Dermaphytes Flashcards
T/F: Dermaptophyte infections are the most common fungal infections in vet med
TRUE
Where do dermatophytes have a tropism to?
Keratin
superficial keratinized epithelium- hair and nails
Are dermatophytes zoonotic?
YES
T/F: Dermatophyte infections are typically self limiting
TRUE
What factors predispose animals to dermatophyte infections?
Young, poor nutrition, high humidity, scratching/rubbing
When are cattle the most predisposed to dermatophyte (specifically ringworm) infections?
In the winter due to low UV light - when housed indoors
T/F: Anthropophilic is a term used for dermatophytes that infect arthropods
FALSE
anthropophilic = human reservior
Who or what are the reservoirs for zoophilic dermatophytes and geophilic dermatophytes?
Zoophilic = animals
Geophilic = soil or environmental
What are the three species of ring worm most commonly seen in dogs, cats, and humans?
Microsporum canis
Microsporum audouinii
Microsporum gypsium
T/F: If a cow has a ring worm infection, it is most likely caused by Trichophyton verrucosum
TRUE
What is the agent of ring worm for horses, and the agent for pigs?
Horses - Trichophyton equinum
Pigs - Microsporum nanum
What are characteristics of a dermatophyte infection?
slowly expanding circle of alopecia and desquamated epithelium - central area will have hair regrowth
When testing for ring worm, from where should you collect your sample?
The outer edge of the lesion - NOT THE CENTER
T/F: Dermatophytes always cause superficial skin infections with alopecia
False
They do MOST of the time but “not all ringworm is classic”
Sometimes they can form granulomatous and nodular lesions
Who are the main carriers of mycosporum canis?
CATS - often are asymptomatic carriers
*most ringworm infections of cats and dogs is due to - microsporum canis and M. gypsium
Does Trichophyton mentagrophytes have a wide or narrow host range when compared to micosporum species?
WIDER HOST RANGE
What is a kerion lesion?
Nodular lesion caused by dermatophytes, localized, or generalized. Often with furnuculosis
If a Persian cat presents with a SQ nodule - what may you expect it to be? (think fungus)
Pseudomycetoma - caused by Microsporum canis
Does the species of dermatphyte matter for treatment?
NO
It matters for controlling infection - so you know who the proper host is
The most common animal humans get ringworm infections is from…?
CATS
T/F: Mycosporum canis infection will glow in the dark and this is used to diagnose infections
FALSE
Does not glow in the dark, but you can used a Woods Lamp to detect fluorescence of microsporum infections
T/F: There is no preparatory step to be done to the lesion before collecting a sample
FALSE
disinfect the area with 70% alcohol
then pick hairs of affect lesion and send it DRY. Tubes should not be tightly closed to prevent moisture
What might you see on a microscopic evaluation of a hair sample of a patient with ringworm?
Large number of spores - arthrocondia on broken hairs
You’re tech looks at a sample of hair from a patient with ringworm under the microscope and tells you she sees endothrix arthrocondia; what does that mean? Why is it imporant
She is describing the location of the spores
Ectothrix = outside the hair follicle
Endothrix = inside the hair follicle
This can be used for species identification
T/F: Performing your own in house culture is an acceptable way to diagnose ringworm infections
TRUE
perform culture - if agar changes color (Red) and grows - they you perform a scotch tape prep and use lactophenol cotton blue staining to confirm
OR - can use pre made Dermatophyte test media
Who does Microsporum gallinae infect? What does it cause?
Chickens - causes Favus
Causes white lesions on comb and wattles - very itchy and irritating
Is treating/disinfection the environment recommended when dealing with a ring worm infection?
YES
clean/disinfect environment - clean bedding etc
Are there vaccines available for ringworm?
Yes - available for cats and cattle
not widely used
Where does Malassezia app have tropism for and what do they cause?
They are lipophilic yeast - like oily areas
***Often cause ear infections - otitis externa and superficial moist dermatitis
T/F: Dermatophytes sometimes cause systemic infections
FALSE
