الحترمونا من خري الدعاء

Transcription

1 الحترمونا من خري الدعاء 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 may contain DNA RNA Glycoprotein Enzymes Cell wall 2. Viruses are Obligate intracellular parasites May divide by binary fission Have their own metabolism May contain enzymes for replication May have an envelope 3. The following statements are true All viruses are sensitive to antiviral agents Virus infected cells may be transformed. Viruses may have a lipid envelope Viruses may produce cytopathic changes in cell culture Some viruses are destroyed by lipid solvents 4. The following are direct detection methods Detection of rotavirus antigen in faecal specimens Western blot

2 CMV DEAFF test Electron microscopy Polymerase chain reaction 5. The following methods may be used for serological diagnosis Complement-fixation tests Polymerase chain reaction Single Radial Haemolysis CMV DEAFF test Western blot 6. A serological diagnosis of a primary viral infection may be made Detection of viral-specific IgA Detection of viral-specific IgD Detection of viral-specific IgE Detection of viral-specific IgM Seroconversion 7. The following are examples of viral genome detection (molecular methods) Southern blot Western blot RIBA (Recombinant immunoblot assay) Branched DNA Polymerase chain reaction 8. The following statements are true For cytomegalovirus (CMV), the cytopathic (CPE) effect usually appears within hours For some viruses, the CPE is so characteristic that so further identification is required. Paramyxovirus causes syncytia formation in cell culture A given virus produce identical CPE in different cell cultures

3 Immmunofluroescence may be used to identify a virus in cell culture 9. Poliovirus can be typed by Single radial haemolysis Haemagglutination inhibition test DEAFF test Neutralization test Hybridization with specific nucleic acid probes 10. Immunofluorescence techniques can be used to detect the following directly from the specimen. Chlamydia CMV Respiratory Syncytial Virus (RSV) Influenza virus Rabies virus 11. The following statements are true for the haemagglutination-inhibition (HAI) test. Not a quantitative test Treatment of patient serum is necessary to remove non-specific inhibitors Animal blood is necessary Usually more specific than complement fixation tests (CFT) May be used for the diagnosis of rubella infection 12. Regarding cell culture Viruses can only be cultured using cell lines The presence of cytopathic effect is the only way to detect a virus The neutralization test is the mainstay of identification of a poliovirus isolate The haemagglutination inhibition test is the mainstay of identification of a respiratory syncytial virus (RSV) isolate Whole blood is the specimen of choice for many common viruses

4 13. A standard Polymerase Chain Reaction (PCR) consists of Denaturation, annealing, and ligation steps Denaturation, annealing, and extension steps dntps Mg++ ions Taq polymerase 14. Modification of a standard PCR include Nested PCR branched DNA (bdna) RT-PCR (Reverse transcription PCR) Quantitative PCR 3SR (Isothermal amplification) 15. Safety measures for preventing PCR contamination include The use of uracil-n-glycosylase (UNG) Use of filtered pipette tips Separate areas for master mix, template, and PCR product operation Dedicated pipettes for master mix, template, and PCR products Ultraviolet irradiation 16. The following statements are usually true PCR is more sensitive than branched DNA assays Branched DNA is more sensitive than Ligase chain reaction Exponential amplification occurs in PCR Linear amplificiation occurs in branched DNA PCR is extremely liable to contamination 17. Clinical diagnosis of infectious mononucleosis include Detection of VCA-IgM

5 Detection of VCA-IgA Seroconversion against EBNA Paul-Bunell test VCA IgG avidity test 18. Viruses that routinely establish latent infections in human sensory ganglia include Epstein-Barr virus Herpes Simplex Virus type 1 Varicella-Zoster Virus Herpes Simplex Virus type 2 Human herpesvirus Rapid diagnosis of CMV disease include CMV pp65 antigenaemia Conventional cell culture DEAFF test Detection of CMV-DNA in blood by PCR Rising antibody titres 20. The following viruses are associated with respiratory infections Rotaviruses Adenoviruses Influenza viruses HTLV-1 RSV 21. The following viruses are thought to cause gastroenteritis Enteroviruses Adenoviruses Norwalk-like viruses

6 Astroviruses Rotaviruses 22. The following viruses are transmitted from animals to humans Influenza A H5N1 HTLV-1 Hantaviruses Poliomyelitis Rabies 23. A chronic carrier state may occur in the following: Hepatitis A Hepatitis B Hepatitis C Hepatitis Delta Hepatitis E 24. The following viruses are transmitted by blood Rubella HIV Measles HBV HCV 25. The following may be useful for prognostic purposes in HIV-infected individuals HIV envelope antibody HIV-p24 antigen CD4 count CD8 count HIV viral load

7 26. The following markers are usually present in a hepatitis B carrier with chronic active hepatitis HbsAg HbsAb Anti-HBc IgM HBV-DNA HBeAg 27. Regarding viral infection of the central nervous system (CNS) Meningitis may occur together with encephalitis Enteroviruses are one of the commonest causes of CNS infections in childhood Electron microscopy of the cerebrospinal fluid (CSF) is a useful diagnostic test PCR has no role in the diagnosis of CNS infections The detection of antibody in the CSF is a useful diagnostic marker 28. Regarding rash illnesses Varicella-zoster virus (VZV) infection may cause a vesicular rash The rash caused by parvovirus B19 is due to the presence of virus in the skin Measles is usually diagnosed by viral culture Herpes simplex virus (HSV) infection is usually diagnosed by viral culture VZV cannot be grown in cell culture 29. Rubella infection can be asymptomatic may be indistinguishable from parvovirus B19 can have serious side effects when occurring in a woman in the third trimester of pregnancy is usually preventable by vaccination may be acquired by having close contact with an infant with congenital rubella syndrome 30. Regarding laboratory tests for rubella Rubella immunity may be determined by an enzyme immunoassay CFT is commonly used for the diagnosis of acute infection IgM antibody is usually detectable after the onset of rash Rubella virus cannot be cultured

8 Pre-natal diagnosis of rubella in a foetus is simple and reliable