Mycology - Midterm Flashcards
Geophilic dermatophytes in rodents, dogs and horses
- Microsporum gypseum
Golden retrievers and collies may be more susceptible. Infection via nasal tract.
- nasal aspergillosis in dogs
These occur in the form of round or oval bodies (budding)
- yeast
Hyphae penetrate medium and absorb nutrients
- vegetative mycelium
Sever difficulty breathing
- aspergillosis clinical signs
What is the route of infection for Coccidioides immitis and what are the main species infected?
- soil, or dust borne dimorphic fungus
- > infected by inhalation
- dogs are most effected
- > no dog to man transmission
Narrow spectrum drug. For Candida, Malassezia (yeast) infections only
- Nystatin
Treatment is Natamycin or Miconazole
- topical aspergillosis for keratitis in horses
Systemic anti-dermatophyte drugs
- griseofulvin and ketoconazole
Treatment of Histoplasma capsulatum?
- itraconazole or fluconazole oral
- > ketoconazole can also be used
- disseminated form has poor prognosis
- > when in advanced stages
Gutteral pouch mycosis and keratomycosis (keratitis)
- in horses
- caused by aspergillosis fumigatus
Which yeast causes myotic stomatitis and genital candidiasis in dogs and cats?
- Candida albicans
Diagnosis of Histoplasma capsulatum?
- histopath
- buffy coat smear
- serology
Is cryptococcus a commensal organism of the animal body?
- it is NOT a commensal organism, EXCEPT for in pigeons
Diagnoses of Malassezia pachydermatis?
- wet mount, gram stain and culture (fungal media)
Toxic, last choice antifungal therapy. For systemic infections only
- Amphotericin B
Which yeast causes otitis externa in dogs when there are too many?
- Malassezia pachydermatis
What is a common source of infection for Cryptococcus neoformans?
- pigeon/bird droppings
Treatment is Ketoconazole locally + Itraconazole
- systemic aspergillosis for horses
Narrow spectrum. Given orally for ring worm infection only.
- Griseofulvin
Zoophilic dermatophytes in cattle
- Trichophyton verrucosum
Collection of hair is for what diagnosis?
- ringworm
- > hair should be plucked, never cut
Brooder pneumonia
- in chickens
- caused by aspergillosis fumigatus
- conidiaophores
Also known as “Valley Fever”
- Coccidiodomycosis, or Coccidioides immitis
- > human disease
Laboratory procedure for Aspergillus
- scotch tape mounts in lactophenol cotton blue
Wood’s lamp, Wet mount KOH test or culture on Sabouraud medium used to diagnose.
- dermatophytes
Cell membrane consists of?
- ergosterol
Grow as yeasts and partly as elongated cells resembling hyphae which are called pseudo hyphae
- yeast-like fungi
What is the route of infection for Blastomyces dermatitidis and what are the main species infected?
- they are soil-borne
- > occur via aerosol inhalation -> granulomatous lesions in the lungs causing respiratory distress
- main species infected are dogs
How to diagnose Candida albicans?
- KOH wet mount, or gram stain - budding yeasts
- culture
Broad spectrum, used for a variety of fungal infections
- Ketoconazole (“Nizoral”)
Clinical signs of Histoplasma capsulatum?
- chronic cough, diarrhea and emaciation
Causes ringworm. Lesions restricted to skin, hair and nails. Alopecia, erythema and crusts.
- dermatophytes (zoonotic)
Laboratory procedure for Dermatophytes in hair/skin
- wet mount with 10% KOH
What are clinical signs of Cryptococcus neoformans?
- sneezing, snuffling, mucopurulent/hemorrhagic nasal discharge
How to diagnose Blastomyces dermatitidis?
- wet mount
- culture at 25’C will show mycelial form
Microsporum gypseum shape
- boat shaped
Zoophilic dermatophytes in dogs, horses and cats
- Trichophyton mentagrophytes
Which yeast causes metritis, vaginitis in horses?
- Candida albicans
Thick walled resting
- Chlamydospores
Hyphae projects above surface of medium and contain reproductive structures called conidia
- aerial mycelium
Signs of Coccidiodomycosis in dogs?
