Adeno,Parvo,Polyoma Virus


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Adeno,Parvo,Polyoma Virus

  1. 1. Adenovirus, parvovirus, polyomavirus
  2. 2. Adenovirus
  3. 3. From Medical Microbiology, 5 th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 53-1. Adenovirus Structure
  4. 4. E1 E2 E4 E3 Late genes Adenovirus Genome 36 kb linear ds DNA Early genes for host and viral transcription control, viral DNA replication Late genes for virion structure
  5. 5. (From Fields Virology, 4th ed, Knipe & Howley, eds, Lippincott Williams & Wilkins, 2001, Fig. 67-5.) Adenovirus replication cycle
  6. 6. Adenovirus diseases
  7. 7. From Medical Microbiology, 5 th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005,, Fig. 50-4. Adenovirus pathogenesis
  8. 8. Summary: adenovirus <ul><li>Structure </li></ul><ul><ul><li>Medium sized (36 kb) dsDNA genome, naked capsid </li></ul></ul><ul><li>Pathogenesis </li></ul><ul><ul><li>respiratory or fecal oral transmission </li></ul></ul><ul><ul><li>replication in nucleus; moderately host dependent </li></ul></ul><ul><ul><li>local spread; viremia </li></ul></ul><ul><ul><li>cellular and humoral immunity important; virus encodes countermeasures against MHC I expression and apoptosis </li></ul></ul><ul><ul><li>direct cell damage from replication; respiratory illness, conjunctivitis, gastroenteritis, cystitis </li></ul></ul><ul><li>Diagnosis </li></ul><ul><ul><li>culture, viral antigen detection </li></ul></ul><ul><li>Treatment/prevention </li></ul><ul><ul><li>live military vaccine </li></ul></ul>
  9. 9. Parvovirus
  10. 10. Parvovirus structure
  11. 11. Parvovirus Genome 5 kb ssDNA, inverted terminal repeats (ITR) Rep gene required for DNA replication Cap gene encodes capsid proteins ITR ITR Rep Cap
  12. 12. Autonomous parvovirus replication
  13. 13. Helper dependent parvovirus (AAV) replication Infection without adenovirus Infection with adenovirus Superinfect with adenovirus Lytic replication AAV DNA integrates into chromosome 19
  14. 14. Parvovirus pathogenesis
  15. 15. Parvovirus pathogenesis
  16. 16. Parvovirus <ul><li>Structure </li></ul><ul><ul><li>Small (5 kb) linear ssDNA genome, naked capsid </li></ul></ul><ul><li>Pathogenesis </li></ul><ul><ul><li>respiratory transmission </li></ul></ul><ul><ul><li>replication in nucleus, very host dependent, needs S phase cells or helper virus </li></ul></ul><ul><ul><li>viremia </li></ul></ul><ul><ul><li>antibody important in immunity </li></ul></ul><ul><ul><li>targets erythroid lineage cells; fifth disease (symptoms immunological); transient aplastic crisis; hydrops fetalis </li></ul></ul><ul><li>Diagnosis </li></ul><ul><ul><li>serology, viral nucleic acid </li></ul></ul><ul><li>Treatment/prevention </li></ul><ul><ul><li>none </li></ul></ul>
  17. 17. Polyomavirus
  18. 18.
  19. 19. Polyomavirus genome
  20. 20. Replication cycle of polyomaviruses. Steps in the replication cycle are indicated by numbers as follows: 1, adsorption of virions to the cell surface; 2, entry by endocytosis; 3, transport to the cell nucleus (route and mechanism not yet known); 4, uncoating; 5, transcription to produce early region mRNAs; 6, translation to produce early proteins (T antigens); 7, viral DNA replication; 8, transcription to produce late region mRNAs; 9, translation to produce late proteins (capsid proteins); 10, assembly of progeny virions in the nucleus; 11, entry of virions into cytoplasmic vesicles (mechanism unknown); 12, release of virions from the cell by fusion of membrane vesicles with the plasma membrane; 13, released virion. Polyomavirus replication
  21. 21. Polyomavirus pathogenesis
  22. 22. Polyomavirus <ul><li>Structure </li></ul><ul><ul><li>Small (5 kb) circular dsDNA genome, naked capsid </li></ul></ul><ul><li>Pathogenesis </li></ul><ul><ul><li>respiratory transmission </li></ul></ul><ul><ul><li>replication in nucleus; very host dependent </li></ul></ul><ul><ul><li>viremia </li></ul></ul><ul><ul><li>persistence in kidneys; reactivation with immune compromise </li></ul></ul><ul><ul><li>inapparent infection; hemorrhagic cystitis; PML </li></ul></ul><ul><li>Diagnosis </li></ul><ul><ul><li>viral nucleic acid </li></ul></ul><ul><li>Treatment/prevention </li></ul><ul><ul><li>cidofovir ? </li></ul></ul>