Figure 1.

Life cycle of Coccidioides spp.

Notes: In the environment Coccidioides exists as a mycelium and following periods of low precipitation arthroconidia are formed and are easily aerosolized when disturbed. Arthroconidia can be inhaled or return to the soil and again grow to vegetative mycelia. However if inhaled, arthroconidia undergo a morphologic change and become immature spherules which divide internally until filled with endospores and subsequently rupture. Endospores are dispersed into the surrounding tissue and are then able to form new spherules and repeat the cycle.