Answers to Mulitple Choice Questions - Paper 1
Instructions for candidates
The examination consists of 30 multiple choice
questions, each divided into 5 different parts. Each part
contains a statement which could be true or false. Each question
will have at least one part which is true. For each part, you
should indicate whether you think it is true (T), false (F), or
don’t know (DN). You must fill in the relevant square with a
black pen. One mark will be given for each correct answer and one
mark deducted for each incorrect answer. You will not be marked
for those questions for which you have indicated "don’t
know".
| 1. Viruses | |
| False | Contain both DNA and RNA |
| True | May have an envelope |
| False | Have their own metabolism |
| True | May contain enzymes for replication |
| False | Cell wall |
| Comments | Viruses contain either DNA or RNA but not both. Some may have an envelope. Unlike bacteria, they do not have a cell wall or their own metabolism. They may contain enzymes for replication. |
| 2. The following are DNA viruses | |
| True | Herpesviruses |
| False | Orthomyxoviruses |
| False | Enteroviruses |
| True | Hepadnaviruses |
| True | Parvoviruses |
| Comments | Herpesvirus and Hepadnaviruses are double stranded DNA viruses. Parvovirus is a single stranded DNA virus. Orthomyxoviruses and enteroviruses are singles stranded RNA viruses. |
| 3. The following are RNA viruses | |
| True | Picornaviruses |
| False | Adenoviruses |
| False | Papillomaviruses |
| True | Rhabdoviruses |
| True | Rotaviruses |
| Comments | Adenoviruses and papillomaviruses are double standed DNA viruses. Picornaviruses and rhabdoviruses are single stranded RNA viruses. Rotaviruses are double stranded RNA viruses. |
| 4. Live attenuated vaccines are available against the following viruses | |
| False | Influenza A Virus |
| False | Hepatitis B Virus |
| True | Rubella Virus |
| True | Yellow Fever Virus |
| True | Varicella-Zoster Virus |
| Comments | Live attenuated vaccines are available against rubella, yellow fever, and varicella-zoster viruses. Influenza A viral vaccines are either inactivated split or subunit vaccines. The vaccines in current use against hepatitis B are recombinant subunit vaccines. |
| 5. The following antiviral agents is active against the following virus | |
| True | Lamivudine and HIV |
| True | Lamivudine and HBV |
| False | Amantidine and influenza B virus |
| True | Ribavirin and RSV |
| True | Acyclovir and HSV |
| Comments | Lamivudine is a reverse transcriptase inhibitor active against both HIV and HBV. Amantidine is active against influenza A only. Ribavirin is active against RSV and acyclovir against HSV |
| 6. Herpes Simplex Encephalitis | |
| True | Commonly affect the temporal lobe |
| False | Is usually diagnosed by culture of the CSF |
| True | May be diagnosed by PCR of the CSF |
| False | Should be treated with IV ganciclovir |
| True | May be diagnosed by the finding of specific antibody in the CSF |
| Comments | Herpes Simplex Encephalitis commonly affect the temporal lobe. Culture of the CSF is usually unsuccessful. PCR of the CSF is a much better choice. A diagnosis can also be made by the detection of HSV-specific antibodies in the CSF. Herpes Simplex Encephalitis should be treated with IV acyclovir. |
| False | Causes a maculopapular rash |
| False | Respond to AZT therapy |
| True | Remains latent in sensory ganglia following primary infection |
| False | Recurrent episodes of Shingles usually occur |
| False | Patients with shingles are not infectious |
| Comments | VZV causes a vesicular rash. It does not respond to AZT as it does not possess reverse transcriptase. It remains latent in sensory ganglia following primary infection. It is rare for more than one episode of shingles to occur. Patients with shingles are infectious. |
| 8. Cytomegalovirus (CMV) | |
| True | Primary infection is usually symptomatic |
| True | An infectious mononucleosis-like syndrome may occur during primary infection. |
| True | May cause severe infection in immunocompromised individuals |
| False | Is teratogenic |
| False | Causes Kawasaki's Disease |
| Comments | Primary CMV infection is usually asymptomatic. Occasionally, an infectious mononucleosis-like syndrome may occur during primary infection. CMV is well known to cause severe disease in immunocompromised individuals, notably transplant recipients and patients with AIDS. Although it may cause severe congenital infection, it is not teratogenic. It attacks already formed fetal organs. It is not associated with Kawaski's disease. |
| 9. Epstein-Barr Virus (EBV) is associated with | |
| True | Infectious Mononucleosis |
| True | Hepatitis |
| True | Burkitt's lymphoma |
| True | Nasopharyngeal carcinoma |
