Unit 4 - Fungi causing internal (systemic) mycoses

Question 1

Where are Aspergillus species common in?

Answer 1

air, soil, and animal feeds

Question 2

What Aspergillus species is the most common cause of infection?

Answer 2

Aspergillus fumigatus

Question 3

What does Aspergillus cause in cattle?

Answer 3

pulmonary and cutaneous infectino, abortions, rumenitis, gastritis, and mastitis

Question 4

What does Aspergillus cause in horses?

Answer 4

associated with abortion, guttural pouch infection, diarrhea in foals

Question 5

What does Aspergillus cause in dogs?

Answer 5

frontal sinus infection

Question 6

What does Aspergillus cause in cats?

Answer 6

pulmonary disease

Question 7

What does Aspergillus cause in birds?

Answer 7

brooder pneumonia, respiratory disease in captive penguins and commercial poultry, and crop mycosis in commercial turkey flocks

Question 8

What does Aspergillus look like when it grows?

Answer 8

wooly, dense, pigmented green, bluish-green, olive, or yellowish-green

Question 9

What does Aspergillus grow on?

Answer 9

SGA and BAP

Question 10

How is Aspergillus transmitted?

Answer 10

via feed in commercial poultry, inhalation or ingesion of spores

Question 11

How is Aspergillus infection treated in pet birds and raptors?

Answer 11

Miconazole and other imidazole compounds

Question 12

What is the perfect state of Cryptococcus neoformans?

Answer 12

Filobasidiella neoformans in the Basidiomycota along with the mushrooms and toadstools

Question 13

What does Cryptococcus neoformans have a pedilection for?

Answer 13

the brain and meninges

Question 14

What is the natural habitat for Cryptococcus neoformans?

Answer 14

it is clasically associated with dessicated pigeon feces, some trees that have pockets of rotted material

Question 15

How do dogs, cats, and humans get Cryptococcus neoformans infections?

Answer 15

it is readily inhaled and there is usually pulmonary infection

Question 16

If infection by Cryptococcus neoformans in dogs, cats, and humans becomes disseminated, what happens?

Answer 16

meningoencephalitis is the msot common characterization - fever and severe headaches in humans

Question 17

What does Cryptococcus neoformans infect in cattle?

Answer 17

mammary tissue and adjacent lymph nodes

Question 18

What does Cryptococcus neoformans cause in horses?

Answer 18

nasal discharge, respiratory distress due to nasal granuloma formation

Question 19

What do colonies of Cryptococcus neoformans look like?

Answer 19

cream-colored to tan, moist, glassy, mucoid colonies that are typical of yeasts - brown colonies on seed agar

Question 20

What is the morphology of Cryptococcus neoformans?

Answer 20

a heavy mucopolysaccharide capsule surrounds the cells in tissues - the capsule is usually very thin on culture media but very large and impressive when present in smears

Question 21

How is Cryptococcus neoformans diagnosed?

Answer 21

PCR-testine, direct examination with India ink, ID from culture, and serodiagnosis

Question 22

What is the perfect state name for Blastomyces dermatitidis?

Answer 22

Ajellomyces dermatitidis

Question 23

What does Blastomyces dermatitidis cause?

Answer 23

North American blastomycosis, a chronic, granulomatous, and suppurative infectionof humans and domestic animals

Question 24

What is the morphology of Blastomyces dermatitidis?

Answer 24

it is dimorphic

Question 25

When does the yeast phase of Blastomyces dermatitidis occur?

Answer 25

in tissues and at 37 degrees C on rich media

Question 26

What is the yeast phase of Blastomyces dermatitidis characterized as?

Answer 26

thick walled, budding on a broad base and large

Question 27

When is the mycelial phase of Blastomyces dermatitidis present?

Answer 27

on SGA at 25-30 C

Question 28

What is mycelial phase of Blastomyces dermatitidis characterized as?

Answer 28

conidia are borne laterally on conidiophores or terminally on hyphae

Question 29

Where is Blastomyces dermatitidis confined to?

Answer 29

the US and Canada

Question 30

What is the natural habitat of Blastomyces dermatitidis?

Answer 30

moist soil that frequently has a combination of animal feces, insect parts, and high organic matter which is usually moist, shaded from direct sunlight, and has a pH of less than 6

Question 31

What is infection with Blastomyces dermatitidis usually associated with?

