Unit 1 - Mycoses Flashcards Preview

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Flashcards in Unit 1 - Mycoses Deck (64):

What are most fungi considered

Opportunistic pathogen's


What causes a fungal proliferation

Treatment with antibiotics which wipes out normal bacteria microflora, decreased immune system secondary to neoplasia, corticosteroids, diabetes mellitus


Describe the characteristics of fungal infections

Chronic and slow progressing. Inflammatory response is granulomatous, immunity is cell mediated


What is Dermatophytosis a.k.a. ringworm

Contagious infection of keratinized skin, hair, claws. Caused by one of several species of superficial fungi, the dermatophytes


Describe the host range for ringworm

Species are host adapted, but can cross host barriers. Any animal species may contact her dermatophytosis. Particularly important in cats and is zoonotic.


What is the general age range infected with ringworm

Most commonly a disease of young animals do to immaturity of immune system


What are the risk factors for dermatophytosis

Immune deficiency. Inadequate husbandry conditions, high population density, stress, poor nutrition


Which are the breeds of cats that are predisposed to dermatophytosis

Persians and Himalayan's


What are the most common dermatophytes of cats and dogs

Microsporum canis
Microsporum gypseum
Trichophyton mentagrophytes


Describe the dermatophytosis lesions

Circular areas of alopecia and scaling patches with central hair regrowth and inflamed edges. Often multiple lesions. Not all lesions are classic


Describe where the dermatophytosis lesions are on dogs

Face or paws


Describer where the dermatophytosis lesions are on cats

Ear pinnea and face


Why is dermatophytosis underdiagnosed in cats

Due to the variation in lesion presentation


How do you diagnose dermatophytosis

Woods lamp. Look for Applegreen florescence. Not all dermatophytes fluoresce. Fungal culture to confirm diagnosis and monitor treatment


What percentage of microsporum canis strains will flouresce a bright green color upon exposure to a uv light



What materials can cause a false positive when diagnosing ringworm

Scales or dandruff and topical products which can florescence


How do you confirm that it's a true positive when diagnosing ringworm

Bright green in hairs only. Allow the lamp five minutes to warm up


What do you do when you have fluorescing hairs in diagnosing ringworm

Sent for fungal culture. Pluck hair from edges of lesions using a sterile hemostat and submit. Or a toothbrush is vigorously combed over the lesions for 2 to 3 minutes. Wrap in plastic to submit to laboratory


Name the in clinic fungal culture method

DTM. Dermatophyte testing medium. Place hair on culture medium or inbed toothbrush. Cover plates and incubate at room temperature. Watch daily for growth.


How do you know that you have ringworm based on a culture

Look for off-white, fluffy to powdery colony with the red color change in the medium at the same time that the colony first appears. Examine them under the microscope for confirmation


How quickly does ringworm grow on culture medium

Growth happens within 7 to 14 days though plates are kept for 21 days before being deemed negative for growth


How do you perform the microscopic confirmation of ringworm

Brush a strip of clear tape over the colony. Mount tape sticky side down onto a drop of methyl blue on a microscope slide. Examine it 10 X to 40 X for typical appearance of dermatophyte macroconidia


Describe the appearance of microsporum canis generally speaking

Canoe shaped, thick walled macroconidia with terminal knobs


Describe how you would microscopically identify microsporum gypseum

Numerous thin walked macroconidia with slightly rounded proximal ends


Describe how you would microscopically identify trichiphyton mentagrophytes

Cigar shaped microconidia which may be few in number. Numerous globose microconidia . Spiral hypae might be present


How do you treat ringworm

Usually self limiting. Treatment strongly advised to accelerate recovery and minimize spread l


What does the best treatment for ringworm include

Topical, systemic and environmental treatment


How long do you do a treatment for ringworm

Continued until clinical and ideally mycologic cure is achieved, usually 8-16weeks


At what time in treatment do you repeat fungal culture for ringworm

After 2 months of treatment then once per month until 2 negative culture


Give an example of a ringworm topical treatment

Imaverol dilution with e collar.


