Histoplasma capsulatum

Ciri dan struktur

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. 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. Like B. dermatitidis, H. capsulatum has two mating types, "+" and "–". The great majority of North American isolates belongs to a single genetic type, but a study of multiple genes suggests a recombining, sexual population. A recent analysis has suggested that the prevalent North American genetic type and a less common type should be considered separate phylogenetic species, distinct from H. capsulatum isolates obtained in Central and South America and other parts of the world. These entities are temporarily designated NAm1 (the rare type, which includes a famous experimental isolate designated "the Downs strain") and NAm2 (the common type). As yet, no well-established clinical or geographic distinction is seen between these two genetic groups. In its asexual form, the fungus grows as a colonial microfungus strongly similar in macromorphology to B. dermatitidis. A microscopic examination shows a marked distinction: H. capsulatum produces two types of conidia, globose macroconidia, 8–15 μm, with distinctive tuberculate or finger-like cell wall ornamentation, and ovoid microconidia, 2–4 μm, which appear smooth or finely roughened.

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Rujukan: [1]

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Habitat dan peran ekologis

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. The enzootic and endemic zones of H. capsulatum can be roughly divided into core areas, where the fungus occurs widely in soil or on vegetation contaminated by bird droppings or equivalent organic inputs, and peripheral areas, where the fungus occurs relatively rarely in association with soil, but is still found abundantly in heavy accumulations of bat or bird guano in enclosed spaces such as caves, buildings, and hollow trees. The principal core area for this species includes the valleys of the Mississippi, Ohio, and Potomac Rivers in the USA, as well as a wide span of adjacent areas extending from Kansas, Illinois, Indiana, and Ohio in the north to Mississippi, Louisiana, and Texas in the south. In some areas, such as Kansas City, skin testing with the histoplasmin antigen preparation shows that 80–90% of the resident population have an antibody reaction to H. capsulatum, probably indicating prior subclinical infection.

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Rujukan: [1]

Habitat atau konteks temuan

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Substrat

tanah

Peran atau konteks

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Reproduksi

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. 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. Like B. dermatitidis, H. capsulatum has two mating types, "+" and "–". The great majority of North American isolates belongs to a single genetic type, but a study of multiple genes suggests a recombining, sexual population.

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Rujukan: [1]

Catatan identitas dan cakupan

• Nama diterima mengikuti Catalogue of Life Base2026-09-11; uraian mempertahankan konsep dan nama sumber aslinya.
• Original geographic, specimen and life-cycle scope retained; source import awaits individual editorial review.
• Impor dan terjemahan otomatis belum diperiksa editorial per profil. Struktur reproduktif yang disebutkan tidak membuktikan seluruh siklus hidup diketahui.
• Pengukuran pada uraian mengikuti spesimen, kultur, dan metode sumber; angka tidak diperluas ke semua populasi.

Melihat dengan konteks

Dokumentasi Histoplasma capsulatum dari Wikimedia Commons. Histopathology of Histoplasma capsulatum, H&E stain, from a small intestinal granuloma. It shows organisms surrounded by halos, in a granuloma of epithelioid histiocytes. Identifikasi mengikuti record berkas sumber.

Jenis

Fotografi

Kredit

Mikael Häggström , M.D. Author info - Reusing images - Conflicts of interest: None Mikael Häggström , M.D. Consent note : Consent from the patient or patient's relatives is regarded as redundant, because of absence of identifiable features ( List of HIPAA identifiers ) in the media and case information ( See also HIPAA case reports guidance ).

Lisensi

CC BY 4.0

Sumber media

Buka entri sumber

Gambar menunjukkan objek menurut identifikasi sumber, bukan verifikasi independen spesimen oleh Fungi. Tidak ada skala baru yang ditambahkan.

Sumber profil

1. [1] Histoplasma capsulatum — Wikipedia (en)Bagian sumber: Frozen revision 1378916907
   Tanggal penghimpunan sumber: 2026-10-12
   Teks sumber: CC BY-SA4.0 · Wikipedia contributors
2. [2] Catalogue of Life Base2026-09-11 — Histoplasma capsulatumBagian sumber: ColDP NameUsage.tsv ID 3M5JC; accepted species; source 2073
   Tanggal penghimpunan sumber: 2026-10-12
3. [3] Dokumentasi visual — Histoplasma capsulatumBagian sumber: Individual media record; identification follows the source, not independent determination
   Tanggal penghimpunan sumber: 2026-10-12
   Media sumber: CC BY 4.0 · Mikael Häggström , M.D. Author info - Reusing images - Conflicts of interest: None Mikael Häggström , M.D. Consent note : Consent from the patient or patient's relatives is regarded as redundant, because of absence of identifiable features ( List of HIPAA identifiers ) in the media and case information ( See also HIPAA case reports guidance ).