Lecture 21 11/16/23 Flashcards
What are thermally dimorphic fungi?
fungi that are single-celled yeast at body temp, but mold forms at colder environmental temps
Which yeast species are thermally dimorphic?
-Histoplasma
-Blastomyces
-Coccidioides
-Sporothrix
What are the characteristics of Blastomyces dermatitidis?
-dimorphic fungus characterized by large, broad-based budding yeast
-endemic to Ohio-Mississippi river valley
What are the characteristics of blastomycosis?
-spores are inhaled
-common in dogs and humans
-disseminated disease is common
-pyogranulomatous/granulomatous inflammation
How can Blastomyces sp. be diagnosed?
-direct detection
-biopsy and histopath.
-fungal culture
-serology
What are the characteristics of Blastomyces treatment and control?
-early recognition important
-treated with amphotericin and/or itraconazole
-no vaccine
What are the characteristics of Histoplasma capsulatum?
-small, oval yeast
-seen in macrophages
-BSL3
-endemic in Ohio, Missouri, and Mississippi river valleys
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
How are Histoplasma diagnosed?
-microscopic detection
-culture
-serology
-antigen detection
What is the treatment for Histoplasma?
-azoles
-amphotericin B
How can Histoplasma be controlled?
reduce airborne spread of droppings and contaminated dust
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
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
How is Coccidioides immitis diagnosed?
-direct detection
-culture
-serology
-antigen EIA
How is Coccidioides immitis treated?
-azoles
-amphotericin B
How is Coccidioides controlled?
reducing airborne spread of contaminated dust
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
How is Sporothrix schenkii diagnosed?
-microscopic detection
-culture
What are the treatments for Sporothrix schenkii?
-azoles
-potassium iodide
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
