LEC 5 - Systemic Mycoses Flashcards by Raegan Chambers

What do all biphasic/dimorphic soil fungi cause?

Pulmonary disease

which can spread to other areas

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What are the three/four examples of edemic fungi?

Coccidioides immitis + posadasii
Histoplasma capsulatum
Blastomyces dermatitidis

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Define: Edemic pathogen

Restricted to specific geographical region

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What are other names for coccidiodes?

Coccidioidomycosis
San Joaquin Valley Fever
Cocci

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Where is C. Posadasii located?

Argenitina

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Where is C. Immitis located?

California

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Morphology of Coccidioides

Biphasic
Non-Dimorphic = Spherule + Mold
NO YEAST FORM

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What does coccidioides look like in tissue?

Nonbudding spherules

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Describe: Spherules

Rich in lipids

Surrounds by giant cell

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What is another name for Spherules?

Endosporulating spherule

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What do spherules do?

Release endospores

These will then form new spherules

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What tissues are susceptible to spherules?

Lungs 
Skin 
Cardiac 
Pericardium 
Bones 
CNS

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How is coccidiodies found in nature?

Hyphae
Alternate between barrel-shapped arthrospores/empty
– and –
Disjunctor cells

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How long does it take Coccidioides to become mold in culture?

1 to 2 wks

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What type of agar is used for Coccidioides growth?

Sabouraud agar

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Define: Coccidioidin

Hyphal antigen

Used for immunodiagosis

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What animal is most affected by coccidioides?

Dogs

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What type of infection do pigs and cattle get?

Subclincal or inapparent

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What is the most common infection type with coccidioides?

Pulmonary

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What form of coccidioides is inhaled?

Arthroconidia

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What is the incubation period of coccidioides?

7 to 20 days

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What happens when coccidioides arthroconidia are inhaled?

Spherules with endospores form in lungs (and elsewhere)

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What is the primary CONDITION seen in humans with coccidioides ?

Pneumonia or influenza like symptoms
Most are benign or inapparent
Self-limitign most of the time

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Where does the agressive form of coccidioides tend to spread?

Lungs + Skin + Bones + Joints + CNS

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What ethnicities tend to be most affected by coccidioides ?

Asians Blacks Hispanics

What clinical signs are seen in dogs with a coccidioides infection?

``` Fever Lethargy Inappentence Lameness Coughing Dyspnea Bone swelling Wt. Loss ```

Define: erythema Nodosum

Tender red cutaneous nodules in shin region | Delayer hypersensitivity to fungal antigens

What is Erythema Nodosum a good indicator of? Why?

Good prognosis | Cell-mediated immunity is functional

Soil dwelling structures of coccidioides

Arthroconidia | Hyphae

What are ways to diagnose an animal with coccidioides?

Septum/Bronchoalveolar lavage - Sperules | PAS - Histopathilogical exam of affected tissue

Histological description of coccidioides

Giant cells w/ spherules

What blood work can be done to test for coccidioides?

IgG + IgM with Ab's to coccidiodin

BSL: coccidioides

BSL3

DOC: coccidioides

Triazoles (Fluconazole + Itraconazole) | Before lab confirmation

How long is therapy for coccidioides?

~ 1 year for dogs

Control: coccidioides

Reduce dust by water dirt + planting vegetation + paving road Infection allows for immunity

What is the telemorph of Histoplasma capsulatum called?

Ajellomyces capsulatus

What does H. Capsulatum produce disease in?

Dogs + Cats + Humans

How many variants of H. Capsulatum are there?

Morphology: H. Capsulatum

Dimorphic Uninucleated budding cells Mold = micro/macroconidia Tuberculate macroconidium

What cell types do H. Capsulatum like to reside in?

Macrophages + PMNs

What type of parasite is H. Capsulatum?

Facultative intracellular parasite

What does the mold of H. Capsulatum look like in culture?

Cottony mold

How long does it take H. Capsulatum to grow?

12 weeks

How is H. Capsulatum inhaled?

Microcondidia

What happens to the microcondidia once it is inhaled?

Becomes yeast cells

Clinical signs in humans: H. Capsulatum

Influenza like symptoms Non-productive cough + Fever Self-limiting

Why might dissemiated disease due to H. Capsulatum happen in dogs and cats?

Impaired cell-mediated immunity

What can the body do to H. Capsulatum yeast once in the lungs?

Phagocytosed by alveolar macrophages | = transported deeper into the body

HUMANS: What types of lesions occur with H. Capsulatum? Where?

Granulomatous foci in lungs + spleen

DOGS/CATS: What types of lesions occur with H. Capsulatum? Where?

Granulmatous lesions in lungs sometimes

What can a H. Capsulatum progress to that can lead to death in dogs?

Diesseminated histoplasmosis

How does disseminated histoplasmosis present in dogs?

Ulcerative intestinal lesions = diarrhea

How does disseminated histoplasmosis present in horses?

Lymphocutaneous lesions

What treatment is recommended in horses with disseminated histoplasmosis?

Amphotericin B

Virulence Factors: H. Capsulatum

Urease Ammonia Bicarbonate

What state of H. Capsulatum produces the virulence factors?

Yeast

What do the virulence factors produced by H. Capsulatum yeast cause?

Raise pH | Blunt/Eliminate killing action of phagolysosome

How does host resistance occur in regards to H. Capsulatum?

PMN expresses fungistatic activity + functional T cell-mediated immunity critical

What manifests 100% of the time in humans with disseminated disease from H. Capsulatum?

Fever

Where is H. Capsulatum most commonly found?

Eastern US

Transmission: H. Capsulatum

Aerosol of microconidia

What type of soil conditions does H. Capsulatum prefer?

Bat guano -- or -- Bird droppings

How can H. Capsulatum be ID'ed?

Direct microscopic exam Culture Histoplasmin

Culture: H. Capsulatum

Tuberculate macrocondia in culture

What do you get a culture for H. Capsulatum from?

Sputum Urine Lesions Buffy coat

Stain: H. Capsulatum

Giemsa-stained smears of marrow or blood

Therapy: H. Capsulatum

Itraconazole + Amphotericin B | most patients need no treatment

Sexual stage: Blastomyces Dermatitidis

Ajellomyces dermatitidis

Major clinical sign: B. Dermatitidis

Chronic granulomatous disease

Morphology: B. Dermatitidis

Thermally dipmorphic

Appearance in tissue/exudate: B. Dermatitidis

Multinucleate, broad-based budding cell

Appearance in culture: B. Dermatitidis

Hyphae bear conidia + chlamydospores

Infection phase: B. Dermatitidis

microcondidia or mycelial fragments from soil

Animals B. Dermatitidis produces disease in

Humans + Dogs

Clinical symptoms: B. Dermatitidis

Pulmonary disease

Where can B. Dermatitidis deseminate to?

skin + eyes + bone

Define: BAD1

B. Dermatitidis | Promotes adhesion to respiratory epithelium

Epidemiology: B. Dermatitidis

Ohio + Mississippi river Mexico Central america Some of Africa

What is a sign disseminated disease has occurred with B. Dermatitidis ?

Metastatic skin lesions

Culture: B. Dermatitidis

Sabouraud agar