1. Problem 1 (1) A 20-years old student with fever, malaise, headache, diffuculty in sleeping, & healed scar on his arm due to dog bite. Final diagnosis was rabies. Q. What is the aetiology?

2. A. Rabies virus. Q. How do you confirm diagnosis ?

3. A.@ Virus detection by immunoflurescence in corneal scraping & skin biopsy. @ Viral culture from saliva @ Antibody serology. @ detection of Negri bodies in brain biopsy after death. @ Animal inoculation. Q. What is the reservoir of rabies ?

4. A. Bats, birds, dogs, foxes, other warm- blooded animals. Q. How is rabies prevented ?

5. A.@ Rabies vaccine from tissue culture. @Passive immunization.

6. Problem 2 (1) A 30-years old woman c/o nausea, vomiting, swelling of fingers, malaise, fatigue,anorexia, upper abdominal pain, & dark urine. She was found to have hepatomegaly & tender liver.Lab. tests showed positive urine bilirubin, high serum bilirubin,& raised ALT test. Final diagnosis was viral hepatitis. Q. Which viruses are to blame ?

7. A. Hepatitis A, B, C, D viruses – EB virus – CMV– yellow fever virus Q. Which tests you perform to establish the aetiology ?

8. A. *HAIgM antibody *HBcIgM *HBsAg *HBsAb *HCV IgG antibody *Serology for other viruses.

9. (2)Results of serology are : *HAIgM-negative *HBsAg-positive, *HBcIgM-poasitive, *HBsAb-negative *HCV IgG – negative *Other tests negative. Q.What is the diagnosis ?

10. A. Acute hepatitis B Q.What is the diagnosis if: *HAIgM –negative *HBsAg-negative *HBcIgM-positive *HBsAb-negative *Other tests negative ?

11. A. Acute hepatitis B (Recent infection ). Q. What is the diagnosis if: *HAIgM-negative *HBsAg-negative *HBcIgM-negative *HbsAb-positve *Other tests negative ?

12. A. Past infecion & immunity to hepatitis B Q. How did the patient acquire infection?

13. A. May be blood transfusion, sexually, intravenous narcotics,

14. (3) Patient improved, & tests one year later showed posotive HBsAg & HbsAb was negative. Q. Explain Why ?

15. A. Chronic carrier of HBV Q. What test you do to show if she is infectious to others ?

16. A. HBeAg

17. Problem 3 (1) An 18-year old woman c/o painful sore throat, malaise, anorexia, fever, & headache. She had DPT vaccine in childhood. O/E : tonsils swollen & full of exudates, no membrane in pharynx, liver tender & enlarged Q. Which lab. test you do to reach a diagnosis ?

18. A. Throat culture for S.pyogenes + Monospot test. (2) Throat culture revealed alpha hemolytic streptococci, Monospot test –negative, ALT & AST were raised, WBC 16000. Q. So, what is your diagnosis ?

19. A. Early infectious mononucleosis (IM) with negative Monospot test. (supported by LFT)

20. (3) Several days later Monospot test was positive and lymphocytosis was detected (15% of lymphocytes were atypical ). So final diagnosis of infectious mononucleosis was made. Q.What is the causative agent ?

21. A. EBV Q.How is Infection transmitted?

22. A.Kissing (EBV is found in saliva) Q. In what age group is it more common?

23. A. Young adults. Q. What are heterophil antibodies?

24. A.They are nonspecific antibodies formed during EBV infection. Diagnosis is confirmed by EBV IgM antibody. Q. Do you need to isolate EBV in tissue culture?

25. A.No, culture not done routinely. Q. Can IM be contracted more than once?

26. A. No, only once – it gives life –long immunity. Q. Is there any way of prevention ?

27. A. No vaccine or drug to prevent infection.

28. Problem 4 A 45-year old man c/o behavioral changes & impaired consciousness. Final diagnosis was viral encephalitis Q. What viruses involved ?

29. A. H.simplex types 1&2, Mumps, Measles, Varicella- zoster, Polio, ECHO, Coxackie, Influenza, Rubella, Rabies, arthropod –borne viruses (St.Louis,Japanese B). Q. What are the human Herpes viruses ?

