Pox Viruses by ert554898

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    Pox Viruses

             Hugh B. Fackrell

         Fackrel@Uwindsor.ca

                  poxvirus.ppt



                        4/12/2012
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                    Pox Viruses

    Structure
    Classification
    Multiplication
    Clinical manifestations
    Epidemiology
    Diagnosis
    Control
                Baron’s Web Site
                                   4/12/2012
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    Structure
    Brick shaped complex
     symmetry
       240nm   x 300 nm
    Enveloped
       antibody   neutralization sites
    Core contains enzymes for
     virus uncoating dsDNA
    Inner membrane
    Lateral bodies
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                         Smallpox virus




    negatively stained

                                 Thin section


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                   Pox Viruses




               Canary pox virus

    Vaccinia
                                  Orf virus

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             Pox Viruses of Vertebrates

    Orthopoxvirus
       smallpox, vaccinia, cowpox, camelpox,
          mousepox, racoonpox
    Parapoxvirus
         ORF( contagious pustuular dermatitis,
          pseudocowpox, bovine papular stomatitis
    Capripoxvirus
       sheeppox,   goatpox, lumpy skin disease

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                     More Pox Viruses

Avipoxvirus
Fowlpox
     canarypox,pigeonpox,   fowlpox
Leporipoxvirus
       myxoma, hare fibroma, rabbit fibroma,squirrel fibroma
Suipoxvirus
     Swinepox

Unclassified
     molluscum   contagiosum, Tana, Yaba            4/12/2012
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                        Multiplication
Attachment
          membrane of infectious virion fuses with cell
     outer
      membrane
Penetration
     outer   membrane remains with cell membrane
Uncoating
     yields infectious intracellular virions
     via cellular enzymes
     exposes core proteins
     DNA dependent RNA polymerase                  4/12/2012
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    Clinical manifestations

         Primary localized skin lesion
          e.g. cowpox
            usually on hand
            occasionally on face or
             genitals by scratches
         Generalized skin lesions e.g.
          small pox, molluscum
         Encephalitis is rare

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     Smallpox pustules




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     Burn infected with vaccinia




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     Vaccinia complications




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                    Host Defenses

     unbroken skin represents primary control
     Interferon, nonspecific inflammation
     Cell mediated immunity
     Humoral immunity- outer membrane
      antigens




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                      Diagnosis

     Clinical manifestations
     History of animal contact
     Electron microscopy of scab
      material
     Cell cultures
     Chicken embryos


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     Vaccina Cytopathic Effect


                           Human
                           amnion
                           cell line




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                    Chick Embryo Lesions




     Infected egg
                                Healthy egg
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     Vaccinia lesions on Chorio
        allantoic membrane




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           Cytopathic Effect of Vaccinia




 Early Cytopathic effect                 Late Cytopathic Effect

                       Hep 2 cell line                    4/12/2012
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     Smallpox was global




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     Human Pox Viruses are acquired
        from animal reservoirs




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                           Control

     infection by zoonotic pox viruses is
      inevitable
        improved  health education
        break link with reservoir

     improved hygiene molluscum contagiosum




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             Eradication of Smallpox

 easily diagnosed       effective vaccine- only one
 long incubation period  serotype
 low communicability no long term immunity
  animal reservoir       high morbidity & mortality




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           Smallpox Eradication (cont)

     infectious only after incubation period
     no persistent infection
     subclinical infection rare and not a source
      of infections
     no cultural and social barriers
     feasbility of elmination shown in
      developing countries
     save surveillence costs in nonendemic
      developed countries                       4/12/2012
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     Punch 1802 smallpox vaccine   4/12/2012
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     DONE!!!




               4/12/2012

								
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