Blastomyces, Coccidioides, Histoplasma, Cryptococcus Flashcards
What disease patterns are seen in cryptococcosis?
Mycotic rhinitis (sneezing, nasal discharge, nasal granuloma)
May cause cutaneous or ocular lesions and menigitis
What is the morphology of Cryptococcus neoformans?
(mold, yeast, dimorphic)
Yeast
How is cryptococcosis treated?
Which antifungal is not typically used?
Fluconazole
Usually amphotericin B is not used because C. neoformans is less likely to become systemic
What is the primary manifestation of coccidioidomycosis in dogs?
What other diseases can occur?
Primary pulmonary infection
20% of dogs can have disseminated disease- weight loss, lameness, abscesses, lymphadenopathy, menigitis, etc.
How is histoplasmosis diagnosed?
Examination of a stained buffy coat or smear
What structures will be seen in histology preparations from patients with coccidioidomycosis?
Sporangia (contain yeast cells)
Which species are susceptible to blastomycosis?
Dogs, humans, and cats
Incidence in dogs ten times as high as incidence in humans
What species is most frequently diagnosed with histoplasmosis?
What other species can be affected?
Dogs most frequently diagnosed
Other species- birds, cats, horses, pigs, cattle
Describe the appearance of Blastomyces dermatitidis in a stained aspirate or tissue impression.
Thick walled yeast cells that have single buds attached to mother cells by a broad base
(think _B_lastomyces broad base)
Where is Cryptococcus neoformans endemic in North America?
California and the Pacific northwest
Describe the appearance of Cryptococcus neoformans in histologic preparations.
Cells that have a thick wall that does not stain
What is the treatment for coccidioidomycosis?
Ketoconazole, itraconazole, or amphotericin B
True or false:
Systemic mycoses mostly affect only immunocompromised humans or animals.
False. Fungi that cause systemic infection are inherently virulent and cause diease in healthy humans and animals.
What are potential disease manifestations can blastomycosis take?
Cutaneous, opthalmic, or disseminated
True or false:
FIV+ cats are no more suscepible to cryptococcosis than healthy cats.
True. FIV status does not affect response to treatment either.
True or false:
Amphotericin B is the first choice antifungal drug to treat systemic mycoses.
False. It is the most likely to be toxic to the patient and is used when the prognosis is poor and the potential benefits outweigh the risks.
Where is Blastomyces dermatitidis endemic in North America? Why?
Endemic in the eastern US
Does best in a moist, temperate environment
Fungi that cause systemic mycoses often have what morphology?
Dimorphic (mold form in environment, yeast form in the body)
In what species is cryptococcosis common?
Is it limited to that species?
Common in cats but can infect other mammals
(think cat is crypto)
Should owners whose dogs are diagnosed with blastomycosis be concerned about contracting it from their dog?
Yes and no. They may have been exposed when their dog was, but they are not at risk of directly contracting it from their dog.
What is the treatment for histoplasmosis?
Ketoconazole, itraconazole, or amphotericin B
What is the primary site of infection in cryptococcosis?
The nasal cavity
Where is Histoplasmosis capsulatum endemic in North America?
What are potential sources of infection?
Endemic along the watersheds for the Mississippi and Ohio Rivers
Can be found in warm, wet soil and bird and bat guano
What is the treatment for blastomycosis?
Ketoconazole or amphotericin B
Where is Coccidioidomycosis immitis endemic in North America? Why?
Endemic in the southwestern US (Arizona and New Mexico)
Also found in south/central South America
Does best in an arid, hot climate
How is cryptococcus diagnosed?
Examination of stained exudate from nose, buffy coat or CSF smear, or bronchoaveolar (BAL) wash
Other than dogs, what species are susceptible to coccidioidomycosis?
Humans (flu-like illness, severe pnumonia, disseminated forms)
Horses and llamas
Self-limiting infection in cattle
How do humans and animals contract systemic mycoses?
What is usually the first body system infected?
They inhale spores from the environment
Respiratory system and lungs are the first infected
What is the infectious dose needed to cause coccidioidomycosis?
One inhaled spore
