Mycology

Question 1

Important component in fungal cytoplasmic membranes that is a target for antifungals

Answer 1

ergosterol

Question 2

Basset hound, cocker spaniels, poodles, and west highland terriers are predisposed to infection with what yeast?

Answer 2

Malassezia

Question 3

Associated with greasy lesions that are malordorous and pruritic

Answer 3

Malassezia pachydermatis

Question 4

Prolonged/excessive antimicrobial therapy can predispose for these infections

Answer 4

Candidiasis

Aspergillosis

Question 5

Associated with moist lesions that can be scabbed; “Bed sores”

Answer 5

candida albicans

Question 6

Which of the cutaneous mycoses can disseminate?

Answer 6

Candida albicans

Question 7

How can you confirm invasion by Candida albican?

Answer 7

microscope exam–>presence of pseudohyphae

isolation alone isn’t enough to confirm diagnosis

Question 8

Organisms that most commonly cause dermatophytosis

Answer 8

Microsporum spp. (usually M. canis)

Trichophyton spp.

Question 9

What type of cells are infected by Microsporum/Trichophyton

Answer 9

dead skin cells (i.e. stratum corneum, hair, claw)

Question 10

T/F: Geophilic dermatophytosis can be transferred from dog to man

Answer 10

False; can affect both dog and man but they can only get it from soil

Question 11

Infective portion of Microsporum/Trichophyton

Answer 11

arthroconidia

Question 12

Where do horses usually get ring worm

Answer 12

in friction area (i.e. halter area)

Question 13

Pseudomycetomas associated with dermatophytosis are common to which spp.? Prognosis?

Answer 13

Cats

Poor (needs surgery)

Question 14

Onchomycosis?

Answer 14

infection of the nail/claw

Question 15

Best way to diagnose dermatophytosis?

Answer 15

Culture! Most definitive and can be done in-house

Question 16

Dermatophilosis is caused by a _______

Answer 16

gram positive bacteria

Question 17

Dermatophilus zoospores are attracted to what

Answer 17

differing levels of CO2

Question 18

“Paint brush lesions” are typical of infection with

Answer 18

Dermatophilus

Question 19

Diagnostic feature of Dermatophilus?

Answer 19

double rows of spores!

Question 20

Important virulence factors of aspergillus

Answer 20

aflatoxins

gliotoxins–immunosuppressant

Question 21

In dogs, this disease can present as a respiratory disease with bloody discharge and necrosis of sinuses

Answer 21

Aspergillosis

Question 22

Female german sherpherds are predisposed to what

Answer 22

disseminated aspergillosis

Question 23

Does disseminated aspergillosis in dogs have nasal involvement?

Answer 23

not usually

Question 24

This infection in cattle can cause a respiratory tract infection with abortion; there will be TB-like lesions on the placenta

Answer 24

Aspergillosis

Question 25

Horses infected with _____ with usually have guttural pouch infection and keratitis

Answer 25

Aspergillosis

Question 26

Though rare in cats, which breed is more commonly infected with Aspergillosis

Answer 26

Persians

Question 27

Sino-orbital disease in cats is associated with

Answer 27

Aspergillosis

Question 28

A microscopic exam of a sample containing Aspergillosis will show

Answer 28

septate hyphae | dichotomous branching

Question 29

Which diagnostic tool is least useful for aspergillosis?

Answer 29

serology - -many strains - -host may not be making markers

Question 30

Causative agents of Entomophthoramycosis and their primary mode of tramission

Answer 30

Basidiobolus spp. (percutaneous and ingestion) Conidiobolus spp. (inhalation)

Question 31

Ruminants and small ruminant presenting with a blocked nasal cavity are likely infected with

Answer 31

Conidiobolus

Question 32

This fungus is usually associated with insect bites and rarely disseminates

Answer 32

Basidiobolus

Question 33

When diagnosing Entomophthoramycosis, what should you not do with the sample

Answer 33

refrigerate (they don't like cold)

Question 34

On a microscope, this will present as gram positive branching filaments

Answer 34

Norcardia spp. (Nocardiosis)

Question 35

3 disease forms of Nocardiosis

Answer 35

cutaneous to subcutaneous pulmonary systemic

Question 36

A cow that presents with watery milk that contain white/yellow flakes and has an enlarged udder with nodules most likely has

Answer 36

Nocardiosis

Question 37

Why isn't systemic therapy enough to treat nocardiosis

Answer 37

they are intracellular

Question 38

Unique feature of dematiaceous fungi?

Answer 38

contain melanin in cell wall

Question 39

A dog presenting with a tumor-like lesion with draining tracts and granules. Granules on evaluation are a mixture of necrotic debris and hyphae (with brown pigment). Dx?

Answer 39

Mycetoma

Question 40

Chromoblastomycosis produces what unique feature?

