Blastomyces, Coccidioides, Histoplasma, Cryptococcus

Question 1

What disease patterns are seen in cryptococcosis?

Answer 1

Mycotic rhinitis (sneezing, nasal discharge, nasal granuloma)

May cause cutaneous or ocular lesions and menigitis

Question 2

What is the morphology of Cryptococcus neoformans?

(mold, yeast, dimorphic)

Answer 2

Yeast

Question 3

How is cryptococcosis treated?

Which antifungal is not typically used?

Answer 3

Fluconazole

Usually amphotericin B is not used because C. neoformans is less likely to become systemic

Question 4

What is the primary manifestation of coccidioidomycosis in dogs?

What other diseases can occur?

Answer 4

Primary pulmonary infection

20% of dogs can have disseminated disease- weight loss, lameness, abscesses, lymphadenopathy, menigitis, etc.

Question 5

How is histoplasmosis diagnosed?

Answer 5

Examination of a stained buffy coat or smear

Question 6

What structures will be seen in histology preparations from patients with coccidioidomycosis?

Answer 6

Sporangia (contain yeast cells)

Question 7

Which species are susceptible to blastomycosis?

Answer 7

Dogs, humans, and cats

Incidence in dogs ten times as high as incidence in humans

Question 8

What species is most frequently diagnosed with histoplasmosis?

What other species can be affected?

Answer 8

Dogs most frequently diagnosed

Other species- birds, cats, horses, pigs, cattle

Question 9

Describe the appearance of Blastomyces dermatitidis in a stained aspirate or tissue impression.

Answer 9

Thick walled yeast cells that have single buds attached to mother cells by a broad base

(think _B_lastomyces broad base)

Question 10

Where is Cryptococcus neoformans endemic in North America?

Answer 10

California and the Pacific northwest

Question 11

Describe the appearance of Cryptococcus neoformans in histologic preparations.

Answer 11

Cells that have a thick wall that does not stain

Question 12

What is the treatment for coccidioidomycosis?

Answer 12

Ketoconazole, itraconazole, or amphotericin B

Question 13

True or false:

Systemic mycoses mostly affect only immunocompromised humans or animals.

Answer 13

False. Fungi that cause systemic infection are inherently virulent and cause diease in healthy humans and animals.

Question 14

What are potential disease manifestations can blastomycosis take?

Answer 14

Cutaneous, opthalmic, or disseminated

Question 15

True or false:

FIV+ cats are no more suscepible to cryptococcosis than healthy cats.

Answer 15

True. FIV status does not affect response to treatment either.

Question 16

True or false:

Amphotericin B is the first choice antifungal drug to treat systemic mycoses.

Answer 16

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.

Question 17

Where is Blastomyces dermatitidis endemic in North America? Why?

Answer 17

Endemic in the eastern US

Does best in a moist, temperate environment

Question 18

Fungi that cause systemic mycoses often have what morphology?

Answer 18

Dimorphic (mold form in environment, yeast form in the body)

Question 19

In what species is cryptococcosis common?

Is it limited to that species?

Answer 19

Common in cats but can infect other mammals

(think cat is crypto)

Question 20

Should owners whose dogs are diagnosed with blastomycosis be concerned about contracting it from their dog?

Answer 20

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.

Question 21

What is the treatment for histoplasmosis?

Answer 21

Ketoconazole, itraconazole, or amphotericin B

Question 22

What is the primary site of infection in cryptococcosis?

Answer 22

The nasal cavity

Question 23

Where is Histoplasmosis capsulatum endemic in North America?

What are potential sources of infection?

Answer 23

Endemic along the watersheds for the Mississippi and Ohio Rivers

Can be found in warm, wet soil and bird and bat guano

Question 24

What is the treatment for blastomycosis?

Answer 24

Ketoconazole or amphotericin B

Question 25

Where is Coccidioidomycosis immitis endemic in North America? Why?

Answer 25

Endemic in the southwestern US (Arizona and New Mexico)

Also found in south/central South America

Does best in an arid, hot climate

Question 26

How is cryptococcus diagnosed?

Answer 26

Examination of stained exudate from nose, buffy coat or CSF smear, or bronchoaveolar (BAL) wash

Question 27

Other than dogs, what species are susceptible to coccidioidomycosis?

Answer 27

Humans (flu-like illness, severe pnumonia, disseminated forms)

Horses and llamas

Self-limiting infection in cattle

Question 28

How do humans and animals contract systemic mycoses?

What is usually the first body system infected?

Answer 28

They inhale spores from the environment

Respiratory system and lungs are the first infected

Question 29

What is the infectious dose needed to cause coccidioidomycosis?

Answer 29

One inhaled spore