Coccidioides posadasii (C. posadasii)

Coccidioides posadasii is a dimorphic pathogenic fungus and one of the two primary causative agents of coccidioidomycosis, also known as Valley Fever (Fisher et al., 2002). It is geographically widespread, found in arid regions of the Southwestern United States (outside of California), Mexico, and Central and South America (CDC, 2023). The organism exists in a saprobic phase as filamentous mold in the soil and transitions to a parasitic phase characterized by the formation of spherules and endospores upon inhalation by a host (StatPearls, 2024). This transition is critical for its pathogenicity and survival within the human respiratory system. Clinical manifestations range from asymptomatic or mild respiratory illness to severe, disseminated disease affecting the meninges, bones, and skin (Mayo Clinic, 2023). Pharmacological intervention typically involves antifungal agents that target fungal-specific pathways, such as ergosterol biosynthesis in the cell membrane or chitin synthesis in the cell wall (NIH, 2023). Management of the infection is often prolonged, and the choice of therapy depends on the severity and location of the disease.

Other names

Valley Fever fungusNon-California CoccidioidesCoccidioides immitis non-California population

Inhibition of lanosterol 14-alpha-demethylase (CYP51), disruption of fungal cell membrane integrity via ergosterol binding, and inhibition of chitin synthase.