Test 1 Cutaneous Mycosis- DermatoPHYtosis Flashcards by Preeti Gulve

Dermatophytosis is also known as

Ringworm

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Dermatophytosis is a form of _______ mycosis

Cutaneous mycosis

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T/F

Dermatophytosis is zoonotic

TRUE

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What is Dermatomycosis?

A cutaneous infection

caused by yeasts and saprophytic filamentous fungi

that resembles

dermatophytosis

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What type of dermatophytes are known as human reservoirs?

**Anthropophilic **dermatophytes

human reservoir

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What type of dermatophytes are known as

animal reservoirs?

**Zoophilic **dermatophytes

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What type of dermatophytes are known as

soil reservoirs?

**Geophilic **dermatophytes

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What is the only category of dermatophytes that includes the genus Epidermophyton?

**Anthropophilic **dermatophytes

include

Epidermophyton floccosum

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What are the 7 types of fungi

classified as

Anthropophilic Dermatophytes?

Epidermophyton floccosum
Trichophyton rubrum
T. tonsurans
T. schoenleinii
T. violaceum
Microsporum audouinii
Microsporum megninii

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What are the 6 fungi classified as

Zoophilic Dermatophytes?

Microsporum canis
M. equinum
M. gallinae
Trichophyton mentagrophytes
T. simii
T. verrucosum

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Geophilic dermatophytes

*only include *members of what

fungal family?

Geophilic dermatophytes

only include

Microsporum

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What are the 5 fungi

classified as

Geophilic Dermatophytes?

M. gypseum
M. nanum
M. persicolor
M. vanbrueseghemii
M. cookei

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The most common dermatophyte found in

catteries

belong to which group?

Zoophilic Dermatophytes

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What category of dermatophytes:

cause recurrent ringworm infections

is common of young animals kept in close proximity

include hot, humid conditions, trauma, and poor nutrition as predisposing factors

and

the *conidial survival *depends on moisture?

Zoophilic Dermatophytes

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T/F

Zoophilic dermatophyte spores are

heat resistent

FALSE

Geophilic Dermatophyte Spores

are heat resistent

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Infections by ________ dermatophytes

are sporadic

and

not readily transmitted between animals

Geophilic dermatophytes

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Infection by Geophilic dermatophytes

typically occurs during what season?

Geophilic dermatophyte infections

occur during

AUTUMN

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What is the most common dermatophyte of domestic species?

M. canis

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Genus microsporum

typically attack

what part of an animal’s body?

Microsporum attack

*hair *and skin

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Large, rough, thick-walled macroconidia

that are multiseptate

are characteristic of

what genus of fungi?

Genus Microsporum

^{have large, rough, thick-walled multiseptate macroconidia}

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Visually, how do the **macroconidia **of genus Microsporum differ from genus Trichophyton?

The macroconidia

of Microsporum are fusiform to obovate

where as

Trichophyton are cylindrical, cigar-shaped

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What are the 4 most common species of genus Microsporum?

M. canis*
M. gallinae*
M. gypseum*
M. nanum*

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What are the 3 most common species of Genus Trichophyton?

T. mentagrophytes*
T. equinum*
T. verrucosum*

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Which genus has smooth, thin-walled macroconidia?

Trichophyton

has smooth, thin-walled macroconidia

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In which genus are the macroconidia produced in **small numbers** and thus rarely seen?

Genus Trichophyton

Both Microsporum and Trichophyton attack

hair, skin, nails, and claws

Infections caused by _________ spp. are usually more severe because *more inflammation* is associated with it

**Trichophyton spp. **infections are **more severe **than Microsporum

The circular lesions in Canine Ringworm are up to ____ cm in diameter

**2.5 cm** lesions in canine ringworm

Canine ringworm is most commonly found on what 3 parts of a dog's body?

Face Elbows Paws

Canine ringworm is most commonly caused by which 4 species of dermatophytes?

* M. canis* * M. gypseum* * T. erinacei* * T. mentagrophytes*

Which species of dermatophyte that commonly causes Canine Ringworm is responsible for Kerion?

*T. mentagrophytes* responsible for kerion in canine ringworm

What is **kerion**?

**Intense inflammation, ulceration, and prululent exudation** commonly caused by *T. mentagrophytes* in Canine Ringworm infections

Dogs that compulsively bury objects in soil are most likely to be affected by which species of dermatophytes causing canine ringworm?

**M. gypseum** seen in compulsive burying

Dogs that are **good rat catchers** are more commonly afflicted by canine ringworm caused by \_\_\_\_\_\_\_\_\_\_\_?

*T. mentagrophytes*

Kerion more commonly affects dogs that exhibit what type of behavior?

Dogs that are **good rat catchers** are more likely to get kerion

Dogs that are **avid hedgehog worriers** are more likely to be afflicted by what canine ringworm causing dermatophyte?

*T. erinacei*

CATS serve as the primary reservoir for

**m. canis**

Ringworm in which animal is often asymptomatic which poses a risk to public health?

**Cats**

Feline **otitis** is caused by which dermatophyte?

