Virology 3

Question 1

All of the following viruses are disseminated throughout the body EXCEPT ONE:

Accepted Answer

Human papilloma virus — HPV causes localized infections only and does not disseminate systemically via viremia. HIV, HBV, rabies virus, and yellow fever virus all cause systemic dissemination.

Question 2

All of the following associations are true EXCEPT ONE:

Accepted Answer

Astrovirus causes gastroenteritis only in adults — Astrovirus primarily affects children, not adults. All other associations are correct.

Question 3

Each of the following diseases is associated with infection by picornaviruses EXCEPT ONE:

Accepted Answer

Mononucleosis — Mononucleosis is caused by EBV (herpesvirus), not picornaviruses. Coxsackieviruses cause myocarditis, HAV causes hepatitis, enteroviruses cause meningitis and herpangina.

Question 4

All the following viruses belong to the Picornaviridae EXCEPT ONE:

Accepted Answer

Rabies virus — Rabies virus belongs to the Rhabdoviridae family. Coxsackievirus, rhinoviruses, poliovirus, and echovirus are all members of the Picornaviridae family.

Question 5

Which one of the following statements concerning mumps is CORRECT?

Accepted Answer

The testes, ovaries and pancreas can be involved — Mumps complications can include orchitis, oophoritis, and pancreatitis, in addition to the classic parotitis. There is an effective vaccine, and diagnosis can be made through laboratory methods. There is only one serotype.

Question 6

Each of the following statements concerning HAV is correct EXCEPT ONE:

Accepted Answer

The diagnosis is usually made by isolating the virus in cell culture — Hepatitis A virus (HAV) is very difficult to culture. Diagnosis is typically made by detecting IgM anti-HAV antibodies using ELISA.

Question 7

Acute hemorrhagic conjunctivitis is caused by which of the following viruses:

Accepted Answer

Enterovirus — Enterovirus 70 and Coxsackievirus A24 are the primary causative agents of acute hemorrhagic conjunctivitis.

Question 8

Which of the following statements about CNS viral infections is FALSE?

Accepted Answer

HSV encephalitis is a post-infectious encephalomyelitis — HSV encephalitis is a direct viral invasion of the brain, not a post-infectious encephalomyelitis. Measles encephalitis, on the other hand, is a post-infectious encephalomyelitis.

Question 9

A 28-year-old female sex worker with HIV presents with headaches and CSF showing reduced glucose, elevated protein, 450 mononuclear cells/mL. Compatible with Cryptococcus, Coccidioides, or Candida meningitis. Which test is confirmatory for Candida?

Accepted Answer

Microscopic observation of oval yeast cells and pseudohyphae in CSF — For Candida meningitis, microscopic observation of oval yeast cells and pseudohyphae in the CSF is confirmatory. Cryptococcus is confirmed by antigen tests, and Coccidioides by serology (complement fixation).

Question 10

KOH examination of sputum from a heart transplant patient with fever and pulmonary infiltrates shows oval budding yeast cells and pseudohyphae. What is the diagnostic significance?

Accepted Answer

No diagnostic significance — The presence of Candida in sputum often represents colonization rather than invasive pulmonary candidiasis. Diagnosis of pulmonary candidiasis requires evidence from tissue biopsy, not just sputum examination.

Question 11

Which statement about phaeohyphomycosis is correct?

Accepted Answer

Phaeohyphomycosis may exhibit several clinical manifestations including subcutaneous or systemic disease, as well as sinusitis — Phaeohyphomycosis has a wide clinical spectrum. Infected tissue reveals darkly pigmented hyphae. While opportunistic, it can occur in immunocompetent individuals. Itraconazole is an effective treatment.

Question 12

All of the following are zoophilic dermatophytes — select all:

Accepted Answer

Microsporum canis — Microsporum canis (dogs/cats), Trichophyton equinum (horses), Trichophyton simii (monkeys), and Microsporum nanum (pigs) are all zoophilic dermatophytes.

Question 13

What is the most reliable laboratory method for the isolation of Trichophyton rubrum?

