Coccidioides immitis

From MicrobeWiki, the student-edited microbiology resource

A Microbial Biorealm page on the genus Coccidioides immitis

Sputum culture of Coccidioides immitis on Sabouraud's medium, showing white, cottony fungus growth.


Higher order taxa(1)

cellular organisms; Eukaryota; Fungi/Metazoa group; Fungi; Dikarya; Ascomycota; Pezizomycotina; Eurotiomycetes; Eurotiomycetidae; Onygenales; mitosporic Onygenales; Coccidioides


NCBI: Taxonomy

Coccidioides immitis

Spherule and endospore forms of Coccidioides immitis.Content Providers(s): CDC/Dr. Edwin P. Ewing, Jr. Creation Date: 1989

Description and significance

Coccidioides immitis is a dimorphic fungus (existing in two distinct forms) with a unique life cycle. In the soil, the organism exists as a mold with septated hyphae resembling a shape of a barrel. When entering a host, the arthroconidia (spores) break off from the hyphae and evolve into globular structures called spherules. Then when inside the host, spherules enlarge and undergo internal division, forming smaller structures called endospores. Large spherules can rupture to release packets of endospores, resulting in new foci of infection within the host (2). C. immitis main habitat is in soil, geographically limited to California's San Joaquin valley region, and in the desert southwest and Mexico, where it co exists with its closest relative, Coccidioides posadasii. Formal description of C. immitis was performed by Rixford and Gilchrist from a case observed in California in 1986 (3). However, the parasite was then still thought to be a protozoan. The correct taxonomic status of C. immitis as an ascomycete fungus was demonstrated by Ophuls and Moffit in 1900 (4) by culture on artificial of the fungal mycelia using arthrospores isolated from laboratory infections of guinea pigs. It is important to have its genome sequences because Coccidioides immitis, along with its relative Coccidioides posadasii, can cause a disease called Coccidioidomycosis (Valley Fever), and it is a rare cause of meningitis, mostly in immunocompromised persons, and the disease can be fatal. Persons afflicted with HIV/AIDS are highly susceptible to Coccidioidomycosis and suffer a high mortality rate from the disease. (5).

Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.


Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.


How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required


[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Rachel Larsen