| True | Oral leukoplakia |
| Comments | All the above |
| False | Fifth disease (erythema infectiosum) |
| True | Roseala Infantum |
| False | Kaposi's Sarcoma |
| True | Infectious Mononucleosis-like illness |
| False | Oral leukoplakia |
| Comments | Parvovirus is associated with Fifth disease (erythema infectiosum). HHV-6 is associated with Sixth disease (Roseala Infantum) HHV-8 is associated with Kaposi's sarcoma. Rarely, in adults, primary HHV-6 infection may result in an infectious mononucleosis-like illness. EBV is associated with oral leukoplakia |
| False | Are associated with genital cancers |
| True | May cause gastroenteritis |
| True | May cause conjunctivitis |
| True | May cause pneumonia |
| False | May cause warts |
| Comments | Human papillomaviruses are associated with genital cancers. Adenoviruses type 40 and 41 are associated with gastroenteritis. Adenoviruses may also cause conjunctivitis and pneumonia. Human papillomaviruses are associated with warts. |
| 12. Human Papillomaviruses | |
| False | HPV-6 and HPV-11 are associated with genital cancers |
| True | HPV-16 and HPV-18 are associated with genital cancers |
| True | Warts caused by papillomaviruses may respond to interferon therapy |
| False | Papillomavirus infection is commonly diagnosed by viral culture |
| False | Are associated with progressive multifocal leucoencephalopathy (PML) |
| Comments | HPV-16 and HPV-18 are associated with genital cancers. Warts caused by papillomaviruses may respond to interferon therapy although it is rarely used. Huamn Papillomaviruses cannot be grown in cell culture. Polyomavirus JC is associated with PML. |
| 13. Coxsackie B Virus is associated with the following | |
| True | Paralytic illness |
| True | Myocarditis |
| True | Bornholm's disease |
| True | Severe congenital infection |
| True | Meningitis |
| Comments | All the above |
| 14. Influenza A Virus | |
| True | May undergo antigenic shift and antigenic drift |
| True | May cause pandemics |
| True | Respond to rimantidine |
| True | Respond to neuraminidase inhibitors |
| False | Vaccination confers lifelong protection |
| Comments | Influenza A Virus may undergo antigenic shift and antigenic drift. Antigenic shifts result in pandemics. Influenza A virus will respond to rimantidine, which is a similar compound to amantidine. It will also respond to newly available neuraminidase inhibitors. Because of constant antigenic changes, vaccination will not confer lifelong immunity; it will last for one year only. |
| 15. Paramyxoviruses may cause | |
| True | Croup |
| False | Maculopapular rash |
| True | Pneumonia |
| True | Bronchiolitis |
| False | Diarrhoea |
| Comments | Paramyxoviruses most commonly cause croup. They may occasionally cause bronchiolitis and pneumonia. |
| 16. Respiratory Syncytial Virus (RSV) | |
| False | Respond to Amantidine |
| True | May cause bronchiolitis |
| True | May cause croup |
| True | May cause pneumonia |
| False | May be prevented by vaccination |
| Comments | RSV will not respond to amantidine. It most commonly cause bronchiolitis and pneumonia. Occasionally, it may cause croup. There is no vaccine available. |
| 17. Parvoviruses | |
| False | Causes Roseola Infantum |
| True | Causes Erythema Infectiousum |
| False | Is teratogenic |
| True | May cause abortion |
| True | May cause aplastic crisis in persons with haemolytic anaemias |
| Comments | Parvovirus causes erythema infectiousum. Although it may cause abortion and stillbirths, it is not teratogenic. It causes aplastic crisis in persons with haemolytic anaemias |
| False | Causes a vesicular rash |
| True | May cause encephalitis |
| False | May respond to acyclovir |
| True | May be prevented by HNIG |
| True | May be prevented by vaccination |
| Comments | Measles causes a maculopapular rash. It may cause encephalitis. It does not respond to acyclovir. Susceptible individuals may be protected by HNIG. A live attenuated vaccine is now given as part of universal vaccination in many countries. |
| 19. Rubella Virus | |
| True | The rash of rubella is similar to that caused by parvo and enteroviruses |
| True | Is teratogenic |
| True | Congenital rubella is charaterised by eye, ear and heart defects |
| True | Congenital rubella is diagnosed by the finding of rubella-specific antibody in the cord blood of infants |
| True | Infants with congenital rubella poses a great infectious risk. |
| Comments | The rash of rubella is similar to that caused by parvo and enteroviruses. It is teratogenic, the classical triad of congenital rubella consists of eye, ear and heart defects. Congenital rubella can be diagnosed by the finding of rubella-specific antibody in the cord blood of infants.Infants with congenital rubella poses a great infectious risk since they may excrete the virus for up to 1 year. |