Accepted Answer

Skin scrapings microscopic examination using KOH — Microscopic examination of skin scrapings with KOH is the most reliable and practical first-line diagnostic test for dermatophytosis, including Trichophyton rubrum.

Question 14

Which of the following dermatophytes does NOT have the spore form characteristic called Microconidia?

Accepted Answer

Epidermophyton spp — Epidermophyton floccosum produces only macroconidia and lacks microconidia, which is a key distinguishing laboratory feature.

Question 15

Aflatoxins are a serious problem because:

Accepted Answer

They are potent carcinogens — Aflatoxins are potent hepatocarcinogens, which makes them a significant global public health concern.

Question 16

More visible symptoms of fungal infection are appearing recently because:

Accepted Answer

All of the above — The increase in visible fungal infections is multifactorial, including environmental changes, pathogen evolution, identification of new species, and a growing population with compromised immune systems.

Question 17

Aflatoxins are produced by which fungus?

Accepted Answer

Aspergillus parasiticus/flavus — Aflatoxins are produced by Aspergillus parasiticus and Aspergillus flavus.

Question 18

Which of the following is NOT a characteristic of histoplasmosis?

Accepted Answer

Person to person transmission — Histoplasmosis is not transmitted from person to person. It is acquired by inhaling spores from the mycelial phase found in soil, particularly associated with bird and bat droppings.

Question 19

Immunocompromised persons suffer from several fungal diseases. Which is LEAST frequently associated?

Accepted Answer

Malassezia furfur — Malassezia furfur typically causes superficial skin infections in immunocompetent individuals and is the least virulent among the listed fungi in immunocompromised hosts.

Question 20

Each of the following statements concerning Candida albicans is correct EXCEPT:

Accepted Answer

albicans is transmitted primarily by respiratory aerosol — Candida albicans is primarily transmitted through direct contact with mucous membranes or skin, or via endogenous flora. Respiratory aerosol transmission is not the primary mode.

Question 21

Each of the following statements concerning Cryptococcus neoformans is correct EXCEPT:

Accepted Answer

Pathogenesis is related primarily to the production of exotoxin A — The pathogenesis of Cryptococcus neoformans is related to its polysaccharide capsule, melanin, and urease, not exotoxin A. Exotoxin A is produced by Pseudomonas aeruginosa.

Question 22

Natural habitat for Paracoccidioides brasiliensis is:

Accepted Answer

Soil — The natural habitat for Paracoccidioides brasiliensis is soil.

Question 23

Coccidioidomycosis is also called:

Accepted Answer

Valley fever — Coccidioidomycosis is also known as Valley fever.

Question 24

One of the most common mycotoxins that infects nuts and grains and causes severe reactions is:

Accepted Answer

Aflatoxins — Aflatoxins are common mycotoxins that infect nuts and grains and can cause severe reactions.

Question 25

Coccidioides immitis can exist as molds in soil and spherules in tissues. This characteristic makes it:

Accepted Answer

Dimorphic — The ability of Coccidioides immitis to exist in two distinct forms (mold in soil and spherules in tissues) classifies it as dimorphic.

Question 26

Which of the following statements about the Herpesvirus Family and meninges is correct?

Accepted Answer

Mucous membranes — While HSV can infect neurons, leading to encephalitis, and can be latent in neurons, the question in the context of meninges might be referring to HSV involvement. However, the live site's correct answer indicates D (Meninges) as a target. The PDF version listed E as Mucous membranes being the correct answer when the options were different. Given the options provided and the original note, 'Mucous membranes' is likely the intended correct answer for a broader context or if the question aimed at initial infection sites rather than latency/dissemination in the context of meningeal involvement from initial infection.

Question 27

Which of the following factors is NOT typically considered a factor in resistance to viral infection?

Accepted Answer

Size of the viral genome — While the size of the viral genome can influence viral replication and pathogenesis, it is not a factor of the host's resistance. Level of immunocompetence, immunization history, age, and gender can all influence an individual's susceptibility and resistance to viral infections.

Virology 3

Questions, Answers & Explanations