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Pox Viruses
Hugh B. Fackrell
Fackrel@Uwindsor.ca
poxvirus.ppt
4/13/2015
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Pox Viruses
Structure
Classification
Multiplication
Clinical manifestations
Epidemiology
Diagnosis
Control
Baron’s Web Site
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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
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Multiplication
Attachment
 outer
membrane of infectious virion fuses with cell
membrane
Penetration
 outer
membrane remains with cell membrane
Uncoating
 yields
infectious intracellular virions
 via cellular enzymes
 exposes core proteins
 DNA dependent RNA polymerase
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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
Hep 2 cell line
Late Cytopathic Effect
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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
serotype
long incubation period
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
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Punch 1802 smallpox vaccine
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DONE!!!
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