Microsporum canis is distinguished from other dermatophytes within this genus by a hair perforation test. Microsporum canis shows a positive hair perforation test telling the observer that this type of dermatophyte grows into the hair shaft causing brittle breakable hairs. Another less sensitive test that can be used to diagnose Microsporum canis is the use of a Wood’s lamp, a fancy name for a certain wavelength of blacklight. Under the Wood’s lamp, Microsporum canis will fluoresce green, but only approximately 50% of the Microsporum canis strains will show fluorescence (1). After observation of either a positive hair perforation test or a positive Wood’s lamp test, the observer should then macroscopically and microscopically be able to distinguish this species from others due to the characteristcs mentioned in the description of the species above.
Microsporum canis is a dermatophyte found world wide causing tinea capitis and tinea corporis in humans. Microsporum canis has the ability to infect the keratinzed tissues such as the skin, hair and nails because of the virulent factor, keratinase(2). This species is zoophilic and the natural reservoir for Microsporum canis is dogs and cats, but can be equally virulent to humans, especially children. Humans generally contract ringworm through direct contact with an infected animal. To be sure this does not happen to you or your children, make sure your household pets, such as cats and dogs have been checked and treated for ringworm. If infected with Microsporum canis, griseofulvin is a drug that can be used, but less expensive and safer drugs have been developed such as oral terbinafine and intraconazole (1).
Microsporum canis, macroscopically, is a white to yellowish colony with a velvety/powdery texture approximately 3 to 9 cm in diameter. When the petri plate is flipped upside down, the colony ranges from being burnt orange to yellow depending on what strain of Microsporum canis may be growing on the plate(1).
Microsporum canis, microscopically, produces septate hyphae along with both macroconidia and microcondia. The Macroconidia are fusiform spindle-shaped approximately 35-125 X 7-20 micrometers in size. The macroconidia have thin septate walls within them with approximately 6-15 cells (1). The macroconidia’s outer walls tend to be very thick and rough. The microconidia also produced by this species are clavate and 4-7 X 2.5-3.5 micrometers in size (1).
As mentioned earlier, Microsporum canis can be found world wide infecting domestic cats and dogs, wild cats and dogs, humans and less commonly monkeys, horses, and rabbits. The only soil reported findings have been reported from sand beaches in Hawaii and soil in Romania (2).
Other taxa that may look similiar to Microsporum canis are other dermatophytes such as the genera Epidermophyton and Trichophyton. Although Microsporum species can be distinguished from these other two genera by having spindle-shaped macroconidia with rough enchinulate walls(3).
Microsporum canis is mostly a dermatophyte and can only be used by people for research as well as new and improved drug treatments. Although, maybe not Microsporum canis the species itself, but other dermatophytes are used by South American and African tribes as a sign of beauty. Some of the dermatophytes form geometrical shapes on the skin, which is known to be aesthetically pleasing in these tribes.
Microsporum canis ist ein parasitisch auf der Haut vorkommender Pilz (Dermatophyt). Er ist ein vor allem bei Katzen (Katzenpilz) und Hunden häufiger Erreger einer Dermatophytose und gehört zu den zoophilen Dermatophyten. Auch beim Menschen und bei anderen Säugetieren kann er eine Erkrankung auslösen, womit er ein Zoonoseerreger ist. Die Infektion mit M. canis (Mikrosporie) ist die häufigste „Urlaubsdermatophytose“, weil in südlichen Ländern über 90 % der streunenden Tiere infiziert sind, zum Teil ohne selbst Krankheitsanzeichen zu zeigen. Bei der einheimischen Katzenpopulation sind etwa 20 % der Tiere, meist symptomlose, Träger.[1]
Auf Nährböden bildet der Pilz watteartige und scharf begrenzte Kolonien, die zunächst cremeweiß, später orange-gelblich gefärbt sind. Im mikroskopischen Bild zeigt er septierte Hyphen und wenige glatte und keulenförmige Mikrokonidien entlang der Hyphen. Die zahlreichen spindelförmigen Makrokonidien sind 10–25×35–110 µm groß, haben 6 bis 18 Kammern, knotenförmige Enden und eine dicke, raue Wand.
