Valley Fever and can be caused by other illnesses.

Therefore, identifying Valley Fever as the cause of illness requires specific laboratory tests.

Depending upon the symptoms, Valley Fever may be confused with cancer, tuberculosis, chronic obstructive pulmonary disease, chronic fatigue syndrome and others. However, if the specific blood test to measure antibodies against the fungus is performed along with chest X-rays, travel history through the Southwest, and when appropriate skin test results are performed and considered, a diagnosis is made.

Usually, the body’s immune response is effective and no specific course of treatment is necessary, but Valley Fever continues to take its toll. There is no vaccine against Valley Fever at the present time, but in Bakersfield, CA, the Valley Fever Research Foundation continues to work toward the development of a vaccine. So for now, persons at risk should avoid exposure to dust and dry soil in areas where Valley Fever is common.

Source: Biomedical Research Foundation of Southern Arizona