Viruses

894 views

Published on

This is a series of lectures on microbiology, useful for medical and paramedical students

Published in: Health & Medicine
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
894
On SlideShare
0
From Embeds
0
Number of Embeds
65
Actions
Shares
0
Downloads
32
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • <number>
  • Viruses

    1. 1. VIRULOGY - INTRODUCTION Dr. Ashish V. Jawarkar, M.D. (Path) 1
    2. 2. 2
    3. 3. 3
    4. 4. History  Louis Pasteur was the first to suspect that organisms smaller than bacteria existed 4
    5. 5. 5
    6. 6. Viral diseases      Common cold Rabies AIDS Influenzae SARS 6
    7. 7. Morphology  Size –   Ultramicroscopic Seen only by electron microscope 7
    8. 8. 8
    9. 9. Size of viruses 9
    10. 10. 10
    11. 11. The Viral Structures and Shape 11
    12. 12.    Central nucleic acid (DNA or RNA) Capsid May / may not have outer covering 12
    13. 13. Capsids    All viruses have capsids- protein coats that enclose & protect their nucleic acid Each capsid is constructed from identical subunits called capsomers made of protein 2 types:   helical iscosahedral 13
    14. 14. Shape of Viruses, determined by the arrangement of proteins (capsomers) in the capsid 14
    15. 15. Helical 15
    16. 16. Icosahedral 16
    17. 17. Additional Structures in some Viruses, envelope and surface proteins 17
    18. 18. Function of the envelope 18
    19. 19. Naming viruses      No taxa above Family (no kingdom, phylum, etc) 19 families of animal viruses Family name ends in -viridae , Herpesviridae Genus name ends in -virus, Simplexvirus Herpes simplex virus I (HSV-I) 19
    20. 20. EXAMPLE of VIRAL TAXONOMY     Family – Herpesviridae Genus – Varicellovirus Common name – chickenpox virus Disease - chickenpox 20
    21. 21. VIRAL REPLICATION 21
    22. 22. Phage Replication 22
    23. 23. 6 steps in phage replication 1. 2. 3. 4. 5. 6. adsorption – binding of virus to specific molecule on host cell penetration –genome enters host cell replication – viral components produced assembly - viral components assembled maturation – completion of viral formation release – viruses leave cell to infect other cells
    24. 24. Fig 6.11 24
    25. 25. Penetration 25
    26. 26. Bacteriophage assembly line 26
    27. 27. Impact of Bacteriophages    Not all bacteriophages lyse cells Temperate phages insert their viral DNA into the host chromosome & viral replication stops at there until some later time. Lysogeny- bacterial chromosome carries phage DNA 27
    28. 28. Types of viruses DNA and RNA viruses replicate in different manner. 28
    29. 29. The Most Common DNA Viruses        Adenoviruses Cytomegalovirus Epstein-Barr virus Hepatitis B virus Herpes simplex Types 1 &2 Papovavirus Varicella-Zoster virus 29
    30. 30. The RNA Viruses              Dengue viruses Ebola virus Picorna viruses Hanta virus Hepatitis A and C HIV Influenza virus Mumps virus Norwalk virus Corona virus Rotavirus Rubeola Virus RSV 30
    31. 31. VIRAL CPE 31
    32. 32. Cytopathic effects- virusinduced damage to cells 1. 2. 3. 4. 5. 6. 7. changes in size & shape cytoplasmic inclusion bodies nuclear inclusion bodies cells fuse to form multinucleated cells cell lysis alter DNA transform cells into cancerous cells 32
    33. 33. Cytopathic changes in cells 33
    34. 34. Inclusion body 34
    35. 35. Transformation or conversion of cell division to cells that divide indefinitely ( tumors ,warts) Induces hyperplasia of the host cells 35
    36. 36. Host Response to Viral Infections 36
    37. 37.  Host Cell response includes :  Antibody response  Cellular Immune response  Interferon production 37
    38. 38. Antibody Response 38
    39. 39. Cellular Immune response 39
    40. 40. Interferons 40
    41. 41. Diagnostic Virology 41
    42. 42. How do we grow viruses? Obligate intracellular parasites require appropriate cells to replicate.
    43. 43. Growing animal viruses 1. 2. 3. live animals bird embryos – chicken, duck; intact, self-supporting unit, sterile, selfnourished cell culture- cell lines 43
    44. 44. Virus laboratory 44
    45. 45. Cell Culture   Cell culture is the process by which prokaryotic, eukaryotic or plant cell are grown under controlled conditions. "cell culture" now , refers to the culturing of cells derived from multicellular eukaryotes, especially animal cells. 45
    46. 46. Cell lines  Cells that are cultured directly from a subject are known as primary cells.    primary cell cultures have limited lifespan after a certain number of population doublings cells undergo the process of senescence and stop dividing, while generally retaining viability. An established or immortalised cell line has acquired   the ability to proliferate indefinitely either through random mutation or deliberate modification, such as artificial expression of the telomerase gene There are numerous well established cell lines representative of particular cell types. 46
    47. 47. Established human cell lines   One of the earliest human cell lines, descended from Henrietta Lacks, who died of cervical cancer . The cultured HeLa cells shown below have been stained with Hoechst turning their nuclei blue. 47
    48. 48. Tissue Culture 48
    49. 49. Tissue Culture 49
    50. 50. No virus virus 50
    51. 51. Egg Inoculation 51
    52. 52. Egg inoculation … 52
    53. 53. Diagnosis of viral diseases    More difficult than other agents Consider overall clinical picture Take appropriate sample    Infect cell culture- look for characteristic cytopathic effects Screen for parts of the virus Screen for immune response to virus (antibodies) 53
    54. 54. diagnosis 54
    55. 55. Thank you end of lecture ! 55

    ×