- dyspnea, weight loss, lymphadenopathy and seizures
Site of action of antifungal drugs, aphotericin B and azole group
- ergosterol
Which yeast causes crop mycosis (thrush) in poultry
- Candida albicans
- > white plaques
A polysaccharide which is the site of action for some antifungal drugs
- Chitin
Clinical signs of Malassezia pachydermatis?
- elephant-like skin
- chronic dermatitis (pruritis, alopecia, erythema)
Trichophyton mentagrophytes shape
- cigar shaped
Clotrimazole nasal infusion is the preferred treatment for
- nasal aspergillosis in dogs
- > second option is fluconazole systemic
- Ketoconazole can also be used
Destruction of turbinate bones and epistaxis (bleeding from nose)
- nasal aspergillosis
- in dogs
- caused by aspergillosis fumigatus
Which yeast has a bottle, or peanut, or footprint shaped yeasts in a gram stain?
- Malassezia pachydermatis
Reproduce by formation of different types of spores
- molds/filamentous fungi
Which yeast causes production of phospholipases, proteases and pseudomembranous ulcerative inflammation
- Candida albicans
Formed by segmentation and condensation of hyphae
- Arthrospores
Treatment of Malassezia pachydermatis?
- Ketoconazole oral for dermatitis!!
- > has the BEST activity against Malassezia
- Nystatin or clotrimazole tropical
Cell wall consists of ?
- chitin
What degree does fungi grow at?
- 25 degrees
Wet mount of colony using lactophenol cotton blue stain on aspergillosis will show?
- typical conidial heads
Which yeast causes enteritis in young animals on prolonged antibacterial therapy
- Candida albicans
Molds, or filamentous fungi
- fungi producing mycelia
Zoophilic dermatophytes in horses
- Trichophyton equinum
What yeast is commensal of the alimentary tract?
- Candida albicans
Microsporum canis shape
- spindle shaped
What yeast remains in yeast form at 25’C and in host at 37’C
- Cryptococcus neoformans
Types of dimorphic fungi
- Blastomycosis
- Histoplasmosis
- Coccidiodomycosis
How to treat Cryptococcus neoformans?
- Over 6 months of treatment may be needed and a minimum of 2 months for cats
- Itraconazole, fluconazole or ketoconazole
- solution of calcium hydroxide and sodium hydroxide is used to clean contaminated areas
- > MASKS should be worn
Ring worm fungi (skin)
- dermatomycoses
How to treat Blastomyces dermatitidis?
- itraconazole oral
- > about 60 days of treatment
These are fungi which exhibit yeast form in host tissue and in vitro at 37° C and mycelial form at 25 ° C
- dimorphic fungi
Diagnosis is 10% KOH wet mounts of deep scrapings (
- aspergillosis
Geophilic dermatophytes in pigs
- Microsporum nanum
What is the route of infection for Histoplasma capsulatum and what are the main species infected?
- soil enriched with bat or bird excreta
- > infection via inhalation
- dogs are most effected
Main species affected by Blastomyces dermatitidis (blastomycosis)?
- Dogs
Predisposing factors of Malassezia pachydermatis?
- flea allergy, genetic factors
- > NOT a systemic disease
What type of disease is Cryptococcus neoformans?
- airborne infection that forms a capsule
- causes nasal granulomas -> affects the paranasal sinuses
How do you diagnose Cryptococcus neoformans?
- wet mounts (KOH) and culture test
Treatment is antifungal infusion and surgical occlusion of artery to prevent bleeding
- guttural pouch mycosis in horses
These are formed by budding from parent cell
- Blastospores
Zoophilic dermatophytes in cats and dogs
- Microsporum canis
What are fungi resistant to?
- antibacterials/antibiotics such as penicillin
Which species is Cryptococcus neoformans most prevalent in?
- CATS > dogs
Diagnosis of Coccidiodomycosis
- serology
- DTH to coccidoidin
- a skin test
- histopath
What yeast produces enzymes including phospholipases which disrupts host cell membranes and causes granulomas?
- Cryptococcus neoformans
How to treat Candida albicans?
- Nystatin topical, or oral for GI overgrowth
- ketoconazole oral
Mycotic abortion
- in cattle
- caused by aspergillosis fumigatus
- raised cutaneous plaques resembling ring worm lesions
- > impaired circulation
Control of aspergillosis in cattle
- avoid bad hay, silage
Control of aspergillosis in poultry
- litter change
