Medical Virology & Mycology Paper Two OmpathStudy

Mount Kenya University — Medical School — Department of Medical Microbiology MBChB · Unit: MBMM 3300 – Medical Virology and Mycology · Main Exam 2022/2023 · Date: Wednesday 12th July 2023 Section A: MCQs 1. Fungus most likely found within reticuloendothelial cells? a) Histoplasma capsulatum b) Sporothrix schenckii c) Cryptococcus neoformans d) Candida albicans e) Rhizopus stolonifera Answer: a — Histoplasma capsulatum Explanation: An intracellular yeast that resides within macrophages and reticuloendothelial cells. 2. Aspergillosis is recognized in tissue by the presence of: a) Metachromatic granules b) Pseudohyphae c) Septate hyphae d) Budding cells e) Lesions Answer: c — Septate hyphae Explanation: Septate hyphae with acute-angle branching. 3. Fungi colonize lesions caused by other agents. Which is the least likely colonizer? a) Candida b) Sporothrix c) Mucor d) Aspergillus e) All of the above Answer: b — Sporothrix Explanation: It is a primary pathogen introduced by inoculation rather than a secondary coloniser. 4. A girl pricked her finger while pruning roses; a pustule became an ulcer with nodules along the lymphatics. Likely agent? a) Aspergillus fumigatus b) Sporothrix schenckii c) Cryptococcus neoformans d) Candida albicans e) Histoplasma capsulatum Answer: b — Sporothrix schenckii Explanation: The classic rose gardener's disease. 5. In immunocompromised persons, which fungal disease is least frequently associated? a) Cryptococcus neoformans b) Aspergillus fumigatus c) Malassezia furfur d) Mucor species e) None of the above Answer: c — Malassezia furfur Explanation: Usually a superficial skin commensal rather than a major invasive opportunist. 6. Which statement about Cryptococcus neoformans is INCORRECT? a) Natural habitat is soil, especially pigeon droppings b) Budding yeasts are found in lesions c) The initial site of infection is usually the lung d) Pathogenesis is primarily due to exotoxin A e) All of the above Answer: d — Pathogenesis is primarily due to exotoxin A Explanation: Cryptococcal virulence rests on its polysaccharide capsule; exotoxin A is a Pseudomonas toxin. 7. Fungal cells reproducing by budding are seen in infected tissues of patients with: a) Candidiasis, cryptococcosis and sporotrichosis b) Mycetoma, candidiasis and mucormycosis c) Tinea corporis, tinea unguium, tinea versicolor d) Sporotrichosis, mycetoma, aspergillosis e) Rhizopus, candidiasis, mucormycosis Answer: a — Candidiasis, cryptococcosis and sporotrichosis 8. NOT a characteristic of histoplasmosis? a) Person to person transmission b) Specific geographic distribution c) Yeasts in tissue d) Mycelial phase in the soil e) None of the above Answer: a — Person to person transmission Explanation: Acquired by inhaling spores from soil contaminated with bird or bat droppings, not spread between people. 9. Dermatophyte infection is most often associated with: a) Intravenous drug abuse b) Inhalation from contaminated bird faeces c) Adherence of the organism to perspiration-moist skin d) Fecal-oral transmission e) Droplet inhalation Answer: c — Adherence of the organism to perspiration-moist skin 10. Which statement about Candida albicans is INCORRECT? a) Budding yeast that forms pseudohyphae in tissue b) Causes thrush c) Transmitted primarily by respiratory aerosol d) Impaired cell-mediated immunity predisposes to disease e) None of the above Answer: c — Transmitted primarily by respiratory aerosol Explanation: Candida infection is usually endogenous or contact-acquired, not respiratory. 11. Moniliasis is a disease caused by: a) Histoplasma capsulatum b) Coccidioides immitis c) Candida albicans d) Cryptococcus neoformans e) Paracoccidioides brasiliensis Answer: c — Candida albicans Explanation: Moniliasis is an older name for candidiasis. 12. Cryptococcus neoformans causes: a) Meningitis b) Bone tuberculosis c) Typhoid d) Food poisoning e) Whooping cough Answer: a — Meningitis 13. Medium used to isolate fungi? a) Blood agar b) Sabouraud dextrose agar c) Chocolate agar d) Nutrient agar e) All of the above Answer: b — Sabouraud dextrose agar 14. Dermatophytes are fungi which: a) Require complex growth media b) Invariably invade subcutaneous tissue c) Cause systemic infections d) Live in superficial keratinized skin, hair and nail e) Are dimorphic Answer: d — Live in superficial keratinized skin, hair and nail 15. Candida albicans is noteworthy as the aetiological agent of: a) Thrush b) Valley fever c) Desert fever d) Rheumatic fever e) Yellow fever Answer: a — Thrush 16. NOT classified as a dermatophyte: a) Microsporum gypseum b) Trichophyton mentagrophytes c) Trichophyton rubrum d) Candida albicans e) Epidermophyton floccosum Answer: d — Candida albicans Explanation: It is a yeast, not a dermatophyte. 17. Ringworm is caused by: a) Candida albicans b) Cryptococcus neoformans c) Trichophyton rubrum d) Histoplasma capsulatum e) Round worms Answer: c — Trichophyton rubrum 18. The cell wall of the fungus: a) Is made of chitin b) Pro