Lecture 27: Fungal diseases

How do you diagnose fungal infections?

• CBC/Chem, radiographs-inflammation

• Sample

• antigen assay

How do you treat fungal infections?

• Itraconazole (preferred)

• Ketoconazole (coccidomycosis)

• Fluconazole and Voriconazole (CNS)

• Amphotericin B (severe disease)

Etiology of coccidiomycosis?

• Found in sandy alkaline soil, hot and dry

• Arthospores are inhaled or enter woun, can come up to surface after rainfall and then spread by wind

• Digging behavior

CS of coccidiomycosis?

• Musculoskeletal

• Respiratory

• Skin nodules

• General illness

How is coccidioidomycosis daignosed?

Antigen assay, demonstrate organism by cytology, biopsy, culture, DNA, amplication

How do you treat coccidiodomycosis?

Ketoconazole (first choice)

Where is coccidiomycosis found?

Southwest

Risk factors of cryptococcus

Near logging area, hunting/outdoor activity, botanical gardens

CS with cryptococcus

• Subclincial carriers

• Nasal, pulmonary, CNS, SQ nodules

• Can be primary infection or secondary in immunocompromised patients

How is cryptococcus diagnose?

• Latex agglutination test

• Culture or PCR in cats w/ CS

• Cytology, histopathology or lesions (skin, lungs, LN)

How do you treat cryptococcus?

Itraconazole or fluconazole

Etiology of blastomycosis?

Humidity, fog, excavation sites, sandy and acidic soil near water. Inhalation of open wounds w/spores from environment or through lungs.

CS of blastomycosis?

Anorexia, cough dyspnea, lethargy, fever skin lesions, lameness, lymphadenopathy, masses in lung and spleen, uveitis

Treatment of blastomycosis

Itraconazole (itraconazole), if CNS, ocular symptoms, symptoms consider fluconazole and itraconazole

Where is histoplasmosis?

Mississippi, Missouri, Ohio River Valley, Mid-Atlantic

CS of histoplasmosis

General pulmonary, GI, liver, skin LN, joints

Diagnosis of histoplasmosis?

Same as coccidiomycosis and blastomycosis

Treatment histoplasmosis

Itraconazole

Etiology of aspergillus

Present in the environment and inhabits the nasal mucosa normally

CS of aspergillus

• Nasal discharge, sneezing, epistaxis, depigmentation of nasal planum, erosion and ulceration

• Disseminated, multiple organs and bones, respiratory entry and then hematogenous spread

• Nasal and ocular granulomas, neuro signs in cats

Diagnosis of aspergillus

• Histopathology, CT scans, fungal plagues on rhinoscopy

• Culture, cytology, histopathology

How do you treat aspergillus?

• Intranasal clotrimazole ± systemic therapy

• Similar to dogs but no anti-fungal topical creams intranasally

What is the primary causative agent of blastomycosis as discussed in the sources? a) Paracoccidioides brasiliensis b) Histoplasma capsulatum c) Blastomyces dermatitidis d) Coccidioides immitis

c) Blastomyces dermatitidis

In nature, Blastomyces dermatitidis grows in what form? a) Yeast b) Spherule c) Saprophytic mycelial form d) Arthroconidia

c) Saprophytic mycelial form

Which of the following animals is most commonly infected with Blastomyces according to the sources? a) Cats b) Horses c) Dogs d) Ferrets

c) Dogs

Proximity to which of the following is considered a risk factor for blastomycosis infection in dogs? a) Decaying plant matter b) Sandy, alkaline soil c) Waterways d) High altitudes

c) Waterways

How is blastomycosis primarily acquired? a) Direct contact with infected animals b) Inoculation into a wound c) Inhalation of spores d) Ingestion of contaminated soil

c) Inhalation of spores

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Which of the following is a common clinical sign in dogs with blastomycosis? a) Increased appetite b) Cough c) Bradycardia d) Decreased body temperature

b) Cough

Coccidioides immitis and Coccidioides posadasii exist in the environment as: a) Yeast b) Spherules c) Mycelium d) Macroconidia

c) Mycelium

What are the infective units of Coccidioides spp. that are inhaled from the environment? a) Endospores b) Yeast cells c) Spherules d) Arthroconidia

d) Arthroconidia

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In the United States, coccidioidomycosis is primarily found in which region? a) Southeastern states b) Northeastern states c) Southwestern United States d) Northwestern states

c) Southwestern United States

What is a characteristic structure formed by Coccidioides spp. in host tissues? a) Mycelium b) Arthroconidia c) Spherule d) Yeast

c) Spherule

What is the most common systemic mycosis in cats according to the sources? a) Blastomycosis b) Coccidioidomycosis c) Cryptococcosis d) Histoplasmosis

c) Cryptococcosis

Which two Cryptococcus species most commonly cause disease in animals? a) C. laurentii and C. albidus b) C. magnus and C. laurentii c) C. neoformans and C. gattii d) C. albidus and C. magnus

c) C. neoformans and C. gattii

Cryptococcus neoformans is commonly found in association with: a) Decaying wood b) Bird (especially pigeon) guano c) Sandy, acid soil d) Hollows of eucalyptus trees

b) Bird (especially pigeon) guano

What is a key virulence factor of Cryptococcus spp. that provides protection from phagocytosis? a) Melanin b) Mannitol c) Laccase d) Polysaccharide capsule

d) Polysaccharide capsule

What is the primary mode of transmission for cryptococcosis? a) Direct contact with infected animals b) Cutaneous inoculation c) Inhalation of airborne organisms d) Fecal-oral route

c) Inhalation of airborne organisms

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Histoplasma capsulatum is particularly prevalent in which geographical area of the United States? a) Pacific Northwest b) Ohio, Missouri, Tennessee, and Mississippi river valleys c) Southwestern desert regions d) Rocky Mountain states

b) Ohio, Missouri, Tennessee, and Mississippi river valleys

What is thought to be the form of Histoplasma capsulatum that is inhaled by mammalian hosts? a) Macroconidia b) Yeast cells c) Spherules d) Microconidia

d) Microconidia

Which animal is considered a primary reservoir for Histoplasma capsulatum and helps in its geographical dissemination? a) Dogs b) Cats c) Chickens d) Bats

d) Bats

In dogs with histoplasmosis, which body system is particularly susceptible to severe infiltration? a) Respiratory system b) Central nervous system c) Gastrointestinal tract d) Cardiovascular system

c) Gastrointestinal tract

What is a common clinical sign in dogs with histoplasmosis? a) Increased appetite b) Diarrhea c) Bradycardia d) Increased body weight

b) Diarrhea