Lecture 21 11/16/23 Flashcards by Danika Boltz

What are thermally dimorphic fungi?

fungi that are single-celled yeast at body temp, but mold forms at colder environmental temps

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Which yeast species are thermally dimorphic?

-Histoplasma
-Blastomyces
-Coccidioides
-Sporothrix

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What are the characteristics of Blastomyces dermatitidis?

-dimorphic fungus characterized by large, broad-based budding yeast
-endemic to Ohio-Mississippi river valley

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What are the characteristics of blastomycosis?

-spores are inhaled
-common in dogs and humans
-disseminated disease is common
-pyogranulomatous/granulomatous inflammation

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How can Blastomyces sp. be diagnosed?

-direct detection
-biopsy and histopath.
-fungal culture
-serology

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What are the characteristics of Blastomyces treatment and control?

-early recognition important
-treated with amphotericin and/or itraconazole
-no vaccine

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What are the characteristics of Histoplasma capsulatum?

-small, oval yeast
-seen in macrophages
-BSL3
-endemic in Ohio, Missouri, and Mississippi river valleys

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What are the characteristics of histoplasmosis?

-inhalation of fungus
-transmission favored by dry/dusty conditions and soil disturbance
-common in humans, dogs, and cats
-chronic/active resp. disease or disseminated disease
-intestinal disease in dogs
-granulomatous inflammation
-not usually contagious
-granulomatous chorioretinitis in cats

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How are Histoplasma diagnosed?

-microscopic detection
-culture
-serology
-antigen detection

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What is the treatment for Histoplasma?

-azoles
-amphotericin B

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How can Histoplasma be controlled?

reduce airborne spread of droppings and contaminated dust

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What are the characteristics of Coccidioides immitis?

-dimorphic fungus that does not produce a yeast
-produces large, thick-walled spherules containing endospores
-BSL3
-endemic in San Joaquin valley/southwestern US

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What are the characteristics of coccidioidomycosis?

-inhalation of arthroconidia
-transmission favored by dry conditions and soil disturbance
-common in humans, dogs, and horses
-chronic/active resp. and disseminated disease similar to TB
-osteomyelitis

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How is Coccidioides immitis diagnosed?

-direct detection
-culture
-serology
-antigen EIA

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How is Coccidioides immitis treated?

-azoles
-amphotericin B

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How is Coccidioides controlled?

reducing airborne spread of contaminated dust

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What are the characteristics of Sporothrix schenkii?

-cigar-shaped, elongated, pleomorphic yeast
-lives in plant materials and soil
-disease often subcutaneous/restricted to skin and regional lymph nodes
-common in cats and horses

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How is Sporothrix schenkii diagnosed?

-microscopic detection
-culture

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What are the treatments for Sporothrix schenkii?

-azoles
-potassium iodide

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How is Sporothrix schenkii controlled?

minimizing mechanical injuries from reservoir sources

What is Sporothrix brasiliensis?

an emerging fungal infection in humans that results from cat bites and scratches

What are the characteristics of diseases caused by saprophytic filamentous fungi?

-occur in immunocompromised individuals
-can affect most species
-infection can occur throughout the body (many different presentations)

Which fungal diseases fall into the saprophytic filamentous category?

-zygomycosis
-hyalohyphomycosis
-phaeohyphomycosis

What are the characteristics of Aspergillus?

-fast-growing mold
-found everywhere in environment
-can invade damaged tissues along blood vessels

Which disease presentations can Aspergillus be involved in?

-avian resp. infections -canine and equine nasal/sinus/guttural pouch infections -canine and equine keratitis -disseminated aspergillosis in canines -abortions in ruminants -allergic reactions -abscesses

What are the general characteristics of Aspergillus infections?

-occur in immunocompromised individuals and those in poor conditions -inhalation or ingestion entry route -inflammatory response -invasion of blood vessels

What are common presentations of avian aspergillosis/brooder pneumonia?

-air sacculitis -caseous granulomatous pneumonia

What are the characteristics of mycotic rumenitis?

-following rumen acidosis, acid damages mucosa -fungi are resistant to acid and invade mucosa

When does chronic sinusitis occur in dogs, cats, and horses?

following heavy inhalation of molds

What occurs in mycotic keratitis in horses?

corneal abrasion caused by straw allows mold to infect the damaged cornea

Which species are able to cause fungal pneumonia?

Aspergillus sp. and other opportunistic fungi

How are Aspergillus sp. diagnosed?

-direct demonstration -culture -serology

Which treatments are available for Aspergillus sp.?

-amphotericin -itraconazole -surgical removal of granulomatous tissue

How can Aspergillus sp. be controlled?

preventing predisposition

Which fungus causes phaeohyphomycosis in dogs?

Fonsecaea pedrosoi

What are the characteristics of Prototheca?

-achlorophyllous algae -diagnosed through microscopic detection and culture -treated with surgical excision of lesions -control involves avoiding potential enviromental sources

Which diseases are caused by Prototheca zopfii?

-disseminated disease in dogs -mastitis in cattle -cutaneous disease in cats and humans

Which disease is caused by Prototheca wickerhamii?

cutaneous disease in cats and humans

What are the characteristics of Oomycetes/water molds?

-includes Pythium insidiosum and Lagenidium sp. -causes cutaneous and subcutaneous lesions in horses, cats, cattle, and humans -causes GI disease in dogs and cats

How can Pythium insidiosum be diagnosed?

-cytology and direct detection -histopath. -serology -culture

How can Pythium insidiosum be treated/controlled?

-aggressive surgical resection -vaccine available

What are the characteristics of white-nose syndrome?

-disease in hibernating bats -caused by Pseudogymnoascus destructans

What are the characteristics of Chytridiomycosis in amphibians?

-caused by Batrachochytrium dendrobatidis -causes cutaneous disease

What is caused by Rhinosporidium seeberi?

nasal polyps and cutaneous cysts in mammals and birds

What is caused by Pneumocystis carinii?

pneumonia in immunodeficient animals

What is lacaziosis?

fungal infection in dolphins caused by Lacazia loboi

What are mycotoxins?

secondary metabolites produced by fungi that are capable of causing disease and death

What are the major mycotoxins?

-ergot alkaloids -fumonisin -ochratoxin -aflatoxin -zearalenone