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American public health officials are becoming more and more concerned about a potentially fatal disease that is spreading across the western United States from the Central Valley of California as far east as Texas. Known colloquially as valley fever and in the medical literature as coccidioidomycosis, this fungal infection has become an epidemic in Arizona and California, but remains virtually unheard of in the rest of the country. The dust-borne fungus, however, can strike visitors to the American West as well as travelers.
What Is Coccidioidomycosis?
The nearly-unpronounceable fungal infection is caused by two species of fungus, Coccidioides immitis and Coccidioides posadaii. These fungi live in dry, alkaline soils at lower elevations in interior California and Texas, and in Arizona, Utah, New Mexico, and most of the states of northern Mexico. They are also found in some locations in Central and South America.
The fungus grows long filaments in the dirt during the local rainy season. When the soil dries out, the fungus catches a ride with dust particles and finds its way into the lungs of passersby. In 60 to 65% of cases, the fungus causes symptoms so mild that they go unnoticed. In the other 35 to 40% of infections, the fungus causes relatively mild, flu-like symptoms. The fever, muscle aches, joint pain, severe cough, and pain when breathing start about about a week after exposure and last about a month.
In about 1 in 150 cases, however, the fungus escapes the lungs and infects other parts of the body. The fungus prefers the lungs, soft tissues, joints, and meninges lining the nerves and brain, in these especially severe cases causing meningitis. The fungus may also cause mild to severe fungal pneumonia, urinary tract problems, and kidney or (in men) prostate infections. In women, the fungus may cause cervical infections and cell abnormalities that are detectible on the Pap smear. The coccidioidomycosis infection, however, can strike any organ in the body.
Who Gets Coccidioidomycosis?
Every year about 150,000 people come down with symptoms of this fungal infection, but only about 25,000 are diagnosed as valley fever, California fever, San Joaquin Valley fever, or desert rheumatism. At one time the disease was common only at lower elevations around Phoenix, Arizona and Fresno, California, with booming population the condition is increasing common throughout the American West. About 80% of people who live in the West have antibodies to the disease. And every year about 100 people die from the disease.