BAKERSFIELD, Calif. — In 36 years with the Los Angeles police, Sgt. Irwin Klorman faced many dangerous situations, including one routine call that ended with Uzi fire and a bullet-riddled body sprawled on the living room floor.

But his most life-threatening encounter has been with coccidioidomycosis, or valley fever, for which he is being treated here. Coccidioidomycosis, known as “cocci,” is an insidious airborne fungal disease in which microscopic spores in the soil take flight on the wind or even a mild breeze to lodge in the moist habitat of the lungs and, in the most extreme instances, spread to the bones, the skin, the eyes or, in Mr. Klorman’s case, the brain.

The infection, which the Centers for Disease Control and Prevention has labeled “a silent epidemic,” is striking more people each year, with more than 20,000 reported cases annually throughout the Southwest, especially in California and Arizona. Although most people exposed to the fungus do not fall ill, about 160 die from it each year, with thousands more facing years of disability and surgery. About 9 percent of those infected will contract pneumonia and 1 percent will experience serious complications beyond the lungs.