Microsporum canis ist ein parasitisch auf der Haut vorkommender Pilz (Dermatophyt). Er ist ein vor allem bei Katzen (Katzenpilz) und Hunden häufiger Erreger einer Dermatophytose und gehört zu den zoophilen Dermatophyten. Auch beim Menschen und bei anderen Säugetieren kann er eine Erkrankung auslösen, womit er ein Zoonoseerreger ist. Die Infektion mit M. canis (Mikrosporie) ist die häufigste „Urlaubsdermatophytose“, weil in südlichen Ländern über 90 % der streunenden Tiere infiziert sind, zum Teil ohne selbst Krankheitsanzeichen zu zeigen. Bei der einheimischen Katzenpopulation sind etwa 20 % der Tiere, meist symptomlose, Träger.
Auf Nährböden bildet der Pilz watteartige und scharf begrenzte Kolonien, die zunächst cremeweiß, später orange-gelblich gefärbt sind. Im mikroskopischen Bild zeigt er septierte Hyphen und wenige glatte und keulenförmige Mikrokonidien entlang der Hyphen. Die zahlreichen spindelförmigen Makrokonidien sind 10–25×35–110 µm groß, haben 6 bis 18 Kammern, knotenförmige Enden und eine dicke, raue Wand.
Microsporum canis is a parasitisch af da Haut voakummanda Puiz (Dermatophyt). Ea is a voa oim bei Kotzn und Hundn haifiga Earega vo ana Dermatophytose und gheat zu de zoophiln Dermatophytn. Aa beim Mensch und bei ondan Saigeviechan ko ea a Eakronkung auslesn, womid'a an Zoonoseearega is. De Infektion mid M. canis (Mikrosporie) is de haifigste „Urlaubsdermatophytose“, wei in sidlichn Ländan iwa 90 % vo de [[streunendn Viecha infiziat san, zum Tei ohne sejbst Kronkheitsozeichn zu zoang. Bei da eihheimischn Kotznpopulation san uma 20 % vo de Viecha, meist symptomlose, Träga.[1]
Af Neahrbödn buidt da Puiz watteoatige und schoaf begrenzte Kolonien, de znächst cremeweiß, spada orange-gejbli gfeabt san. Im mikroskopischn Buid zoagt a septiate Hyphen und wenige glotte und keijnfeamige Mikrokonidien entlong vo da Hyphn. De zoihreichn spindlfeamign Makrokonidien san 10–25×35–110 µm grouß, hom 6 bis 18 Komman, knotnfeamige Endn und a dicke, raue Wond.
Microsporum canis is a parasitisch af da Haut voakummanda Puiz (Dermatophyt). Ea is a voa oim bei Kotzn und Hundn haifiga Earega vo ana Dermatophytose und gheat zu de zoophiln Dermatophytn. Aa beim Mensch und bei ondan Saigeviechan ko ea a Eakronkung auslesn, womid'a an Zoonoseearega is. De Infektion mid M. canis (Mikrosporie) is de haifigste „Urlaubsdermatophytose“, wei in sidlichn Ländan iwa 90 % vo de [[streunendn Viecha infiziat san, zum Tei ohne sejbst Kronkheitsozeichn zu zoang. Bei da eihheimischn Kotznpopulation san uma 20 % vo de Viecha, meist symptomlose, Träga.
Af Neahrbödn buidt da Puiz watteoatige und schoaf begrenzte Kolonien, de znächst cremeweiß, spada orange-gejbli gfeabt san. Im mikroskopischn Buid zoagt a septiate Hyphen und wenige glotte und keijnfeamige Mikrokonidien entlong vo da Hyphn. De zoihreichn spindlfeamign Makrokonidien san 10–25×35–110 µm grouß, hom 6 bis 18 Komman, knotnfeamige Endn und a dicke, raue Wond.