Answer 31

activity in low lying areas around reservoirs, dams, and rivers

Question 32

What does Blastomyces dermatitidis usually start as?

Answer 32

pulmonary infection

Question 33

What does the pulmonary infection due to Blastomyces dermatitidis disseminate to?

Answer 33

it disseminates via a hematogenous route and produces granulomatous infection of skin and internal organs

Question 34

What immunity is associated with Blastomyces dermatitidis infection?

Answer 34

cell mediated immunity

Question 35

How do you diagnose a Blastomyces dermatitidis infection?

Answer 35

with typical broad-based budding yeast cells from tracheal wash or histopathology sections

Question 36

How do you treat Blastomyces dermatitidis infections?

Answer 36

Stilbamidine or amphoteracin B, and Ketaconizole

Question 37

What do Coccidioides immitis and Coccidioides posadasii cause?

Answer 37

valley fever and chronic disseminated lesions

Question 38

What is the morphology of Coccidioides immitis and Coccidioides posadasii?

Answer 38

in pus and granulation tissue they appear as spherical bodies or sporangia

Question 39

What do Coccidiodes immitis and Coccidiodes posadasii develop in culture?

Answer 39

hyphae - which are very dangerous for lab workers

Question 40

Where is valley fever endemic?

Answer 40

in the US and San Joaquin Valley of California

Question 41

Where is Coccidiodes immitis confined to?

Answer 41

California and Northern New Mexico

Question 42

Where is Coccidiodes posadasii found?

Answer 42

in CA, TX, AZ, UT, NM, NV, and Central and South America

Question 43

What is the pathogenesis of Valley Fever?

Answer 43

1. Desert rodents excrete large numbers of the spherules in their feces around their burrows. 2. The spores germinate and the fungi multiply in nearby soil after it rains 3. When the ground dries, arthrospores are formed within the hyphae and these are blown about in the dust 4. Animals grazing these areas and dogs sniffing rodent burrows may inhale large numbers of arthrospores

Question 44

What does Coccidiodes immitis and Coccidiodes posadasii cause in cattle and sheep?

Answer 44

it causes benign disease of the lymph nodes of the chest

Question 45

What lesions does Coccidiodes immitis and Coccidiodes posadasii cause in dogs?

Answer 45

granulomatous lesions in the lungs leading to debilitation and death

Question 46

What does Coccidiodes immitis and Coccidiodes posadasii cause in humans?

Answer 46

valley fever - the pulmonary form of infection

Question 47

How is Coccidiodes immitis and Coccidiodes posadasii infection treated?

Answer 47

with Amphotericin B

Question 48

What disease to Histoplasma capsulatum cause and where?

Answer 48

generalized disease involving the liver, spleen, bone marrow, lungs, and other tissues

Question 49

What is the morphology of Histoplasma capsulatum?

Answer 49

dimorhic fungus

Question 50

What is the morphology of Histoplasma capsulatum in tissues and 37 degrees C?

Answer 50

it is round to oval, single or budding yeast cells (can be seen in monocytes but also in PMNs and giant cells)

Question 51

What is the morphology of Histoplasma capsulatum at room temp?

Answer 51

it is typically mold-like mycelial organism at 2-4 weeks with 2 spores - microconidia and tuberculate chlamydospores

Question 52

What does the colony of the mycelial phase of Histoplasma capsulatum?

Answer 52

it is white and cottony but may be quite variable and range from brown to slate gray

Question 53

Where is disease caused by Histoplasma capsulatum endemic to?

Answer 53

the Mississippi and Ohio River valley

Question 54

Where is Histoplasma capsulatum typically isolated from?

Answer 54

soil especially where heavy contamination with bird droppings

Question 55

How is Histoplasma capsulatum transmitted?

Answer 55

inhalation of airborne spores which are then phagocytized and spread to other organs via migrating mononuclear cells

Question 56

What disease is associated with Histoplasma capsulatum?

Answer 56

splenomegaly, hepatomegaly, anemia, emaciation in disseminated disease - CNS, bone marrow, kidneys, and skin may be involved

Question 57

How is Histoplasma capsulatum diagnosed?

