Respiratory Fungi

Question 1

What are the features of fungi seen grossly/histologically? (Slides 4 to 8) (10)

Answer 1

• Hyphae (filaments)
• Yeasts
• Septate = divisions
• Non-spetate
• Budding - new yeast forming off original yeast + going externally (outside)
• Endosporulation - bigger cyst w/ little yeasts budding inside the same structure and enlarging into the centre
• Broad-based budding
• Narrow-based budding
• Pigmented
• Non-pigmented - purple background from H&E stain

Question 2

What is Aspergillus fumigatus and what diseases does it cause? (3)

Answer 2

• Ubiquitous environmental fungus, factors predisposing to disease following inhalation are not clear (immunosuppression not usually a factor)
• Mycotic rhinitis
• Pulmonary aspergillosis

Question 3

What is mycotic rhinitis? (6)

Answer 3

Question 4

Mycotic rhinitis - diagnosis and gross pathology (5)

Answer 4

Question 5

How does Aspergillus fumigatus appear histologically?

Answer 5

Question 6

What is pulmonary aspergillosis (2)

Answer 6

Question 7

What is Blastomyces dermatitidis? (2)

Answer 7

• Thermally dimorphic fungus - infectious, noncontagious disease of dogs and humans, reported in cats, horses, ferrets, less common in other species
• Primarily in North America, especially river valleys and Great Lakes basin, sporadic occurrences elsewhere

Question 8

Blastomyces dermatitidis pathogenesis (6)

Answer 8

Question 9

Blastomyces dermatitidis - gross pathology and differentials (3)

Answer 9

Question 10

Blastomyces dermatitidis disseminated lesions (4)

Answer 10

Question 11

Blastomyces dermatitidis - diagnosis (4)

Answer 11

Question 12

What is cryptococcosis and what lesions does it produce? (4)

Answer 12

Question 13

Cryptococcus pathogenesis (5)

Answer 13

Question 14

What is cryptococcus neoformans? (2)

Answer 14

• Temperate climates, found in soil and bird droppings
• Most common in dogs, usually requires immunosuppression for lesions

Question 15

What is cryptococcus gatti? (2)

Answer 15

• Formerly considered tropical but now wider distribution including Pacific Northwest
• Most common in cats, causes disease in immunocompetent animals

Question 16

Cryptococcosis - diagnosis (3)

Answer 16

Question 17

What is Coccidioidomycosis (Valley Fever) (5)

Answer 17

Question 18

Coccidioidomycosis pathogenesis and diagnosis (4)

Answer 18

Question 19

Coccidioidomycosis - lesions (4)

Answer 19

Question 20

What is Pneumocystis carinii and its pathogenesis? (6)

Answer 20

Question 21

Pneumocystis carinii - histopathology (4)

Answer 21

Question 22

Pneumocystis carinii - gross pathology and diagnosis (3)

Answer 22

Question 23

What is Entomopthoromycosis? (3)

Answer 23

Question 24

Entomopthoromycosis - lesions and differentials (5)

Answer 24

Question 25

Entomopthoromycosis - pathogenesis (4)

Answer 25

Question 26

What is Pythium insidiosum (3)

Answer 26

Question 27

What is Rhinosporodoum seeberi and the gross lesions it produces? (4)

Answer 27

Question 28

What is Mortierella wolfi? (4)

Answer 28

* In cows * Acute fatal mycotic pneumonia secondary to placental infection * Fibrinonecrotic pneumonia within a few days of parturition or abortion, due to haematogenous spread as the placenta detaches (embolic pattern in lungs) * Rare outside New Zealand

Question 29

What is Emmonsia sp. (5)

Answer 29

* Adiasporomycosis, mostly wild rodents but sometimes domestic animals * Dimorphic fungus related to blastomycosis * Granulomatous lesions in lungs, sometimes lymph nodes * Diagnosed by finding large (300 μm), spherical, uninucleate adiaspores * Thick PAS-positive wall (magenta satining), does not endosporulate

Question 30

Which other fungi can be occasional opportunists in cows? (2)

Answer 30

Mucor and Rhizopus sp. - cause caseous necrosis or granulomatous inflammation

Question 31

What is Histoplasma capsulatum?

Answer 31

Can cause pulmonary lesions, found in contaminated soil

Question 32

What can cause a granulomatous reaction in dogs?

Answer 32

When they inhale spores from puffball mushrooms (just foreign bodies, not infectious so no inflammation associated)