Microsporum canis is a pathogenic, asexual fungus in the phylum Ascomycota that infects the upper, dead layers of skin on domesticated cats, and occasionally dogs and humans.[1][2] The species has a worldwide distribution.[3]
Microsporum canis reproduces by means of two conidial forms, large, spindle-shaped, multicelled macroconidia and small, single-celled microconidia.[4][5] First records of M. canis date to 1902.[5] Evolutionary studies have established that M. canis, like the very closely related sibling species M. distortum and M. equinum, is a genetic clone derived from the sexually reproducing species, Arthroderma otae.[6] Members of Ascomycota often possess conspicuous asexual and sexual forms that can coexist in time and space. Microsporum canis exemplifies a common situation in ascomycetous fungi in which, over time, one mating type strain has undergone habitat divergence from the other and established a self-sustaining reproductive population that consists only of the asexual form.[3] It is hypothesized that asexual lineage of Microsporum canis evolved as a result of host-specific interactions, changes in ecological niche, as well as, geographic isolation of + and – mating types of Arthroderma otae, hence making it difficult to sustain sexual reproduction.[6] Early domestication of animals, such as cats and dogs, in Africa led to a later evolution of host-specific fungus, Microsporum canis, which is commonly associated with loose fur animals.[6] Nearly all reported isolates of Microsporum canis represent the "–" mating strain of A. otae.[6][7] Together with two closely related taxa, M. ferrugineum and M. audouinii, the clade is thought to have an African center of origin.[8]
Microsporum canis forms a white, coarsely fluffy spreading colony with a distinctive "hairy" or "feathery" texture.[4][5] On the underside of the growth medium, a characteristic deep yellow pigment develops due to the metabolites secreted by the fungus.[4][5] The intensity of this yellow pigmentation peak on the 6th day of colony growth and fades gradually making the identification of older colonies difficult.[4] Some strains of M. canis fail to produce yellow pigment altogether, exhibit abnormally slow colony growth and form undeveloped macroconidia.[4] Cultivation on polished rice tends to reestablish the typical growth morphology and is helpful for identification.[4]
Microsporum canis reproduces asexually by forming macroconidia that are asymmetrical, spherically shaped and have cell walls that are thick and coarsely roughened.[4][5] The interior portion of each macroconidium is typically divided into six or more compartments separated by broad cross-walls.[4][5] Microsporum canis also produces microconidia that resemble those of many other dermatophytes and thus are not a useful diagnostic feature.[3][4]
Microsporum canis produces infections of scalp and body sites, creating highly inflammatory lesions associated with hair loss.[3] Infection by this species can often be detected clinically using Wood's lamp, which causes infected tissues to fluoresce bright green[4][9] Fluorescence is attributed to metabolite pteridine, which is produced by the fungus in actively growing hairs.[3] Infected hairs remain fluorescent for prolonged periods of time (over the years), even after the death of the fungus.[3] Despite the frequent use of Wood's lamp in the clinical evaluation of ringworm infections, diagnosis of M. canis requires the performance of additional tests given the potential for false positives.[10] Culture of the fungus is most commonly used to evaluate morphological and physiological parameters of growth, and confirm the identity of the agent. Growth of the fungus on Sabouraud's agar (4% glucose), Mycosel or rice medium characteristically yields the bright yellow pigment. Microscopic examination of the growth can show the presence of the typical, warted and spindle-shaped macroconidia, confirming the identity of the isolate as M. canis.[11] The In vitro hair perforation test, commonly used to differentiate many dermatophytes, is not particularly useful for this species as it reveals the formation of "pegs" that penetrate into hair shafts - a characteristic shared widely among many zoophilic species.[5][12] Genetic analyses can be useful to establish the identity of atypical strains of M. canis; however the highly characteristic appearance of this species generally obviates the need for this more sophisticated method.[1][13]
