Coccidioides immitis is a pathogenic fungus that resides in the soil in certain parts of the southwestern United States, northern Mexico, and a few other areas in the Western Hemisphere. Epidemiology C. immitis, along with its relative C. posadasii, is most commonly seen in the desert regions of the southwestern United States, including certain areas of Arizona, California, New Mexico, Nevada, Texas, and Utah; and in Central and South America in Argentina, Brazil, Colombia, Guatemala, Honduras, Mexico, Nicaragua, Paraguay, and Venezuela. Precise location C. immitis is largely found in California, but also Baja California and Arizona, while C. posadasii is regularly found in Texas, northern Mexico and in Central and South America. Both C. immitis and C. posadasii are present in Arizona. C. immitis is more common west of the Tehachapi mountains, while posadasii east of it. Coccidioides spp. are found in alkaline, sandy soils from semi-desert regions with hot summers, gentle winters, and annual rainfall between 10 and 50 cm. These fungi are usually found 10 to 30 cm beneath the surface. Clinical manifestation C. immitis can cause a disease called coccidioidomycosis (valley fever). Its incubation period varies from 7 to 21 days. Coccidioidomycosis is not easily diagnosed on the basis of vital signs and symptoms, which are usually vague and nonspecific. Even a chest X-ray or CT scan cannot reliably distinguish it from other lung diseases, including lung cancer. Blood or urine tests are administered, which aim to discover Coccidioides antigens. However, because the Coccidioides creates a mass that can mimic a lung tumor, the correct diagnosis may require a tissue sample (biopsy). A Gomori methenamine silver stain can then confirm the presence of the Coccidioides organism's characteristic spherules within the tissue. The C. immitis fungus can be cultured from a patient sample, but the culture can take weeks to grow and requires special precautions on a part of the laboratory staff while handling it (screw cap vials and sterile transfer hoods are recommended). It is reported as the tenth-most often acquired infection in the laboratory conditions with two documented deaths. Until October 2012, C. immitis had been listed as a select agent by both the U.S. Department of Health and Human Services and the U.S. Department of Agriculture, and was considered a biosafety level 3 pathogen. Treatment Most Coccidioides infections have an incubation period from one to four weeks and resolve without specific therapy; few clinical trials