30. A. HSV-types 1 & 2, Varicella-zoster, EBV, CMV, Herpes virus types 6 & 7. Q. Describe the lab. diagnosis of viral encephalitis.

31. A. * Brain biopsy in which virus is detected by IF, electron microscopy, tissue culture. *Serology for herpes. * CSF for herpes antibodies. *Throat swab for viral culture. * Stool for Enterovirus culture

32. Problem 5 (1) A 32-year old woman with fever, headache,shivering, cough, muscle pain, & painful eyes. Final diagnosis was influenza. Q. What are the causative agents ?

33. A. @ Influenza viruses A & B @ RSV (elderly ) @ Adenovirus @ Parainfluenza viruses @ Mycoplasma pneumoniae @ Chlamydia spp. Q. Give influenza serious complication?

34. A. Pneumonia : Viral or bacterial Q. What specimens to collect ?

35. A. @ Throat swab or nasopharyngeal aspirate for viral culture @ Blood for serology @ Sputum for both bacterial & viral culture @ Blood culture for bacteraemic pneumonia Q. What are the virological tests you perform ?

36. A. @ Tissue culture @ Immunoflurescence for antigens of : *Influenza viruses A,B *RSV *Parainfluenza viruses *Adenoviruses *Chlamydia spp. Q. How are influenza viruses classified ?

37. A.@ Influenza A, divided into many subtypes according to neuraminidase (N) molecule & haemagglutinin (H) molecule @ Influenza B @ Influenza C (not serious ) Q. Is influenza preventable ?

38. A. Yes, by : @ An inactivated vaccine containing the 3 viruses 70% effective for one year only. Vaccine is recommended for people at risk e.g. those c/o asthma, heart diseases, renal failure, diabetes, old age, immunosuppression. @ Amantadine prophylaxis.

39. Problem 6 (1) A 27-year old man attended the lab. for HIV test. Q. How is HIV transmitted ?

40. A. @ Sexual @ Mother to baby @ Blood transfusion @ Sharing of needles among drug addicts @ Needle stick injuries Q. What is the basis of HIV test ?

41. A.To detect antibodies of HIV Q. When does this test become positive?

42. A.3 months after exposure “window period “ (2) Following this period HIV test became positive. Q. How do you confirm the diagnosis ?

43. A. @ PCR @ Western blot Q. What is the family of HIV?

44. A. Retroviruses

45. Problem 7 (1) A 4-years old boy with skin rash, fever, running nose, cough, & Koplik's spots. Final diagnosis was measles. Q. How can the diagnosis be confirmed ?

46. A.@ Collect throat swab for virus culture @ Collect blood for serology Q. Is measles preventable?

47. A.By a live attenuated vaccine incorporated in MMR (measles-mumps- rubella) Given at 12-18 months of age

48. Problem 8 (1) An 8-year old girl with itchy skin rash, vesicles,& mild fever. Final diagnosis was chicken-pox. Q.Give the aetiology & how can you confirm diagnosis ?

49. A.@ Varicella-zoster virus (VZV) @ Confirmation by isolation of virus from vesicles fluid Or by serology

50. (1) A 48-year old man with painful skin rash localized on back & chest. Final diagnosis was herpes zoster (shingles – الحزام الناري ) that involves thoracic nerve roots. Q. What is the aetiology of this condition ?

51. A. Same VZV, in adults

52. Problem 9 (1) A 23-year old pregnant lady with fever, skin rash, & swelling of wrists. Final diagnosis was rubella. Q. What investigations should be carried out ?

53. A.@ Two sera for virus serology Q.How would you interpret the following : 1)Rubella IgG negative & IgM negative? 2)Rubella IgG negative & IgM positive? 3)Rubella IgG positive & IgM positive? 4)Rubella IgG positive & IgM negative?

54. A. 1.No infection & no immunity 2.Acute infection & no immunity 3.Acute infection & past exposure 4.No infection & immunity Q.How may rubella be prevented ?

55. A. Live attenuated vaccine with MMR vaccine, & given in 2 nd.year of life. Q.What other viruses causing skin rash in pregnancy ?

56. A. Parvovirus B19