Most M. canis infections are caused by the "-" mating strain of its sexual progenitor, Arthroderma otae.[3]
Microsporum canis has no specific growth factor or nutrition requirements, hence it grows well on most commercially available media.[5] In addition, M. canis exhibits rapid colony growth at 25 °C.[5] Two growth media that help distinguish M. canis from other Microsporum spp. (notably the morphologically similar species, M. audouinii) - specifically polished rice and potato dextrose agar.[4] On potato dextrose agar, M. canis produces a lemon-yellow pigment that is easily visualized, due to the presence of aerial hyphae, while on the polished rice, most isolates (even atypical strains) produce yellow pigment.[4][5]
It is considered a zoophilic dermatophyte, given that it typically colonizes the outer surface of animal's body.[4] Hence, animals, cats and dogs are believed to be the population hosts of this fungus, while humans are occasional hosts, in which the fungus can induce secondary infections.[4] Microsporum canis has been identified as a causal agent of a ringworm infection in pets, tinea capitis and tinea corporis in humans, children in particular.[2][3][5][14][15]
Microsporum canis is among the most common dermatophytes associated with tinea capitis and tinea corporis.[3][5] Unlike some dermatophyte species, M. canis typically does not cause large epidemics. Humans become infected as a result of direct or indirect contact with infected pets.[1][2][3] Microsporum canis generally invades hair and skin; however, some nail infections have been reported.[3] When hair shafts are infected, M. canis causes an ectothrix-type infection where the fungus envelopes the exterior of the hair shaft without the formation of internal spores.[4] This colonization of the hair shaft causes it to become unsheathed, resulting in characteristic round or oval non-inflammatory lesions the develop on the scalp.[4][9] Infection triggers an acute leukocytic reaction in subcutaneous tissues, which gradually becomes highly inflammatory and leads to hair loss, in the case of tinea capitis.[3]
Typically, infections caused by M. canis are associated with alopecia in the case of tinea capitis, while ringworm infections in pets produce characteristic inflammatory lesions, which may or may not result in hair loss.[3] This species has a propensity to cause subclinical infections in some animal species, particularly long-haired cats are frequent reservoirs of infection.[10] Isolation of the fungus from brushed pet hair can aid in detection of either an actively growing fungus or a passive carriage of fungal hyphae or arthroconidia.[10] In asymptomatic cases it is highly recommended to perform both Wood's lamp examination and microscopic analyses of suspected areas.[10][16] In the case of transient carriers, lack of clinical manifestations is accompanied with low number of M. canis colonies, number of which declines upon re-testing.[10]
Microsporum canis infections can be easily managed by topical antifungal agents; however severe cases may necessitate systemic therapy with griseofulvin, itraconazole or terbinafine.[1][9] Treatment of human cases also requires the identification and elimination of the infectious reservoir, which typically involves the investigation and treatment of colonized animals and the elimination of infected bedding and other environmental reservoirs.[10]
Despite its species name ("canis" implies dogs), the natural host of M. canis is the domestic cat. However this species can colonize dogs and horses as well. In all cases, it resides on the skin and fur.[10][13] Microsporum canis may also persist as dormant spores in the environment for prolonged periods.[10]
Microsporum canis species have a worldwide distribution.[1][3] Extremely high occurrence has been reported in Iran, while lower incidence is associated with England and Scandinavian countries, as well as South American countries.[3] Microsporum canis is uncommon in some parts of US and Europe, and is completely absent from equatorial Africa.[4]
Microsporum canis is a pathogenic, asexual fungus in the phylum Ascomycota that infects the upper, dead layers of skin on domesticated cats, and occasionally dogs and humans. The species has a worldwide distribution.
