Medical Virology CAT 2024/2025 — MKU MBMM OmpathStudy

Mount Kenya University — School of Medicine — Department of Medical Microbiology MBChB · Unit: MBMM 3333 – Medical Virology · End of Term CAT · May–Aug 2024/2025 · Date: 24/6/2025 Section A: MCQs 1. Common complication of influenza affecting the brain in children? a) Kawasaki disease b) Reye syndrome c) Guillain-Barré syndrome d) Myocarditis e) Both a and b Answer: b — Reye syndrome Explanation: Linked to aspirin use during viral illness, especially influenza or varicella, in children. 2. Respiratory virus most likely to cause bronchiolitis in young children? a) Rhinovirus b) Respiratory Syncytial Virus (RSV) c) Influenza virus d) Adenovirus e) Both a and c Answer: b — Respiratory Syncytial Virus (RSV) Explanation: RSV is the leading cause of bronchiolitis in infants. 3. Virus causing both upper and lower respiratory tract infections? a) Influenza virus b) Mumps virus c) Measles virus d) Rubella virus e) None of the above Answer: a — Influenza virus Explanation: Causes rhinitis and pharyngitis (upper tract) as well as pneumonia (lower tract). 4. Primary mode of transmission for most respiratory viruses? a) Fecal-oral route b) Airborne droplets c) Skin contact d) Vector-borne e) Both c and d Answer: b — Airborne droplets 5. Acute bronchiolitis and viral pneumonia are manifestations of: a) Upper respiratory tract infection b) Lower respiratory tract infection c) Tuberculous invasion d) AIDS e) Both a and b Answer: b — Lower respiratory tract infection Explanation: Both processes occur below the larynx. 6. Potential complication of chronic Hepatitis B infection? a) Jaundice b) Liver failure c) Cirrhosis d) All of the above e) Haemorrhagic fever Answer: d — All of the above 7. Test used to detect HBV surface antigen in blood? a) ELISA for IgM anti-HBc b) PCR c) HBsAg test d) Anti-HBs test e) Both a and b Answer: c — HBsAg test 8. Acute Hepatitis B infection can be characterized by: a) Flu-like symptoms b) Jaundice c) Hepatomegaly d) All of the above e) Both a and b Answer: d — All of the above 9. NOT a common route of HBV transmission? a) Sexual contact b) Sharing needles c) Fecal-oral route d) Blood transfusion e) None of the above Answer: c — Fecal-oral route Explanation: HBV is blood and body-fluid borne, not enteric. 10. Most reliable detection test for HBV? a) ELISA for IgM anti-HBc b) PCR for HBV DNA c) HBsAg test d) Anti-HBs test e) One can use a and d Answer: b — PCR for HBV DNA Explanation: Most sensitive and specific; it detects the viral genome directly. 11. NOT a common symptom of both dengue and chikungunya? a) Fever b) Joint pain c) Headache d) Skin rash e) Diarrhoea Answer: e — Diarrhoea Explanation: Not a hallmark of either infection. 12. Primary vector for both dengue and chikungunya viruses? a) Culex pipiens b) Anopheles gambiae c) Aedes aegypti d) Mansonia uniformis e) Culex vishnui Answer: c — Aedes aegypti 13. Most sensitive test for detecting dengue or chikungunya viral RNA early in infection? a) NS1 antigen test b) IgM antibody test c) PCR test d) IgG antibody test e) Rapid diagnostic test Answer: c — PCR test Explanation: Detects viral RNA before antibodies appear. 14. A 25-year-old female has sudden high fever, severe joint pain and rash after recent tropical travel. Most likely diagnosis? a) Malaria b) Typhoid fever c) Dengue fever d) Chikungunya fever e) Both dengue and chikungunya Answer: e — Both dengue and chikungunya Explanation: The clinical picture overlaps; laboratory testing is needed to distinguish them. 15. Dengue haemorrhagic fever is characterized by: a) High fever and severe headache b) Joint pain and muscle aches c) Bleeding, low platelet count and plasma leakage d) Skin rash and itching e) Vomiting and diarrhoea Answer: c — Bleeding, low platelet count and plasma leakage 16. Usual duration of acute hepatitis? a) Less than 6 months b) Less than 3 months c) About 6 weeks d) More than a year e) Lifelong Answer: a — Less than 6 months 17. Most common way to contract Hepatitis D? a) Fecal-oral route b) Sexual contact c) Blood transfusion d) Contact with infected body fluids e) All of the above Answer: e — All of the above Explanation: HDV requires HBV co-infection and shares its transmission routes. 18. Which hepatitis type can be prevented by vaccination? a) Hepatitis C b) Hepatitis B c) Hepatitis D d) Hepatitis E e) Both a and c Answer: b — Hepatitis B Explanation: Vaccinating against HBV also protects against HDV, but Hepatitis B is the direct answer. 19. Hepatitis B can be transmitted through: a) Mother to fetus b) Sexual contact c) Parenteral transmission d) All of the above e) Both a and b Answer: d — All of the above 20. HBV panel shows positive HBcIgG and HBsAb with negative HBsAg. Interpretation? a) Chronically infected b) Never exposed c) Had acute HBV in the past, now resolved d) Had chronic HBV and responded to interferon e) None of the above Answer: c — Past acute HBV, now resolved Explanation: Anti-HBc plus anti-HBs with no surface antigen indicates past resolv