Mycology 5

Systemic mycoses is inherently ____ and primary focus of infection is the ___

virulent

lung

T/F •Each species has biochemical and structural features that enable it to evade host defenses

True

Identified by their morphology on agar plates (___ phase) and in tissue (___ phase)

saprobic

parasitic

What are the TWO forms of Dimorphic Fungi?

Mold

Yeast

____ – Saprophytic form in nature

____ – Parasitic form in host tissue

Mold

Yeast

Dimorphic Fungi are ____ dependent ____ dimorphism

temperature

thermal

What are the FIVE fungi that can cause Systemic mycoses?

1. Blastomyces dermatitidis

2. Histoplasma capsulatum

3. Cryptococcus neoformans

4. Sporothrix schenckii

5. Coccidioides immitis

What spp of Blastomycosis causes chronic pyogranulomatous to granulomatous lesions?

Blastomyces dermatitidis

What species is it most common to see Blastomycosis in?

Dogs and humans

T/F Blastomycosis is an endemic in areas of the Eastern US

True

T/F Environmental or soil organism-favors moist soil and decomposing plant matter such as wood or leaves

True

Where in the US will you typically find blasto?

Mississippi, Missouri, & Ohio river valleys. Likes sandy, acid soil, near water

How does one get infected with Blastomycosis?

Inhalation of conidia in the environment

T/F W/n host, transform into yeasts that can resist destruction by neutrophils. Chronic granulomatous lesions in lung which may spread

True

____ spread from lungs to lymph nodes & other extrapulmonary sites

Hematogenous

How would you describe blastomycosis on morphological features?

Yeast are thick-walled, 8 to 12 um in diameter & produce buds w/ broad-bases, cell walls are refractile and bud enlarges to equal size of parent cell

With blastomycosis, Cell wall components allow it to adhere to ____ and/or impair complement.

macrophages

_____` cell walls and bud enlarges to equal size of mother cell.

refratile

Blastomycosis in dogs: ____ adult, ____ sporting breeds, 1 -5 years of age, ____ higher rate of exposure

young

large

males

What are the clinical signs of blastomycosis in dogs? (8)

fever, anorexia, weight loss, cough, dyspnea, ocular disease, lameness, or skin lesions

T/F 85% have lung lesions w/ dry, harsh lung sounds

True

What is the name of the radiograph that is seen with blastomycosis?

Snowstorm radiograph

Blastomycosis typically has 50% ___ ____ involvement & skin lesions

lymph node

•Blastomycosis should be considered in dogs w/ draining cutaneous nodules & signs of _____ ___

respiratory disease

How does dissemination occur?

vascular and lymphatic routes

Cutaneous and subcutaneous Blastomycosis lesions are frequently found on what THREE parts of the body?

trunk, limbs, and digits

T/F Blastomycosis can cause lameness due to osteomyelitis

True

If a dog is infected with blastomycosis in the nasal cavity, what could occur? (3)

harsh, noisy respiration, decreased nasal airflow, or nasal discharge.

T/F •Up to 40% may have ocular lesions such as uveitis, corneal edema, iritis, retinis, retinal detachment, optic neuritis, secondary glaucoma, or blindness

True

uveitis with in combo with what TWO thinsg can be suggestive of blastomycosis?

respiratory or skin disease

Poorest prognosis is seen with what type of prognosis?

CNS involvement

T/F Blastomycosis is very common in cats

False, uncommon

Cats with blastomycosis typically present in what TWO ways?

exhibit CNS disease & develop large dermal abscesses.

Blastomycosis as with ____ and ____, can occur in cats that have been housed entirely indoors

histoplasmosis

cryptococcosis

How does blastomycosis present in horses?

•cutaneous lesions and or pneumonia: pyogranulomatous to granulomatous lesions

How does blastomycosis look on Microscopic Examination?

•Budding cell attached by a broad base to parent cell

T/F •Use caution when handling bodily fluids & practice good hygiene & disposal of waste

True

What are the different places that you can culture for blastomycosis?

ulcers, urine, vitreous, prostatic fluid, TTW, lymph node aspirate or biopsy

Infectious conidial phase grown at what temperature?

