Coccidioides posadasii
Encyclopedia
Coccidioides posadasii is a pathogen
ic fungus
that, along with Coccidioides immitis
, is the causative agent of coccidioidomycosis
("valley fever") in human
s. It resides in the soil
in certain parts of the Southwestern
United States
, northern Mexico
, and certain other areas in the Americas
.
C. posadasii and C. immitis are morphologically identical but genetically and epidemiologically distinct. C. posadasii was identified as a separate species than C. immitis in 2002. The two species can be distinguished only by genetic analysis and different rates of growth in the presence of high salt concentrations (C. posadasii grows more slowly). It is also found outside the San Joaquin Valley
, unlike its relative; while C. immitis is geographically limited to the valley, C. posadasii can also be found in the desert southwest of Mexico and South America
.
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
ic fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
that, along with Coccidioides immitis
Coccidioides immitis
Coccidioides immitis is a pathogenic fungus that resides in the soil in certain parts of the southwestern United States, northern Mexico, and a few other areas in the Western Hemisphere....
, is the causative agent of coccidioidomycosis
Coccidioidomycosis
Coccidioidomycosis is a fungal disease caused by Coccidioides immitis or C. posadasii. It is endemic in certain parts of Arizona, California, Nevada, New Mexico, Texas, Utah and northwestern Mexico.C...
("valley fever") in human
Human
Humans are the only living species in the Homo genus...
s. It resides in the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
in certain parts of the Southwestern
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...
United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, and certain other areas in the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
.
C. posadasii and C. immitis are morphologically identical but genetically and epidemiologically distinct. C. posadasii was identified as a separate species than C. immitis in 2002. The two species can be distinguished only by genetic analysis and different rates of growth in the presence of high salt concentrations (C. posadasii grows more slowly). It is also found outside the San Joaquin Valley
San Joaquin Valley
The San Joaquin Valley is the area of the Central Valley of California that lies south of the Sacramento – San Joaquin River Delta in Stockton...
, unlike its relative; while C. immitis is geographically limited to the valley, C. posadasii can also be found in the desert southwest of Mexico and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.