Lecture 5: Systemic/Endemic Mycoses

Question 1

Biphasic/dimorphic fungi causing ___

Answer 1

pulmonary +/- systemic disease

Question 2

what are 3 important systemic/endemic pathogens

Answer 2

1. Coccidodes immitis/posadassi
2. Blastomyces dermatidis
3. Histoplasma capsulatum

Question 3

what does endemic mean

Answer 3

restricted by geographic location

Question 4

Coccidiodes immitis and posadassi are more __than dimorphic

Answer 4

biphasic

Question 5

what structure of coccidiodes immitis forms within host

Answer 5

spherules

Question 6

what structure of coccidiodes immitis forms within environment

Answer 6

arthroconidia

Question 7

coccidiodes immitis- identify 1-2

Answer 7

1. Spherules
2. Arthroconidia

Question 8

What this structure called and what pathogen

Answer 8

Spherules
Coccidiodes immitis

Question 9

what are mycelia and hyphae of C. Immitis

Answer 9

alternating barrel shaped arthroscopes/arthroconidia and disjunction cells that facilitate fragmentation

Question 10

mycelia and hyphae are a saprophytic structure in __

Answer 10

nature

Question 11

how is C. Immitis transmitted

Answer 11

aerosols, dust storms primary mechanism of aerosolization

Question 12

t or f: c. Immitis is not communicable

Answer 12

true

Question 13

what species most common gets C. Immitis

Answer 13

dogs, especially large breeds and humans

Question 14

what is pathogenesis of C. Immitis

Answer 14

following inhalation exposure of arthroconidia coccidiodes forms spherules

Spherules mature, rupture and can disseminate to other organs

Question 15

what are some clinical presentations of C. Immitis for healthy and immunocompromised patients

Answer 15

pulmonary infection common- ranges from asymptomatic to severe

Disseminated disease seen in immunocompromised patients- spreads to bones, joints, eyes, GI, skin

Question 16

how do you dx C. Immitis

Answer 16

1. History
2. Serology (>25% dogs have titers)
3. Sputum and bronchoalveolar lavage: spherules on cytology
4. Periodic acid shiff-giant cells with spherules
5. Culture

Question 17

what is tx for C. Immitis

Answer 17

1. Triazoles- fluconazole, itraconazole
2. Amphotericin B or nikkomycin

Question 18

how do you prevent/ control C. Immitis

Answer 18

1. Recent vaccine trials show promise
2. Limit outdoor activity on days following heavy rains/dust storms
3. Reduce dust

Question 19

where is histoplasma capsulatum found in U.S.

Answer 19

eastern u.s. primarily Ohio and Mississippi River valleys

Question 20

how is H. Capsulatum transmitted

Answer 20

aerosol +/- ingestion of macroconidium

Question 21

H. Capsulatum are soil dwelling fungi especially soil enriched with __ or __-

Answer 21

bird droppings, bat guano

Question 22

t or F: histoplasma capsulatum is not horizontally or zoonotically transmissible

Answer 22

true

Question 23

disseminated disease from H. Capsulatum is seen in ___animals

Answer 23

immunosuppressed

Question 24

what are some signs of h. Capsulatum in dogs

Answer 24

lack of appetite, diarrhea

Question 25

how do you dx H. Capsulatum

Answer 25

1. Direct microscopic examination of yeast in histologic sections 2. PCR 3. Culture 4. Serology

Question 26

what is tx for H. Capsulatum

Answer 26

1. Itraconazole 2. Disseminated disease and chronic pulmonary: itraconazole and amphotericin B

Question 27

how do you prevent H. Capsulatum

Answer 27

limit exposure to soils contaminated with bird feces

Question 28

where is blastomyces dermatidis found in environment and U.S.

Answer 28

feces enriched soils around Ohio and Mississippi River valley

Question 29

what is morphology of blastomyces dermatitis

Answer 29

broad based budding yeast

Question 30

What pathogen is this

Answer 30

Blastomyces dermatidis

Question 31

what species is blastomyces dermatidis seen in

Answer 31

dogs, sporting breeds

Question 32

t or f: blastomyces dermatidis is nontransmissble

Answer 32

true

Question 33

hematogenous spread of blastomyces dermatidis results in ___

Answer 33

skin, kidney, vertebral/ skeletal and male reproductive lesions, forming granuloma

Question 34

what is the clinical presentation of blastomyces dermatidis: acute and chronic, and disseminated disease

Answer 34

acute and chronic pulmonary disease Disseminated disease: skin lesions

Question 35

what is tx for blastomyces dermatidis

Answer 35

itraconazole, may be combined with amphotericin B

Question 36

CNS involvement from, blastomyces dermatidis carries __prognosis

Answer 36

poorest