Test 1 Cutaneous Mycosis- DermatoPHYtosis Flashcards
Dermatophytosis is also known as
Ringworm
Dermatophytosis is a form of _______ mycosis
Cutaneous mycosis
T/F
Dermatophytosis is zoonotic
TRUE
What is Dermatomycosis?
A cutaneous infection
caused by yeasts and saprophytic filamentous fungi
that resembles
dermatophytosis
What type of dermatophytes are known as human reservoirs?
**Anthropophilic **dermatophytes
=
human reservoir
What type of dermatophytes are known as
animal reservoirs?
**Zoophilic **dermatophytes
What type of dermatophytes are known as
soil reservoirs?
**Geophilic **dermatophytes
What is the only category of dermatophytes that includes the genus Epidermophyton?
**Anthropophilic **dermatophytes
include
Epidermophyton floccosum
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
What are the 6 fungi classified as
Zoophilic Dermatophytes?
- Microsporum canis
- M. equinum
- M. gallinae
- Trichophyton mentagrophytes
- T. simii
- T. verrucosum
Geophilic dermatophytes
*only include *members of what
fungal family?
Geophilic dermatophytes
only include
Microsporum
What are the 5 fungi
classified as
Geophilic Dermatophytes?
- M. gypseum
- M. nanum
- M. persicolor
- M. vanbrueseghemii
- M. cookei
The most common dermatophyte found in
catteries
belong to which group?
Zoophilic Dermatophytes
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
T/F
Zoophilic dermatophyte spores are
heat resistent
FALSE
Geophilic Dermatophyte Spores
are heat resistent
Infections by ________ dermatophytes
are sporadic
and
not readily transmitted between animals
Geophilic dermatophytes
Infection by Geophilic dermatophytes
typically occurs during what season?
Geophilic dermatophyte infections
occur during
AUTUMN
What is the most common dermatophyte of domestic species?
M. canis
Genus microsporum
typically attack
what part of an animal’s body?
Microsporum attack
*hair *and skin
Large, rough, thick-walled macroconidia
that are multiseptate
are characteristic of
what genus of fungi?
Genus Microsporum
have large, rough, thick-walled multiseptate macroconidia
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
What are the 4 most common species of genus Microsporum?
- M. canis*
- M. gallinae*
- M. gypseum*
- M. nanum*
What are the 3 most common species of Genus Trichophyton?
- T. mentagrophytes*
- T. equinum*
- T. verrucosum*
Which genus has smooth, thin-walled macroconidia?
Trichophyton
has smooth, thin-walled macroconidia
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
