Medical Virology Examination Collection — OmpathStudy

MEDICAL VIROLOGY --- PAPER 1 — Mount Kenya University, University Examinations 2021/2022 School of Medicine, Dept. of Medical Microbiology MBChB Degree Unit Code: MBMM 3300 Unit Title: Medical Virology and Mycology (Paper 1) Date: Wed 26th Jan 2022, 2:00PM Main Exam Time: 3 Hours Section A — MCQs (Virology portion) Q19. Which of the following statements is true about the pathogenesis of HSV? a. Up to 90% of persons seropositive for HSV-2 antibody have a clinical history of anogenital herpes outbreaks b. Most persons who are seropositive for HSV-2 but report no symptoms still shed virus from the genital area intermittently c. HSV-2 is not associated with HIV acquisition or transmission d. All herpes viruses establish active infection in specific target cells e. All the above Answer: b Explanation: Many HSV-2 seropositive people are asymptomatic but still shed virus intermittently, which drives transmission. --- Q20. Which clinical presentation is typical of a primary first episode HSV-2 infection? a. No lesions or symptoms, HSV-1 antibodies may or may not be present, HSV-2 antibodies are present b. Lesions present, symptoms usually mild, HSV-1 antibodies may or may not be present, HSV-2 antibodies are present c. Lesions present, symptoms usually severe, HSV-1 and HSV-2 antibodies are not present d. Lesions present, symptoms usually moderate, HSV-1 antibodies are present, and HSV-2 antibodies are not present e. All the above Answer: c Explanation: A true primary infection occurs with no pre-existing antibodies (to either type) and presents with severe symptoms. --- Q21. Viruses that contain two complete copies of positive strand RNA and the enzyme reverse transcriptase are: a. Toga viruses b. Rhabdoviruses c. Retroviruses d. Reoviruses e. Enteroviruses Answer: c Explanation: Retroviruses are diploid (+)ssRNA viruses carrying reverse transcriptase to make a DNA copy for integration. --- Q22. Bacteriophages that can enter into stable, long-term relationships with their hosts are called: a. Lytic phages b. Defective phages c. Virulent phages d. Lazy phages e. Temperate phages Answer: e Explanation: Temperate phages integrate into the host genome (lysogeny), coexisting without killing the host. --- Q23. The positive strand of certain viruses does not act as a message but becomes converted into DNA and integrated into the host cellular DN A. These viruses are: a. Rhinoviruses b. Enteroviruses c. Retroviruses d. Reoviruses e. Picornaviruses Answer: c Explanation: Retroviral RNA is reverse-transcribed into DNA before integration; it is not used directly as mRN A. --- Q24. Infants infected with cytomegaloviruses (CMV) in utero may suffer from: a. Mental retardation b. Enlarged spleen c. Liver damage d. Any of these e. None of these Answer: d Explanation: Congenital CMV can cause a broad range of manifestations including all of the above. --- Q25. Viroids are unusual in that they: a. Have no capsid protein or envelope b. Contain RNA c. Are barely visible with the light microscope d. Can cause disease in plants e. Are retroviral Answer: a Explanation: Viroids are naked, small circular RNA molecules with no protein coat — this is their defining unusual feature. --- Q26. Creutzfeldt-Jakob disease (CJD), Kuru, scrapie, and Mad Cow disease are caused by: a. Viroids b. Retroviruses c. DNA viruses d. Prions e. RNA viruses Answer: d Explanation: These are transmissible spongiform encephalopathies caused by misfolded prion proteins. --- Q27. The human virus that has been associated with Burkitt's lymphoma (a malignant tumor of the jaw) is: a. Cytomegalovirus b. Human papilloma virus (HPV) c. Retroviruses d. Epstein-Barr virus e. Enterovirus Answer: d Explanation: EBV is strongly oncogenic and linked to Burkitt's lymphoma, especially in endemic (African) form. --- Q28. What causes Encephalitis or Acute Encephalitis Syndrome (AES)? a. Inflammation caused by an infection in the brain b. The main causative agents of this disease are viruses c. Both A and B d. Only B e. None of the above Answer: c --- Q29. What are the symptoms of Encephalitis or Acute Encephalitis Syndrome? a. High fever b. Vomiting c. Confusion d. A and B e. All the above Answer: e --- Q30. Treatments given to encephalitis or AES patients are: a. Corticosteroids b. Mechanical ventilation c. Anticonvulsants d. All the above e. A and C Answer: d --- Q31. Genital herpes are caused by the herpes simplex viruses: a. HPV, HSV-1 and HSV-2 b. HSV-1 and HSV-2 c. HTLV1 d. HIV, HSV-1 and HSV-2 e. All of the above Answer: b --- Q32. Which of the following statements is true about the transmission of HSV? a. The average incubation period is 10 days b. Likelihood of transmission does not change with increased duration of infection c. Does not change with increased duration of infection d. HSV is readily inactivated by drying and soap and water e. Most sexual transmission occurs while the source contact case is symptomatic Answer: d Explanation: HSV is an enveloped virus, so it