Respiratory Endemic Fungi

Question 1

Three endemic fungal pathogens

Answer 1

Histoplasmosis
Blastomycosis
Coccidioidomycosis

Question 2

Broad bud neck

Answer 2

Blastomyces dermatitidis/Blastomycosis

Question 3

Incubation time for blastomycosis

Answer 3

4-6 weeks

Question 4

How does Blasto exert it’s virulence?

Answer 4

has surface molecules that bind integrins on host macrophages –> does not necessarily lead to phagocytosis b/c the size of Blasto yeast cell

Question 5

Where is Histo usually found?

Answer 5

Moist, rich soil in temperate climates – South

Question 6

Narrow bud neck

Answer 6

Histoplasma capsulatum & Histoplasmosis

Question 7

What is the primary infection Histo?

Answer 7

Microconidia, because of their small size, become airborne an penetrate into deep lung and deposit in alveoli –> microconidia are then engulfed by macrophages –> convert to yeast form

Question 8

What is the incubation period for Histo?

Answer 8

3-17 days (average of 10 days)

Question 9

What are some of the clinical syndromes associated with Histo?

Answer 9

Pulmonary--can resemble miliary TB on x-ray
Acute pericarditis
Disseminated
Ocular histoplasmosis syndrome
Fibrosing mediastinis

Question 10

Where is coccidioides usually found?

Answer 10

Southwestern US – “Valley fever”

Question 11

What is the morphology of coccidioides?

Answer 11

septate multicellular hyphae with alternate cells developing into barrel-shaped arthroconidia –> In host, arthroconidia convert within 72 hours into large spherules which contain numerous small endospores

Question 12

How does coccidioides present??

Answer 12

7-21 days after exposure as mild flu-like symptoms

Question 13

In what population is a coccidioides infection dangerous for?

Answer 13

Pregnant women

AIDs