Describe a systemic treatment for ringworm for dogs as well as cats

Itrafunol for cats. Ketoconazole in dogs.


Describe an environmental treatment for ringworm

Disinfect environment with diluted bleach


How is ringworm transmitted

Direct contact or fomites.


What is the protocol you should follow with ringworm

Handle infected patients with gloves and wash your hands. Disinfect cages and consultation tables with diluted bleach. Remind owners of the zoonotic nature of disease


Describe malassezia pachydermatis

Pear shape yeast. Part of normal flora of ear in small quantities. Can cause otitis externa in dogs, uncommon in cats and can also cause dermatitis


What are the predisposing factors of otitis externa

Conformation, lifestyle, obstructive lesions


Describe which conformations are most susceptible to otitis externa

Cocker spaniels, basset hounds, beagles, sharpeis, english Bulldogs, chow chows, poodles


What life style factors can predispose you to otitis externa

Swimming, grooming, excessive ear care


What types of obstructive lesions can cause otitis externa

Polyps, neoplasia


How do you treat otitis externa

Topical antibacterial, Antifungal, glucocorticoid combination therapy


What is malassezia dermatitis caused by

Secondary to allergies and excessive licking.


How do you treat malassezia dermatitis

Treated topically (surolan) or systemically (itraconazole)


Describe Candida albicans

Part of the normal flora of the mouth, intestine, lower urogenital tract of animals and humans


Describe the virulence of Candida albicans

Opportunistic, can invade locally and usually causes superficial infections of skin and mucosa. Can cause systemic infections in severely immunocompromised patients


What are different examples of candida

Whitish hyperkeratitis on tongue, mouth, stomach. Diaper rash in babies. Mastitis in cows. Vaginitis in women


What is a blastomyces dermatitidis

Slow growing dimorphic fungus. Mold form in the environment and very large yeast in the body. Most common systemic mycotic infection


Describe blastomycosis

Can affect many mammalian species but occurs most often in people and dogs. Outdoor roaming dogs near waterway have increased risk. Majorly August-October


Describe the dissemination of blastomycosis

Young male hunting dog inhales spores. Spores germinate in lung to large budding yeast form, most individual resist infection. Predisposition/heavy load leads to development of chronic granulomatous pneumonia. Usually then disseminates to skin, bone, prostate, testes, eyes. Blocks capillaries and forms ulcerations.


What are the clinical signs of blastomycosis

Fever, cough, weight loss, lameness, skin ulcers, uveitis


Describe histoplasma capsulatum

Dimorphic fungus, small yeast in tissue.


Where is histoplasmosis found

Mostly in soil, especially contaminated with bird or bat droppings


How do you get histoplasmosis

Inhalation of small microconidia. Oral exposure can also result in disease. Disease may remain confined to lungs, gi tract or may become disseminated.


What does histoplasmosis cause

Granulomatous pneumonia, lymphadenopathy, colitis, emaciation


What is cryptococcosis

Dimorphic fungus with the yeast phase Being infective. The yeast is fast growing and slimy.


What does c. Neoformans var. neoformans affect

Immunocompromised individuals. Frequent in bird manure


What does c. Neoformans var. Gatti affect

More virulent, can affect healthy individuals, associated with plant debris


What are the forms of cryptococcosis

Respiratory, cutaneous, cns, ocular forms


Describe cryptococcosis in cats

Unilateral or bilateral nasal discharge, sneezing, firm swelling over bridge of nose, submandibular lymphadenopathy


What can cryptococcosis cause in cats or dogs

Multifocal neurologic signs, ocular abnormalities, cutaneous lesions


What is aspergillosis

Mold. Causes regional or disseminated infection. Dogs more commonly affect than cats.


What breeds does systemic aspergillosis affect

Middle aged German shepherd


What breeds are affected with nasal aspergillosis

Medium to large breed dogs


Describe the appearance of aspergillus fumigatus

Common grey green mold found on moldy bread, cheese and oranges.


Describe aspergillus fumigatus

Causes a wide variety of disease depending on host predisposition. Can cause chronic sinusitis in dogs, cats, horses.