Coccidioides immitis is a member of the Kingdom, Fungi; Phylum, Ascomycota; Class, Euascomycetes; Order, Onygenales; Family Onygenaceae; and the Genus Coccidioides. Coccidioides immitis are thermally dimorphic fungus that reproduces by arhroconidia, swelling of arhroconidia in vivo into spherules (which burst and release endospores.) The fungi is found mainly in warm dry areas with low rain fall, high summer temperatures, and low altitude. C. immitis is geographically limited to the san Joaquin valley region, and co exists with C. Posadasii in the desert southwest of the United States, Mexico, and South America. C. immitis specifically inhabits alkaline soil and is isolated in rodent burrows at desert like areas of southwest Unites States. It has no known teleomorph. Coccidioides immitis \ C. Posadasii are the only species included in the genus Coccidioides.
Coccidioides immitis causes systemic mycosis beginning as a respiratory infection; primary infection is asymptomatic or flue like. 1/5 of clinical cases develop erythematic nodosum and there is a rare progression to disseminated disease which is more common pregnant women; blacks, and Filipinos. It can become progressive, and causes frequently fatal glaucomatous disease with lung lesions and abscesses throughout the body. It can also cause Meningitis and is 90% fatal if left untreated. Common infections can occur in arid and semiarid areas of the western hemisphere. Dusty fomites from endemic areas can transmit infection elsewhere. It affects all ages, both sexes, and all races; and is common in summer after wind and dust storms.
Coccidioides immitis mode of transmission is mainly due to inhalation of infective arhroconidia from the soil and has a high propensity for airborne transmission and retention in deep pulmonary spaces. Laboratory accidents involving cultures are common. It has and incubation period of 1-4 weeks in primary infection, disseminated infection may develop...
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