**m. canis**

T/F It is rare for cows to get ringworm

FALSE **bovine ringworm** is COMMON

The incidence of bovine ringworm is higher during what season?

Winter

Most bovine ringworm infections are caused by which dermatophyte?

*T. verrucosum*

Large circumscribed plaques and secondary bacterial infection are clinical signs of ringworm in which species of animal?

Cows

What breeds of pigs are most susceptible to porcine ringworm?

**Large breed pigs** are more susceptible

*Microsporum nanum* causes most ringworm infections in which species of animal?

**Pigs** M. nanum is the most likely cause of porcine ringworm

What are the 4 species of dermatophytes known to cause porcine ringworm?

***m. nanum*** * m. gypseum* * m. canis* * t. mentagrophytes*

In which species of animal is **alopecia** NOT a clinical sign of ringworm infection?

**Pigs** usually have no loss of hair in porcine ringworm infections

Equine ringworm is most commonly caused by which 2 species of dermatophytes?

* T. equinum* * M. gypseum*

In which species of animal would you observe the following clinica signs of ringworm infection? **Matted Hair** **Moth-eaten appearance **caused by enlarged lesions

Horses

In which species of animal do ringworm infections often become **chronic and subclinical **and also **recur under stress**?

Horses

Poultry ringworm is caused by

**m. gallinae**

**Favus** is another name for ringworm infection in which species of animal?

Poultry/Birds get **Favus/ White comb**

Why is poultry ringworm called "white comb"?

Because the white lesions caused by m. gallinae in the combs of male birds can coalesce cover the entire comb with thick white coating

Dermatophytes in general do NOT invade or survive in these 2 types of cells/areas.

Dermatophytes will not invade or survive in **living cells** or **areas of intense inflammation**

Fungal virulence factors include these 3 enzymes

Fungal Proteases Fungal Keratinases Fungal Elastases

Which fungal virulence factor *weakens the hair shaft and results in breakage*?

Proteases

Which fungal virulence factor is *directly related to the **clinical severity** of **M. canis** infections*?

Keratinases

Inflammation is associated with this fungal virulence enzyme

Elastases ^{cause inflammation}

What is the major infective form of dermatophytes?

SPORES

Infection of dermatophytes can be caused by direct contact or exposure to \_\_\_\_\_\_\_\_\_ in the environment or on fomites

**arthroconidia** in the environment or on fomites

What are the 2 major classes of fungal antigens and what do they cause in the host?

**Glycopeptides** and **Keratinases** **Glycopeptides **stimulate *Cell Mediated *and *Humoral Immunity* **Keratinases** elicit *Delayed-Type Hypersensitivity reactions*

Wood's Lamp examination of lesions will cause which species of dermatophyte to *fluoresce green*?

**m. canis** will fluoresce green

In direct microscopic examination using 10-20% KOH, what finding is NOT considered significant?

The presence of macroconidia of transient fungi is NOT significant

A direct microscopic examination is considered positive if \_\_\_\_\_\_\_\_\_\_ is seen in *hair shafts and keratin scales*

Fine, Hyaline, Septate Hyphae ^{seen in hair shafts and keratin scales}

A direct microscopic examination is considered positive if \_\_\_\_\_\_\_\_ is seen on hair

Ectothrix arthroconidia ^{seen on hair}

Cultures are incubated on Dermatophyte Test Medium (DTM) at **25 - 30C** UNLESS \_\_\_\_\_\_\_\_\_ is suspected, in which case, incubation will be at **37C**

*T. verrucosum * grows at **37C**

In culture, Dermatophytes utilize protein peptones which causes an ________ reaction, turning _____ in color

Dermatophytes use peptones and cause **alkaline** reactions turning **RED**

When a fungi uses *sugar first* and then protein, what color is seen in the DTM?

**Yellow reaction = acidic reaction** when fungi uses sugar first

Growth on DTM with a **red slant** *BEFORE 10 days* indicates

Dermatophytes

**Nicotinic acid **is a growth requirement for which species of dermatophyte?

**T. equinum** requires *nicotinic acid* to grow

**Inositol** and **Thiamine** are growth requirements of which dermatophyte species?

**T. verrucosum** requires inositol and thiamine to grow

Macroconidium is used in the identification of species of which genus of dermatophyte?

Microsporum is identified using *macroconidia*

Physiological tests like nutritional requirements, temp tolerance, urease production and in-vitro hair perforation are performed in order to ID which genus of dermatophytes. Why?

Trichophyton because they do NOT produce macroconidia in large amounts, and are rarely seen

What do you prescribe to treat a **systemic fungal infection**?

**Azoles** (like Ketoconazole, Clotrimazole and Itraconazole) or **Terbinafine** ***Treat until 3 negative weekly cultures***

**Vaccination **is an effective method of preventing fungal infection in \_\_\_\_\_\_\_, but is NOT effective in \_\_\_\_\_\_

**Effective in COWS** NOT effective in **cats**

What are the 2 most common **zoonotic fungal species** causing disease in humans?

**M. canis** **T. verrucosum**