Microsporum canis on kottseente hulka kuuluv patogeenne seeneliik, mis põhjustab peamiselt kassidel ja koertel, kuid mõnikord ka inimestel dermatofüütiat.[1]
Microsporum canis’e kolooniad on valge kuni kollaka värvusega, sametise või puuderja struktuuriga.[2] Seen moodustab vaheseintega eraldatud hüüfe ning makro- ja mikrokoniide. Makrokoniidid on käävikujulised ja koosnevad 6 kuni 15 õhukese vaheseinaga eraldatud rakust. Suurus on neil umbes 35–125 × 7–20 μm ning need on ümbritsetud tugeva väliskestaga. Mikrokoniidid on 4–7 × 2,5–3,5 μm suurused nuijad moodustised.[2]
Peamised Microsporum canis’e looduslikud peremehed on kodukassid ja koerad, kellel nad koloniseerivad nahka ja karva. Spooridena suudavad nad väliskeskkonnas elus püsida kuni 15 kuud.[1] Maailmas on see liik väga laialt levinud. Eriti sage on ta Iraanis, veidi vähem Inglismaal, Skandinaavia riikides ja Lõuna-Ameerikas. Täielikult puudub ta ekvatoriaalses Aafrikas.[3]
Microsporum canis kuulub kolme peamise seeneliigi hulka, mis põhjustavad 95% loomade seenhaigustest.[1] Peamiselt haigestuvad kassid ja koerad, kuid seen suudab nakatada ka kõiki teisi imetajaid.[1] Nakatumine võib toimuda nii otsese kokkupuute kaudu haigestunud loomadega kui ka kaudselt, näiteks mööbli, kammide, harjade ja riiete kaudu.[1] Seened toituvad nahas, küüntes ja karvades leiduvast keratiinist.[1]
Microsporum canis põhjustab infektsiooni kehal ja pea piirkonnas. Nahale tekivad punased, kergelt põletikulised ringjad kolded, kus karvad on ühelt kõrguselt murdunud ning osaliselt välja langenud, lisaks tekib peenehelbeline nahaketendus.[1][4] Kui vaadelda haiguskoldeid Woodi lambiga tekib erkroheline fluorestsents, mis on omane veel mitmele teisele sama perekonna liigile.[4] Helendust tekitab ühend nimega pteridiin, mida seen toodab aktiivselt kasvavates karvades.[3] Lõplik diagnoos saadakse haiguskoldest võetud proovi laboratoorsete uuringute põhjal.[4] Küünte seennakkuse (küünte dermatofüütia) puhul küüs pakseneb ja selle värv luitub ning lõpuks küüs eemaldub.[1]
7 päeva vanune koloonia agaril
Makrokoniidid mikroskoobis 40x suurendusega
Microsporum canis on kottseente hulka kuuluv patogeenne seeneliik, mis põhjustab peamiselt kassidel ja koertel, kuid mõnikord ka inimestel dermatofüütiat.
Microsporum canis est une espèce de champignons du genre Microsporum responsable de plus de 90 % des cas de teignes chez le chien et le chat en France. Il contamine facilement l'homme, surtout l'enfant, et a également été retrouvé sur le hamster et le lion.
Microsporum canis è un dermatofita zoofilico, presente in tutto il mondo, frequente causa della tricofitosi (tigna) negli esseri umani, e in particolare nei bambini.
Invade i capelli, la pelle e raramente le unghie. I capelli invasi mostrano un'infezione del tipo ectotrix e presentano flourescenza giallo-verdastra alla luce ultravioletta.
I gatti ed i cani sono le principali fonti dell'infezione.
In "Sabouraud dextrose agar" le colonie si presentano piane, con una superficie densamente cotonosa, granulosa o polverulenta, che può mostrare alcune scanalature radiali. Le colonie hanno solitamente un colore che va dal giallo-dorato chiaro al giallo-brunastro, ma può capitare di trovare anche ceppi incolori.
Il M. canis si distingue dal M. audouinii, poiché perfora i capelli e cresce sui grani di riso, sui quali produce un tipico pigmento giallo-cupo.
Microsporum canis è un dermatofita zoofilico, presente in tutto il mondo, frequente causa della tricofitosi (tigna) negli esseri umani, e in particolare nei bambini.
