Coccidioidomycosis is a fungal infection (caused by a fungus). The fungus is endemic in soils of the southwest region of the United States (California, Arizona and Texas) and Mexico (Baja California, Sonora, Nuevo Leon and Coahuila.
Coccidioidomycosis is caused by dimorphic, soil-borne fungi, ascomycetes Coccidioides immitis, and C. posadasii (formerly known as the “California” and “non-California” populations of C. immitis). C. immitis and C. posadasii differ in some characteristics such as tolerance to heat and salt, however, no differences in pathogenicity have been observed.