29 degrees Celsius

Some tests cross react with other dimorphic fungal pathogens or have ___ sensitivity

low

What are the FOUR different serology options for Blastomycosis?

Agar-gel immunodiffusion

EIA-enzyme immunoassay

Complement fixation and skin test are not reliable

Urine antigen test

What is the best choice for diagnosis of blastomycosis?

Urine PCR

Min. treatment for blastomycosis require __ or ___ ____ beyond resolution of clinical signs

1 months or 2 mo.

What are the THREE options for treating blastomycosis with drugs?

Itraconazole

Amphotericin B

Fluconazole

Relapse is related to what?

severity

T/F Crypto 8X more common in dog than cat.

fasle, more common in cats

What are THREE common spps of Cryptococcosis?

Cryptococcus neoformans

Cryptococcus gatti

Cryptococcus spp.

What animals feces is cryptococcosis typically growing well in and why?

Pigeon feces are rich in nitrogen-containing compounds including creatinine that favor the yeast's growth

Pathogenesis dependent on what THREE things?

Inoculum, strain virulence, and status of host’s defenses.

How do animals get infected with Cryptococcosis?

Infection by inhalation of spores from filamentous form or unencapsulated yeast

How would you find Cryptococcosis in the environment?

Unencapsulated in environment

What does the capsule of Cryptococcosis play into virulence?

Protects against phagocytosis

T/F the capsule interferes w/ leukocyte migration, depletes complement & inhibits T cell responses

True

In small animals what is the primary site of infection though pulmonary lesions can occur?

nasal cavity

What is a major clinical feature of cryptococcosis?

Bone lysis of maxillary region of oral cavity

What is the most common systemic fungal infection in cats?

Cryptococcosis

How does Cryptococcosis present clincally in cats? (4)

Respiratory disease with discharge

Production of masses and facial deformities

Cutaneous lesions common

Disseminates primarily to CNS

With cryptococcosis, Multifocal cutaneous lesions reflects ____

dissemination

How does cryptococcosis present in canine? (3)

Severe disseminated disease

Multiple organ involvement

CNS signs multifocal

What are the clinical features of Cryptococcosis?

Weight loss, inappetence, lethargy are common nonspecific findings.

Skin lesions, fever, & swollen lymph nodes.

What is a marker of dissemination for Cryptococcosis in dogs?

Cutaneous lesions

What is typically seen in cattle infected with cryptococcosis?

mastitis w/ regional lymph node involvement

How are the cattle infected with cryptococcosis?

Barns contaminated w/ pigeon feces

What are the TWO outcomes of Cryptococcosis?

•Reduced milk production due to excess granulation tissue

•Culling-no labeled treatment for cattle

How does Cryptococcosis present in horses?

Equine rhinitis or nasal granuloma

What do you have to differentiate from cryptococcosis in horses?

Conidiobolus

How does cryptococcosis physically look in horses?

•Gelatinous mass with minimal inflammation to granuloma formation

How does Cryptococcosis look microscopically?

Encapsulated, spherical yeast Single buds, narrow-based budding

What are the different things that you can do cytology on?

nasal discharge, skin exudates, CSF, tissue aspirates, or ocular paracentesis.

What can you culture for cryptococcosis?

LN aspirate, TTW, milk CSF, nasal

Latex agglutination for capsular AG in what TWO substances?

serum or CSF

T/F Ag titer positive at 1:16 or greater

True

What do you use to treat Cryptococcosis in cats?

Fluconazole

What do you use to treat Cryptococcosis in dogs?

Fluconazole, and amphotericin B should be added for dogs with disseminated disease

What do you use to treat Cryptococcosis in horses?

Debulking of nasal mass and topical azole treatment

Systemic azole treatment may be indicated following surgery

Treatment should continue until at least ____ cryptococcal antigen tests are negative

two

What is the therapy for cats?

•Should consider 6-18 months of therapy and continue 1 month after resolution

•May take 2+ years

•Relapses as late as 10 years