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36 Cards in this Set
- Front
- Back
What dermatophytes are pathogenic in dogs and cats?
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-Microsporum canis (most common)
-M. gypseum -Trichophyton mentagrophytes (seen in rodents) -Sporotrichosis? |
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How are Dermatophytes transmitted?
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Dermatophytes are transmitted by contact w/ infected hairs, scales, or fungal elements
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What are typical lesions and distribution patterns of dermatophyte infections in dogs?
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-Classic lesions: annular areas of peripherally expanding alopecia, scale, crust, papules and pustules
-Nasal folliculitis and furunculosis -Generalized seborrhea-like infection -Dermatophytic kerion -Onychomycosis (nail infection) M. Canis Head and front limbs M. gypseum Extremities and tail T. mentagrophytes Whole body |
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What are typical lesions and distribution patterns of dermatophyte infections in cats?
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-Generalized infections are more common:
-Alopecia -Folliculitis, erythema, scale, crust, papule -Generalized seborrhea like eruption -Milliary dermatitis = uncommon to be caused by dermatophytes (usually caused by fleas) -Localized infections: -One or more annular areas of alopecia -May mimic chin acne or “stud tail” -Onychomycosis -Dermatophyte kerion -Dermatophyte pseudomycetoma |
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How can you positively identify a fungal agent (genus and species)?
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-Most reliable test fore identification = Fungal culture
-Identify the organism through morphologic and microscopic characteristics -DTM (dermatophyte test medium) -Dermatophytes utilized the protein in the media first, leading to alkaline metabolites that cause the media to turn red w/in 10-14 days -Saprophytes utilized carbohydrate first creating acidic metabolites |
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Why is it important to make a definitive diagnosis for a dermatophyte infection?
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is important to make a definitive diagnosis in order to properly clear up the problem and prevent re-infection
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What recommendations would you make for a cattery w/ dermatomycosis in each litter of kittens (M canis)?
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-Cessation of breeding program
-Identification and isolation of positive animals -Topical and systemic therapy for positive animals -Topical therapy for contact cats -Strict environmental control -Treat all cats until cats are culture negative 3 times -Toothbrush cultures to screen healthy appearing cats for carrier status |
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What skin layer do dermatophytes grow in?
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-Keratogenous zone of keratinized tissue (Adamson’s fringe)
-Hair, nail, stratum corneum of skin -Don’t affect the hair bulb |
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Describe the lesions seen with Cryptococcus.
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-Cutaneous lesions including nodules, ulcers and draining tracts
-Nasal discharge and sneezing -Ocular involvement = blindness -Neural involvement = seizures, ataxia, paresis |
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What are the risk factors associated with cryptococcus?
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More common in cats
Found in pigeon shit |
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How is cryptococcus diagnosed?
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-Cytology
-Biopsy -Serology |
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What are the treatment options for Cryptococcus?
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-Itraconazole
-Fluconazole -Flyctosine |
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What are the clinical signs of Malassezia dermatitis in a dog?
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-Very pruritic
GENERALIZED: -Erythematous, greasy, scaly, crusty, malodorous, lichenification, alopecia, hyperpigmentation LOCALIZED: -Otitis, lips, muzzle, interdigital spaces, ventral neck, medial thigh, groin, axilla, paronychia, intertriginous regions -40% have concurrent bacterial pyoderma |
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What are the clinical signs of Malassezia dermatitis in a cat?
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-Not as common as dog
GENERALIZED: -Erythematous, scaly to waxy dermatitis LOCALIZED: -Otitis, chin acne, paronychia (base of nail) |
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How do you diagnose Malassezia?
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-Cytologic exam:
-Impression smear, swab, skin scraping, acetate prep -Look for round to oval budding yeast “peanut shaped” -Skin biopsy w/ histopath -Culture -Look for a response to anti-yeast therapy |
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Discuss Treatment for Malassezia.
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-Identify and address the underlying cause:
-w/ out correction of the predisposing disease or factors, the disease is likely to reoccur -Treat concurrent Staph pyoderma Topical therapy: -Anti-fungal creams or lotions for localized areas -Anti-fungal shampoos for generalized areas -Dips are not necessary but can be effective Systemic therapy: -Ketoconazole or Itraconazole -**Griseofulvin is NOT effective** -Treat 7-14 days past clinical cure |
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What are the predisposing factors for Malassezia?
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-Increased humidity
-Immune dysfunction -Genetic (Basset’s or WHWT) -Hypersensitivity -Keratinization disorders -Endocrine or metabolic disorders |
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Which of the following are zoonotic? Blastomycosis, Histoplasmosis, Coccidiomycosis, Crytococcus neoformans.
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Cryptococcus neoformans
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What are some clinical signs associated with Blastomycosis?
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-Nodular skin lesions
-Draining tracts -Absscesses -Often have concurrent respiratory disease |
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What are some clinical signs associated with Histoplasmosis?
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-GIT and respiratory disease
-Granuloma and draining tract skin lesions |
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What are some clinical signs of Coccidomycosis?
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Dog:
-Young, male dogs -Coughing, dyspnea, fever, anorexia, wgt. Loss, lameness, ocular disesase -Papules, nodules, abscesses, draining tract, ulcers -Skin infections often occur over infected bone Cat: -RARE -Anorexia, wgt. Loss, cough, dyspnea, lameness, ocular disease, skin lesions |
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What are some clinical signs of Cryptococcus neoformans infection?
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-Cutaneous lesions include nodules, ulcers, draining tracts
-Nasal discharge -Ocular involvement = blindness -Neural involvement = seizures, ataxia, paresis |
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What are some physical characteristics of Blasto?
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-Broad based budding
-Endemic in Mississippi and Ohio river valley -Ingested or inhaled from: soil, bird or bat shit |
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What are some physical characteristics of Histo?
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-Tiny organism
-Endemic in Eastern US |
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What are some physical characteristics of Coccidio?
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-Largest organism w/ spherules that contain endospores
-Found in sandy, alkaline soil, high temperature, low rainfall, low elevation -Endemic in SW US, South and Central America |
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What are some physical characteristics of Cryptococcus neoformans?
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-Large organism
-Relatively common in cats -Found in pigeon shit -Thick candy shell |
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Which breed of dog is predisposed to developing cutaneous infections w/ pythium?
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GSD
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What is the usual source of pythium infection?
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Swamps or ponds in southern US
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How is pythium treated?
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Aggressive surgery (amputation)
-Itraconazole + Terbenafine -Treat for 2 months and recheck titers at LSU |
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What is the prognosis for pythium?
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Poor (“swamp cancer” is invasive and often fatal)
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What is an asymptomatic carrier?
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animal that is carrying and possibly shedding a disease without showing any clinical signs
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How are asymptomatic carriers identified?
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Screening tests
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How are Malassezia infections transmitted?
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Malassezia is part of the normal flora of ears and skin. It is an opportunistic pathogen that proliferates under conditions of increased moisture (i.e. greasy, scaly, inflamed skin)
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Does antibiotic therapy predispose animals to yeast or fungal infections of skin?
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Yes
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What is the most common subcutaneous fungal infection of cats and dogs?
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Microsporum canis
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What are the risk factors for infection with Blasto?
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-Found in the Mississippi and Ohio River valley
-Found in nitrogen rich soil and bat and bird shit |