Viral Disease

1. Viral Disease Slackers Facts by Mike Ori

2. Disclaimer The information represents my understanding only so errors and omissions are probably rampant. It has not been vetted or reviewed by faculty. The source is our class notes. The document can mostly be used forward and backward. I tried to mark questionable stuff with (?). If you want it to look pretty, steal some crayons and go to town. Finally… If you’re a gunner, buck up and do your own work.

3. What are the three types in Orthomyxoviruses

4. A, B, C

5. Seasonal flu is what type?

6. Type A

7. Describe the genome of orthomyxovirus

8. Segmented ssRNA (-)

9. To what do H and N refer to

10. Hemagglutinin and neuraminidase spikes on the viral surface

11. In which portion of the cell orthomyxovirus replicate and why?

12. In the nucleus because they cannot prime their RNA strands

13. Why is the seasonal flu shot seasonal?

14. A new vaccine is required each year because of antigenic drift due to polymerase errors

15. Why does bacterial pneumonia often follow influenza?

16. The virus causes destruction of ciliated respiratory epithelium in the upper respiratory tract. This degrades the mucociliary elevator and prevents efficient clearance of bacteria. General immune system down regulation occurs as the influenza infection is controlled.

17. What is the basis for the increased virulence seen in H1N1 of swine origin

18. Antigenic shift has substantially altered the virus to reduce its antigenic similarity to previous strains and to allow it to replicate in both the upper and lower respiratory tract.

19. Why are people over 50 less likely to get sick from H1N1 swine origin.

20. An similar pandemic occurred within their lifetime. They do not have as robust an immune system and cannot generate as much of a cytokine storm

21. Why is avian flu H5N1 difficult to get

22. Currently the strain’s H antigen interact with sialic acid alpha 2,3 gal receptors which are situated in the lower respiratory tract. Thus it take larger exposures to transmit the disease.

23. What would occur if H5N1 reassorts in swine

24. Why are swine important intermediates in the assortment of avian and human influenza?

25. Swine upper respiratory epithelium contains sialic a2,3 gal and sialic a2,6 gal receptors thus they can be easily coninfected with both human and avian virus. This allows nature to tinker. Idle goddesses are the devils workshop.

26. What will happen if H5N1 reassorts or mutates to efficiently infect both upper and lower respiratory epithelium.

27. The potential for significant mortality

28. What are the requirements of a pandemic influenza

29. New human type A strain Causing serious illness Easily spreads person to person

30. What diseases are caused by paramyxovirus

31. Mumps Parainfluenza and croup Rubeola (5 day measles) Respiratory syncitial virus

32. Describe the paramyxovirus spikes

33. Combined H and N on single spike (para=next to hence H is para to N) Fusion (F) protein on second spike

34. What is a syncitia and why do they form

35. A syncitia is a giant cell that forms by fusion of multiple cells. Paramyxovirus tends to form syncitia through the action of F protein deposited on cell surfaces.

36. Distinguish parainfluenza from Respiratory syncitial virus

37. Parainfluenza = bronchitis RSV = bronchiolitis

38. Describe RSV epidemiology

39. Occurs from the late fall to the spring. Predominantly affects small children < 1 yo.

40. Describe RSV immunity

41. Immunity is incomplete. Repeated infections occur with lessened severity but its unclear if there is an immune basis.

42. RSV diagnosis

43. Immunofluorescence of nasal swabs

44. RSV prophylaxis

45. Injection of monoclonal antibody against factor F is indicated in high risk children

46. Its flu if?

47. It looks like a cold but also has Myalgia/arthralgia Fever

48. Adenovirus structure

49. Linear dsDNA

50. Adenovirus disease