Lecture 5: Systemic/Endemic Mycoses Flashcards
Biphasic/dimorphic fungi causing ___
pulmonary +/- systemic disease
what are 3 important systemic/endemic pathogens
- Coccidodes immitis/posadassi
- Blastomyces dermatidis
- Histoplasma capsulatum
what does endemic mean
restricted by geographic location
Coccidiodes immitis and posadassi are more __than dimorphic
biphasic
what structure of coccidiodes immitis forms within host
spherules
what structure of coccidiodes immitis forms within environment
arthroconidia
coccidiodes immitis- identify 1-2
- Spherules
- Arthroconidia
What this structure called and what pathogen
Spherules
Coccidiodes immitis
what are mycelia and hyphae of C. Immitis
alternating barrel shaped arthroscopes/arthroconidia and disjunction cells that facilitate fragmentation
mycelia and hyphae are a saprophytic structure in __
nature
how is C. Immitis transmitted
aerosols, dust storms primary mechanism of aerosolization
t or f: c. Immitis is not communicable
true
what species most common gets C. Immitis
dogs, especially large breeds and humans
what is pathogenesis of C. Immitis
following inhalation exposure of arthroconidia coccidiodes forms spherules
Spherules mature, rupture and can disseminate to other organs
what are some clinical presentations of C. Immitis for healthy and immunocompromised patients
pulmonary infection common- ranges from asymptomatic to severe
Disseminated disease seen in immunocompromised patients- spreads to bones, joints, eyes, GI, skin
how do you dx C. Immitis
- History
- Serology (>25% dogs have titers)
- Sputum and bronchoalveolar lavage: spherules on cytology
- Periodic acid shiff-giant cells with spherules
- Culture
what is tx for C. Immitis
- Triazoles- fluconazole, itraconazole
- Amphotericin B or nikkomycin
how do you prevent/ control C. Immitis
- Recent vaccine trials show promise
- Limit outdoor activity on days following heavy rains/dust storms
- Reduce dust
where is histoplasma capsulatum found in U.S.
eastern u.s. primarily Ohio and Mississippi River valleys
how is H. Capsulatum transmitted
aerosol +/- ingestion of macroconidium
H. Capsulatum are soil dwelling fungi especially soil enriched with __ or __-
bird droppings, bat guano
t or F: histoplasma capsulatum is not horizontally or zoonotically transmissible
true
disseminated disease from H. Capsulatum is seen in ___animals
immunosuppressed
what are some signs of h. Capsulatum in dogs
lack of appetite, diarrhea
how do you dx H. Capsulatum
- Direct microscopic examination of yeast in histologic sections
- PCR
- Culture
- Serology
what is tx for H. Capsulatum
- Itraconazole
- Disseminated disease and chronic pulmonary: itraconazole and amphotericin B
how do you prevent H. Capsulatum
limit exposure to soils contaminated with bird feces
where is blastomyces dermatidis found in environment and U.S.
feces enriched soils around Ohio and Mississippi River valley
what is morphology of blastomyces dermatitis
broad based budding yeast
What pathogen is this
Blastomyces dermatidis
what species is blastomyces dermatidis seen in
dogs, sporting breeds
t or f: blastomyces dermatidis is nontransmissble
true
hematogenous spread of blastomyces dermatidis results in ___
skin, kidney, vertebral/ skeletal and male reproductive lesions, forming granuloma
what is the clinical presentation of blastomyces dermatidis: acute and chronic, and disseminated disease
acute and chronic pulmonary disease
Disseminated disease: skin lesions
what is tx for blastomyces dermatidis
itraconazole, may be combined with amphotericin B
CNS involvement from, blastomyces dermatidis carries __prognosis
poorest