| 20. Human T-lymphotropic virus 1 (HTLV-1) is associated with | |
| False | Burkitt's lymphoma |
| True | Adult T-cell lymphoma |
| True | Tropical Spastic Paraparesis |
| False | Multiple Sclerosis |
| False | Hodgkin's lymphoma |
| Comments | Human T-lymphotropic virus 1 (HTLV-1) is associated with Adult T-cell lymphoma and Tropical Spastic Paraparesis |
| 21. HIV Infection may lead to | |
| True | Dementia |
| True | Chronic Diarrhoea |
| True | CMV retinitis |
| True | Oesophageal candidiasis |
| True | Non-Hodgkin's lymphoma |
| Comments | All the above |
| False | HIV envelope antibody level |
| True | HIV-p24 antigen |
| True | CD4 count |
| False | HIV pro-viral DNA in leucocytes |
| True | HIV plasma RNA |
| Comments | HIV envelope antibody remains high at a constant level throughout the period of infection and is thus of no use as a prognostic marker. HIV-p24 antigen had been widely used as a prognostic marker in the past but has now been supplanted by HIV plasma RNA (viral load). The CD4 count provides important information on the stage of the disease. |
| 23. A chronic carrier state may occur in the following: | |
| False | Hantavirus Infection |
| False | Hepatitis A |
| True | Hepatitis B |
| True | Hepatitis C |
| False | Smallpox Infection |
| Comments | A chronic carrier state may occur with HBV and HCV infection. |
| True | HbeAg |
| True | Anti-HBc IgG |
| False | Anti-HBc IgM |
| True | HBV-DNA |
| True | HbsAg |
| Comments | In patients with chronic active hepatitis, HBV replication is present and hence HBV-DNA and HbeAg. HbsAg is present. Anti-HbcIgM is normally absent although it may occasionally be detected during periods of exacerbations. Anti-HBc IgG is present. |
| 25. The following statements are true | |
| True | Chronic HBV infection may respond to interferon therapy |
| True | Chronic HCV infection may respond to interferon therapy |
| True | Chronic HCV infection may respond to ribavirin therapy |
| True | Hepatitis Delta infection may be prevented by vaccination against HBV |
| False | Hepatitis E Infection may be prevented by vaccination |
| Comments | Chronic HBV and HCV infection may respond to interferon therapy. Chronic HCV infection may respond to ribavirin therapy; however ribavirin is usually given with interferon. Hepatitis Delta infection may be prevented by vaccination against HBV. There is no vaccine available against HEV. |
| 26. The following viruses can be transmitted by blood | |
| True | Hepatitis A |
| True | HIV |
| True | HTLV-1 |
| True | HBV |
| True | HCV |
| Comments | All the above viruses may be transmitted by blood |
| 27. Regarding viral infection of the central nervous system (CNS) | |
| True | Meningitis may occur together with encephalitis |
| True | Enteroviruses are one of the commonest causes of CNS infections in childhood |
| False | HSV encephalitis is a postinfectious encephalomyelitis |
| True | Measles encephalitis is a postinfectious encephalomyelitis |
| True | The detection of antibody in the CSF is a useful diagnostic marker |
| Comments | Meningitis usually occurs with encephalitis. Enteroviruses are one of the commonest causes of CNS infections in childhood. HSV encephalitis result from invasion of the virus rather than an allergic postinfectious event as in the case of measles. The detection of antibody in the CSF is a useful diagnostic marker |
| 28. The following viruses are associated with gastroenteritis | |
| True | Astroviruses |
| True | Norwalk-like viruses |
| False | Picornviruses |
| True | Adenoviruses |
| True | Rotaviruses |
| Comments | Although enteroviruses may be found in faeces, they are not associated with gastroenteritis |
| 29. The following viruses are transmitted from animals to humans | |
| True | Rabies Virus |
| False | Polioviruses |
| False | CMV |
| True | Hantaviruses |
| True | Lassa Fever Virus |
| Comments | Rabies may be transmitted to humans from a variety of mammals. Hantaviruses and Lassa Fever Virus may be transmitted to humans by rodents. |
| 30. The following is true of rabies virus | |
| False | The majority of cases world-wide result from bat bites |
| True | Infection may be prevented by active and passive immunisation |
| False | Human Rabies vaccine is a live attenuated vaccine |
| True | The animal reservoir differ from country to country |
| True | May be diagnosed by serology |
| Comments | The majority of human rabies cases world-wide result from dog bites. Infection may be prevented by active and passive immunisation. Although live attenuated vaccines are available for vaccinating animals, inactivated vaccines are used in humans for safety reasons. May be diagnosed by serology. |