Invade i capelli, la pelle e raramente le unghie. I capelli invasi mostrano un'infezione del tipo ectotrix e presentano flourescenza giallo-verdastra alla luce ultravioletta.
I gatti ed i cani sono le principali fonti dell'infezione.
In "Sabouraud dextrose agar" le colonie si presentano piane, con una superficie densamente cotonosa, granulosa o polverulenta, che può mostrare alcune scanalature radiali. Le colonie hanno solitamente un colore che va dal giallo-dorato chiaro al giallo-brunastro, ma può capitare di trovare anche ceppi incolori.
Microsporum canis ialah organisma yang boleh menyebabkan tinea kapitis pada manusia, dan kurang ringkas pada haiwan peliharaan.[1] Reservoir utama organisma ini pada haiwan teman adalah pada kucing dan anjing bela jinak. Di bawah uji kaji lampu Wood, ia memberikan pendarfluor hijau cerah 50% daripada masa.
Ia berkait rapat dengan dermatofit lain.[2]
. PMID 19457268.Selenggaraan CS1: Penggunaan eksplisit et al. (link) Selenggaraan CS1: Pelbagai nama: senarai pengarang (link) Microsporum canis ialah organisma yang boleh menyebabkan tinea kapitis pada manusia, dan kurang ringkas pada haiwan peliharaan. Reservoir utama organisma ini pada haiwan teman adalah pada kucing dan anjing bela jinak. Di bawah uji kaji lampu Wood, ia memberikan pendarfluor hijau cerah 50% daripada masa.
Ia berkait rapat dengan dermatofit lain.
Microsporum canis (anamorfe vorm) of Nannizzia otae (synoniem: Arthroderma otae) (teleomorfe vorm) is een schimmel die in de hoornlaag van de huid en op het haar voorkomt en een oppervlakkige schimmelinfectie kan veroorzaken. Het is een dermatofyt, die Tinea capitis en Tinea corporis veroorzaakt.[1][2] Vooral bij katten en honden komt de schimmel veel voor. In zuidelijke landen is 90% van de loslopende dieren besmet met deze schimmel.[3] Ook mensen kunnen na contact met besmette dieren door de schimmel geïnfecteerd raken.
Op een voedingsbodem met aangepast Leonian's agar vormt de schimmel een geel, harig schimmelpluis. Zes dagen na inoculatie is de gele kleur het diepst en vervaagt vervolgens geleidelijk.[4][2] Sommige isolaten vormen geen gele kleur, groeien abnormaal traag en vormen slecht ontwikkelde macroconidia.[4] Op geslepen rijst krijgen deze isolaten hun normale groei terug.[4] De asymmetrisch spoelvormige, 35-110 x 12-25 µm grote macroconidia[5] hebben vijf of meer tussenschotten en een dikke, ruwe celwand.[4][2] Microsporum canis produceert ook peervormige tot knuppelvormige microconidia.[1][4]
Microsporum canis (anamorfe vorm) of Nannizzia otae (synoniem: Arthroderma otae) (teleomorfe vorm) is een schimmel die in de hoornlaag van de huid en op het haar voorkomt en een oppervlakkige schimmelinfectie kan veroorzaken. Het is een dermatofyt, die Tinea capitis en Tinea corporis veroorzaakt. Vooral bij katten en honden komt de schimmel veel voor. In zuidelijke landen is 90% van de loslopende dieren besmet met deze schimmel. Ook mensen kunnen na contact met besmette dieren door de schimmel geïnfecteerd raken.
Op een voedingsbodem met aangepast Leonian's agar vormt de schimmel een geel, harig schimmelpluis. Zes dagen na inoculatie is de gele kleur het diepst en vervaagt vervolgens geleidelijk. Sommige isolaten vormen geen gele kleur, groeien abnormaal traag en vormen slecht ontwikkelde macroconidia. Op geslepen rijst krijgen deze isolaten hun normale groei terug. De asymmetrisch spoelvormige, 35-110 x 12-25 µm grote macroconidia hebben vijf of meer tussenschotten en een dikke, ruwe celwand. Microsporum canis produceert ook peervormige tot knuppelvormige microconidia.
