Trichophyton

Trichophyton is a genus of fungi, which includes the parasitic varieties that cause tinea, including athlete's foot, ringworm, jock itch, and similar infections of the nail, beard, skin and scalp. Trichophyton fungi are molds characterized by the development of both smooth-walled macro- and microconidia. Macroconidia are mostly borne laterally directly on the hyphae or on short pedicels, and are thin- or thick-walled, clavate to fusiform, and range from 4 to 8 by 8 to 50 μm in size. Macroconidia are few or absent in many species. Microconidia are spherical, pyriform to clavate or of irregular shape, and range from 2 to 3 by 2 to 4 μm in size.
Species and their habitat preference
According to current classification, the genus includes anthropophilic and zoophilic species. Anthropophilic fungi prefer to infect humans. Zoophilic fungi prefer to infect animals other than humans. Humans and animals are natural reservoirs for parasitic or dermatophytic fungi.
Other accepted species;
Trichophyton ajelloi
Trichophyton areolatum
Trichophyton balcaneum
Trichophyton batonrougei
Trichophyton brumptii
Trichophyton candelabrum
Trichophyton cerebriforme
Trichophyton circonvolutum
Trichophyton denticulatum
Trichophyton depressum
Trichophyton farinulentum
Trichophyton fischeri
Trichophyton flavescens
Trichophyton floriforme
Trichophyton fluviomuniense
Trichophyton fuligineum
Trichophyton glabrum
Trichophyton gloriae
Trichophyton gourvilii
Trichophyton guzzonii
Trichophyton immergens
Trichophyton indicum
Trichophyton indotineae
Trichophyton kanei
Trichophyton krajdenii
Trichophyton kuryangei
Trichophyton longifusum
Trichophyton louisianicum
Trichophyton mariatii
Trichophyton megninii
Trichophyton milochevitchii
Trichophyton multicolor
Trichophyton oceanicum
Trichophyton ochoterenai
Trichophyton olexae
Trichophyton pedis
Trichophyton plurizoniforme
Trichophyton pratense
Trichophyton proliferans
Trichophyton pseudotonsurans
Trichophyton purpureum
Trichophyton radicosum
Trichophyton raubitschekii
Trichophyton rotundum
Trichophyton sabouraudii
Trichophyton sarkisovii
Trichophyton spadix
Trichophyton teheraniense
Trichophyton tenuishyphum
Trichophyton vanbreuseghemii
Mating and meiosis
Trichophyton mentagrophytes (Family Arthrodermataceae, Genus Trichophyton) is capable of both mating and meiosis.
Effect on humans
The anthropophilic varieties cause forms of dermatophytosis, that is, fungal infection of the skin. They are keratinophilic: they feed on the keratin in nails, hair, and dead skin.
Trichophyton concentricum causes "Malabar itch", a skin infection consisting of an eruption of a number of concentric rings of overlapping scales forming papulosquamous patches.
Trichophyton rubrum and Trichophyton interdigitale cause athlete's foot (tinea pedis), toenail fungal infections (a.k.a. tinea unguium, a.k.a. onychomycosis), crotch itch (a.k.a. tinea cruris), and ringworm (a misnomer, as there is no worm involved; it is also known as tinea corporis). Trichophyton schoenleinii cause favus (tinea capitis),Trichophyton mentagrophytes var. mentagrophytes and Trichophyton verrucosum cause kerion (violent reaction results from infection with an animal dermatophytes). Fungal folliculitis is a rare hair follicle infection induced overwhelmingly by Trichophyton, which can be spread zoonotically. The fungi can easily spread to other areas of the body as well and to the host's home environs (socks, shoes, clothes, showers, bathtubs, counters, floors, carpets, etc.).
They can be transmitted by direct contact, by contact with infested particles (of dead skin, nails, hair) shed by the host, and by contact with the fungi's spores. These fungi thrive in warm moist dark environments, such as in the dead upper layers of skin between the toes of a sweaty foot inside a tightly enclosed shoe, or in dead skin particles on the wet floor of a communal (shared) shower. Their spores are extremely difficult to eliminate, and spread everywhere.
When the hyphae of the fungi burrow into the skin and release enzymes to digest keratin, they may irritate nerve endings and cause the host to itch, which may elicit the scratch reflex, which directs the host to scratch. Scratching directly transfers fungi and dead skin particles that are infested with the fungi to the fingers and under the finger nails. From there they can be transmitted to other parts of the host's body when the host touches or scratches those. Scratching also damages skin layers, making it easier for the fungi to spread at the site of the infection. If the fungi and infested debris are not washed from the fingers and fingernails soon enough, the fungi can also infect the skin of the fingers (tinea manuum), and burrow underneath and into the material of the fingernails (tinea unguium). If left untreated, the fungi continue to grow and spread.
Treatments
A variety of zoophilic and anthropophilic dermatophyte treatments have varying levels of success based on species type. Treatments may take up to six months.
References
External links
Doctor Fungus
Mycology Unit at the Adelaide Women's and Children's Hospital
Parasitic fungi
Arthrodermataceae
Cat diseases
Eurotiomycetes genera