Answer 57

via demonstration and growth of the organism from tissues or antigen or antibody detection from urine or blood samples is also performed

Question 58

What is histoplasmin?

Answer 58

a skin test antigen for delayed type hypersensitivity

Question 59

What immunity is associated with Histoplasma capsulatum?

Answer 59

cell mediated immunity

Question 60

How is Histoplasma capsulatum infection treated?

Answer 60

Amphotericin B followed by itraconazole

Question 61

What does Histoplasma capsulatum var farciminosum cause?

Answer 61

epizootic lymphangitis or African farcy in horses and mules

Question 62

What is the morphology of Histoplasma capsulatum in pus?

Answer 62

oval, yeast-like cells

Question 63

Where is Histoplasma capsulatum var farciminosum endemic?

Answer 63

in soil in parts of Africa, the Middle East, and Asia

Question 64

How does Histoplasma capsulatum var farciminosum spread through the body?

Answer 64

It enters via wounds, spreads to the superficial lymphatic vessels and nodes particularily of the legs, chest, and neck

Question 65

What lesion does Histoplasma capsulatum var faciminosum cause?

Answer 65

it cause the lymph nodes and channels to become swollen and rupture - the disease is chronic and progressive

Question 66

How do you treat a Histpolasma capsulatum var farciminosum infection?

Answer 66

with Na Iodide

Question 67

What is Zygomycosis?

Answer 67

a general term used to describe infections caused by the Zygomycetes

Question 68

What lesions are involved with zygomycosis?

Answer 68

granulomatous and ulcerative lesions that involve the lymph nodes, respiratory, and alimentary tracts - the lymph nodes become caseocalcereous

Question 69

What can Zygomycetes cause in cattle?

Answer 69

abortions

Question 70

What do Zygomycetes look like in tissue?

Answer 70

coarse, non-septate, branching hyphae with rounded sporangia at their terminal portion

Question 71

What are the genera of importance to Mucormycosis?

Answer 71

Mucor, Rhizopus, and Absidia

Question 72

What do Mucor colonies look like?

Answer 72

dense, white to gray, cottony growth that tends to fill the tube or plate

Question 73

What is the natural habitat of the Mucor species?

Answer 73

They are all saprophytes and occur widely in nature

Question 74

How do Mucor species infect animals?

Answer 74

via inhalation or ingestion of spores and occasionally by traumatic implantation

Question 75

How do you diagnose Mucor?

Answer 75

find the distinctive broad non-septae hyphae in the tissues

Question 76

What is Chromomycosis?

Answer 76

subcutaneous infections caused by a number of dematiaceous fungi

Question 77

What species get chromomycosis?

Answer 77

dogs, horses, and humans

Question 78

What species (fungi) are involved with chromomycosis?

Answer 78

Hormodendrum, Cladosporium, Curvularia, Phialophora

Question 79

What is the morphology of the organisms that cause Chromomycosis?

Answer 79

single celled or clustered, spherical, thick waled yeast cells, with a dark brown to black pigment

Question 80

What does the culture of Chromomycosis causing species look like?

Answer 80

dark brown or black colonies

Question 81

Where are the organsisms that cause Chromomycosis found?

Answer 81

widespread in nature

Question 82

How do organisms that cause Chromomycosis enter the body?

Answer 82

via wounds or abrasions

Question 83

What lesions does Chromomycosis cause?

Answer 83

produces nodular and frequently ulcerative lesions of the feet and legs with regional granulomatous lymphadenitis

Question 84

What is Mycetoma?

Answer 84

a localized swollen lesion consisting of granulomas and abscesses which suppurate and drain through sinus tracts

Question 85

What parts of the body can get mycetoma?

Answer 85

the skin, subcutaneous tissue, fascia, and bone

Question 86

What are Actinomycotic mycetomas caused by?

Answer 86

species of the genus Actinomyces - not fungal

Question 87

What causes Eumycotic mycetomas?

Answer 87

it is caused by at least 13 different species of fungi

Question 88

What organisms cause Mycetomas?

Answer 88

Allescheria, Curvularia, and Helminthosporium

Question 89

What is the morphology of the fungi that cause Mycetoma look like?

Answer 89

discrete, brown or black fungus embedded in a large mass of granulation tissue