mycology part 2

Question 1

opportunistic mycoses

Answer 1

candida albicans

aspergillus fumigatus

pseudoallescheria boydii

cryptococcus neoformans

dematiaceous fungi (pigmented fungi)

Question 2

aspergillus fumigatus

Answer 2

mold form fungus

uniquitous in environment

grows very rapidly

a common contaminant of fungal cultures

can create mycetomas (fungal masses)

canine nasal aspergillosis

Question 2

candidiasis

Answer 2

usually ALBICANS

always a yeast form (no mold)

normal flora of animals (lowkey everwhere), kept in check by normal microbiome

causes mucosal infections (thrush, bladder UTI, sour crop in birds)

Question 3

candida as fungal cystitis/pyelonephritis

Answer 3

can turn into an ascending infection

Question 4

mycotic abortion in cattle

Answer 4

asperfillus fumigatus

mucor

likely related to quality of hay or silage

Question 4

mycetomas (fungal masses)

Answer 4

usually A. fumigatus

immunosuppression

NOT required for LOCALIZED disease

EX. guttural pouch mycosis

Question 5

pseudallesheria boydii

Answer 5

ALSO causes canine nasal masses -
fungal differential for canine nasal aspergillosis

cows: granulomatous rhinitis and sinusitis

Question 5

mycotic keratitis

Answer 5

horses, dogs

spores invade via corneal injury
- aspergillus
- fusarium
- alternaria

diagnosis via cytology or culture

Question 6

cryptococcosis

Answer 6

cytptococcus neoformans
- ubiquitous in environment
- enriched by pigeon droppings

cytpococcus gattii
- associated with eucalyptus and douglas fir

Question 7

cryptococcus spp.

Answer 7

yeast form - small spore with a huge capsule = very recognizable

will cause disease if/when
- very high inoculum
- immunosuppression

will cause disease in:
- cats (ESP)
-dogs
- humans
- rarely in horeses (gattii in PNW)

Question 8

cryptococcosis treatment

Answer 8

manage underlying immunosuppressive disease
- FeLV and FIV (chances of successful tx slim), decrease chance for successful tx

intraconazole, fluconazole
- months to years

monitor therapy with antigen detection

Question 8

cryptococcosis pathogenesis

Answer 8

penetrates respiratory epithelium

replicates in and replaces host tissue

inflammatory response initiated: minimal in immunocompromised individuals, granulomas form in healthy

tropism for cooler tissues (Resp. tract, skin), but also CNS and eye
- CAN go to brain

Question 8

cryptococcosis dx

Answer 8

cytology - indica ink

hisopathology

culture

antigen detection in serum
- latex agglutination
- enzyme immunoassay

Question 9

pathogenic systemic mycoses

Answer 9

immunosuppression is NOT required

have distinct geographic distributions

blastomyces dermatitidis

histoplasma capsulatum

coccidiodes immitis

Question 10

blastomycosis pathogenesis

Answer 10

inhalation of spores from mold
- transform to yeast in vivo

initial infection is usually pulmonary

can disseminate to: bone, CNS/eye, skin

pyogranulomatous inflammation

Question 10

blasomycosis

Answer 10

eastern and midwestern US
- acidic, moist soils

causes disease in dogs and humans
- rare in other species
- not seen at all in cattle

thermally dimorphic
- mold at 25ºC (infectious form)
- yeast at body temp (Broad based budding)

often misdiagnosed

Question 11

geographic distributions of system mycoses in US

Answer 11

blasomycosis south east

histoplasmosis mid west

coccidiodomycosis - south west and central

Question 12

blastomyces dermatitidis

Answer 12

insidious onset of disease

enhanced by corticosteroid administration

dx can be challenging
- histopathology
- cytology/LN aspiration
- culture
- serology (AGID for anti-blasto antibodies)
- detectioon of galactomannan antigen in urine

Question 13

blastomyces in the lab

Answer 13

identified by culture

brain-heart infusion (BHI) agar with cycloheximide and chloramphenicol

incubate at room temperature

don’t casually take the lid off the dish!!!

Question 14

blastomycosis tx

Answer 14

systemic antifungals for 2-3 months
- amphotercin B
- intraconazole
- fluconazole

recurrence rate is 25%!
- success after recurrence is about 80%

Question 15

histoplasma capsulatum

Answer 15

bat:) and bird droppings

causes dz in cats, dogs, and humans

midwest and south central US
- esp Ohio and Mississippi river valleys

thermally dimorphic

not zoonotic

Question 16

h. capsulatum pathogenesis

Answer 16

inhalation of mold spores - pulmonary lesions

disseminates to: small intestine, liver, LNs, spleen, eye, bone

may present as wasting disease due to malabsorption

Question 17

histoplasmosis diagnosis

Answer 17

cytology
-ultrasound guided needle aspiration

histopathology

culture 10-60 days

serology, but unreliable

urine antigen test

Question 18

histoplasmosis tx

Answer 18

systemic antifungals
- azoles 4-6 mos

ancillary/supportive
- glucocorticoids in dogs with hilar lymphadenopathy
-controversial because of immunosuppresion

Question 19

coccidiodes immitis

Answer 19

think DESERT - lower sonoran life zones, alkaline soil - SW US, pockets in CA< WA valley fever - dogs -cats (rare) - horses (rare) - camelids tissue dimorphism - NOT temperature dependent

Question 20

c. immitis pathogenesis

Answer 20

breath in arthroconidia lung infection in terminal bronchiole contact with alveolar epithelium septation endospourulation and release osteomyelitis, local swelling and drainage

Question 21

coccidiomycosis gross signs

Answer 21

severe hilar LN enlargement multifocal granulomas in lungs osteomyelitits

Question 22

C. immitis morphology

Answer 22

arthrospores spherule containing endospores

Question 22

coccidiomycosis dx

Answer 22

cytology histopathology culture - 3-10days serology: wide variety of tests to detect antibodies

Question 23

coccidiodomycosis tx

Answer 23

treat 3-6 mos BEYOND resolution of clinical signs - azoles - amphotercin B stop at glucocorticoids relapses are possible variable prognosis - pulmonary only > disseminated > osteomyelitis

Question 24

coccidiodomycosis zoonotic potential

Answer 24

no spread to human from animal documented not considered zoonotic BUT bandages draining tracts could be a problem -mycelia can grow in bandage humans can get it from the environment soooo...