Histoplasma
| Histoplasma | |
|---|---|
 |
|
| Histoplasma (bright red, small, circular). PAS diastase stain | |
| Scientific classification | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Eurotiomycetes |
| Order: | Onygenales |
| Family: | Ajellomycetaceae |
| Genus: |
Histoplasma Darling (1906) |
| Type species | |
|
Histoplasma capsulatum Darling (1906) |
|
| Species | |
Histoplasma capsulatum
Histoplasma duboisii
Histoplasma is a genus of dimorphic fungi commonly found in guano (the feces of birds and bats) and in soil where guano falls. In modern taxonomy, the genus contains a single species, Histoplasma capsulatum, that has several infraspecific varieties. The normal variety is the causative agent of classic histoplasmosis;Histoplasma capsulatum var. duboisii causes African histoplasmosis; and Histoplasma capsulatum var. farciminosum causes epizootic lymphangitis in horses. The duboisii and farciminosum varieties have each formerly been classified as separate species, Histoplasma duboisii and Histoplasma farciminosum.
Histoplasma capsulatum is "distributed worldwide, except in Antarctica, but most often associated with river valleys" and occurs chiefly in the "central and eastern United States" followed by "Central and South America, and other areas of the world" It is most prevalent in the Ohio and Mississippi river valleys. It was discovered by Samuel Taylor Darling in 1906.
Histoplasma capsulatum is an ascomycetous fungus closely related to Blastomyces dermatitidis. It is potentially sexual, and its sexual state, Ajellomyces capsulatus, can readily be produced in culture, though it has not been directly observed in nature. As mentioned above, H. capsulatum groups with B. dermatitidis and the South American pathogen Paracoccidioides brasiliensis in the recently recognized fungal family Ajellomycetaceae. It is dimorphic and switches from a mould-like (filamentous) growth form in the natural habitat to a small budding yeast form in the warm-blooded animal host.
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Wikipedia