Answer 40

sclerotic bodies

Question 41

Dimorphic fungi are usually ________ dependent

Answer 41

temperature

Question 42

Name the 5 systemic mycoses

Answer 42

``` Blastomyces Histoplasma Crytpococcus Sporothrix Coccidioides ```

Question 43

Most commonly infected host of blastomycosis

Answer 43

dogs

Question 44

An outdoor dog presents with harsh lung sounds, proliferative granulomatous lesions, chronic cough, and weight loss. Radiographs reveal a "snowstorm" appearance to the lungs. Likely Dx?

Answer 44

blastomycosis

Question 45

Best way to diagnose blastomycosis? How will it look?

Answer 45

Microscope exam | broad-based budding yeast (diff-quick)

Question 46

T/F: culture for blastomycosis is easy and can be done in house

Answer 46

False... IT'S VERY DANGEROUS

Question 47

this fungus prefers dark locations and lives in close association with bird and bat excrement

Answer 47

histoplasma

Question 48

Incubation period for histoplasma?

Answer 48

short (12-16 days)

Question 49

Infection of the lower respiratory tract is more likely if this form of histoplasma is inhaled

Answer 49

microconidia (vs. macroconidia)

Question 50

Where does histoplama replicate?

Answer 50

intracellularly ("halo" appearance)

Question 51

A dog presents with weepy, ulcerative lesions, as well as large bowel diarrhea (mucous and blood). Likely Dx?

Answer 51

(based on GI involvement) | histoplasma

Question 52

Why isn't serology very useful for histoplasma?

Answer 52

can get false positive and negatives | also shares antigens with blasto (can be positive for both)

Question 53

Which dimorphic mold is capsulated?

Answer 53

Cryptococcus

Question 54

Cryptococcus favors what form?

Answer 54

yeast

Question 55

Size of the capsule of cryptococcus determines what

Answer 55

if it will stay in the nasal cavity or reach the pulmonary tissue

Question 56

3 important things cryptococcus's capsule does in the host

Answer 56

interferes with leukocyte migration depletes complement inhibits t-cell response

Question 57

Which spp. is most susceptible to cryptococcus

Answer 57

Cats

Question 58

A dog presents with skin lesions, fever, and neurological signs. The CNS signs point to a potential cervical lesion, but based on the other clinical signs, it's probably

Answer 58

cryptococcus

Question 59

A use for serology with cryptococcus infections?

Answer 59

monitoring response to treatment (one dilution drop per month of treatment)

Question 60

Sporothrix is usually found where

Answer 60

in moss and decaying matter

Question 61

the mold form of sporothrix produces conidia that usually enter the host _________

Answer 61

cutaneously (but can also be inhaled)

Question 62

Unique feature of Sporothrix?

Answer 62

Both the mold and yeast forms are infective

Question 63

a cat presents with multiple lesions that have shallow ulcers and draining tracts; most notably the lesions are found mostly on mucosal surfaces (i.e. eye, nose, genitalia). Likely cause?

Answer 63

Sporothrix

Question 64

Sporothrix rarely disseminates in what spp.

Answer 64

dogs (usually localized to nose and extremities)

Question 65

A horse presents with lesions on the medial portion of the fetlock and up; the horse has access to the woods; you also are able to palpate the lymph nodes and feel cording of the lymphatics. that's diagnostic for

Answer 65

Sporothrix

Question 66

Coccidioides is endemic to the

Answer 66

southwest

Question 67

What causes activation of Coccidioides in the host

Answer 67

the CO2 content

Question 68

Dissemination with this organism can be rapid (10 days)

Answer 68

Coccidioides

Question 69

Which dog breeds are more susceptible to dissemination with Coccidioides

Answer 69

boxers and doberman pinschers

Question 70

Finding spherules with a KOH wet mount is diagnostic for

Answer 70

Coccidioides

Question 71

This presents as a tumor-like polyp in the nasal cavity and grow so large it can occlude the airway

Answer 71

rhinosporidium

Question 72

What is the only way to diagnose rhinosporidium

Answer 72

microscope (will not grow in lab)

Question 73

Spp. most commonly infected with rhinosporidium

Answer 73

dogs and horses (rarely cats)

Question 74

This organism is associated with slow moving water and has a tropism for well-vascularized tissues

Answer 74

Prototheca

Question 75

T/F: hosts MUST be immuncompromised to be infected with prototheca?

Answer 75

True

Question 76

An aquatic pathogen that can cause cutaneous or intestinal infarctions

Answer 76

Pythium

Question 77

How is phythium different from fungus?

Answer 77

cell wall doesn't contain ergosterol

Question 78

Pythium is attracted to what types of tissue

Answer 78

damaged (plant or mammal)

Question 79

A dog presents with lesions on his extremities and ventral abdomen; he is EXTREMELY pruritic; the owners says the lesions have tripled in size over the past week... Dx?

Answer 79

Pythium

Question 80

Unique features that can be used to ID pythium with a microscope

Answer 80

1) irregular, random hyphae 2) will not stain with H&E 3) eosinophilic cuff

Question 81

Kunkers are associated with infection with what organism?

Answer 81

Phythium insidiosum

Question 82

This organism has broad, relatively nonseptate hyphae and will stain with H&E

Answer 82

Langenidium