Microsporum canis – gatunek dermatofitycznego grzyba zaliczany do rzędu Onygenales[1]. Wywołuje u ludzi i zwierząt grzybicę skóry owłosionej głowy[2].
Pozycja w klasyfikacji według Index Fungorum: Microsporium, Arthrodermataceae, Onygenales, Eurotiomycetidae, Eurotiomycetes, Pezizomycotina, Ascomycota, Fungi[1].
Kolonie są płaskie, białe do kremowych, z gęsto kosmatą powierzchnią, na której mogą być widoczne promieniste bruzdy. W koloniach zwykle obecny jest pigment jasno złotożółty do brązowawożółtego, jednak mogą również występować niepigmentowane szczepy. Makronidia są zazwyczaj wrzecionowate, z 5–15 komórkami, brodawkowate i grubościenne. Osiągają wymiary 35–110×12–25 µm[4].
Microsporum canis – gatunek dermatofitycznego grzyba zaliczany do rzędu Onygenales. Wywołuje u ludzi i zwierząt grzybicę skóry owłosionej głowy.
Microsporum canis [1][2] é um fungo que pode causar tinea capitis em humanos e dermatofitoses, em animais de estimação ("pets").[3] O maior reservatório desses animais é em gatos e cães domésticos. Sob iluminação UV (lâmpada de Wood), eles apresentam fluorescência verde brilhante 30–80% das vezes.[4]
Ele é relacionado de forma próxima com outros dermatófitos.[5]
Microsporum canis é um fungo que pode causar tinea capitis em humanos e dermatofitoses, em animais de estimação ("pets"). O maior reservatório desses animais é em gatos e cães domésticos. Sob iluminação UV (lâmpada de Wood), eles apresentam fluorescência verde brilhante 30–80% das vezes.
Ele é relacionado de forma próxima com outros dermatófitos.
犬小芽胞菌（學名：Microsporum canis）是小孢癬菌屬下的一種真菌，是造成皮膚感染的重要病源菌之一，對毛髮有高度感染力，主要感染貓、狗等寵物，但也可以對人類造成感染[2]。
犬小芽胞菌的菌絲具有隔膜，可產生大分生孢子與小分生孢子，大分生孢子是犬小芽胞菌最明顯的特徵之一，為梭形，由6-15個細胞組成，其上有不均勻的小刺或瘤狀物，外部呈粗糙狀並有厚壁結構，大小為35-110乘12-25微米[3]。小分生孢子的數量則較少，為單細胞，形狀為棒狀或梨形[1]。
在沙鮑弱氏瓊脂（一種常見的真菌培養基）中，犬小芽胞菌生長快速，於攝氏25度培養下約七天就可長成直徑3-9公分的菌落。菌落呈毛狀或棉狀，平坦或有少許溝槽。顏色從正面看為白色至淡黃色，從反面看為深黃色至黄橙色[1]。
犬小芽胞菌可感染人類的頭髮，造成頭癬，也可感染寵物的毛髮。其主要的宿主是貓、狗等寵物[4]，貓狗也是犬小芽胞菌造成人類感染的主要來源，犬小芽胞菌造成的頭癬通常由黑光燈的紫外線激發螢光來診斷[3]。犬小芽胞菌對寵物造成的感染非常嚴重，以台灣地區為例，從貓、狗身上分離的皮膚病菌種大部分都是犬小芽胞菌[2]，台北地區貓的皮膚感染更幾乎全部是犬小芽胞菌造成[5]。且因抗真菌劑的濫用，已初步確定犬小芽胞菌對某些抗生素產生了抗藥性，更增加治療上的困難，目前已有發展疫苗作為預防對策[5]。
另外，在極少數的個案中，犬小芽胞菌會感染免疫不全的宿主，造成足菌腫（英语：Eumycetoma）的症狀（屬皮下感染）[1]。
