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| − | {{unfinished}}
| + | #REDIRECT[[:Category:Papomaviridae]] |
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| − | {{toplink
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| − | |linkpage =Viruses
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| − | |linktext =VIRUSES
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| − | |pagetype =Bugs
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| − | }}
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| − | <br>
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| − | =Introduction=
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| − | Papillomaviruses infect keratinized cells, giving rise to sarcoids, warts, and papillomas.
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| − | =Morphology=
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| − | *Medium-sized, icosahedral, non-enveloped dsDNA viruses
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| − | =Virulence and Pathogenesis=
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| − | *Target actively-dividing cells
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| − | *Warts: genes expressed are associated with '''transformation''' (hyperplasia and delayed maturation)
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| − | *Virus is shed as cells exfoliate
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| − | *Oral papillomas in young animals often resolve spontaneously
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| − | =Epidemiology=
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| − | *'''Resistant''' viruses: can persist in environment for months
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| − | *Restricted to stratified squamous and mucosal epithelia with slow growth
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| − | *Usually species specific
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| − | =Types and Subtypes=
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| − | =Virus by Species=
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| − | ===Canine Papillomavirus===
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| − | *Occur in oropharynx of puppies aged 4-6 weeks
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| − | *Usually resolve spontaneously
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| − | ===Bovine Papillomaviruses===
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| − | *2 groups:
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| − | #Fibropapillomas: viral DNA sequences, but no virus found | |
| − | #Epithelial Papillomas: virus found
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| − | *Calves most commonly affected
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| − | *Usually resolves spontaneously
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| − | *Can undergo malignant transformation to alimentary carcinomas
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| − | **Usually concurrent with grazing bracken (co-carcinogen) and ingesting quercetin (immunosuppressant)
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| − | *Can cause squamous cell carcinoma of the eye in Hereford cattle, where UV light acts as the co-carcinogen
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| − | ===Equine Papillomaviruses===
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| − | *Occurs in horses aged 1-3 years
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| − | *Muzzle, oral cavity
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| − | *Spread by direct contact
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| − | *Virus persists giving life long immunity and antibody-detection
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| − | *Usually resolves spontaneously but can be treated by laser or cryo-freezing
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| − | ===Equine Sarcoids===
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| − | *Most common '''untreatable tumor'''
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| − | *Locally aggressive tumor of integument
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| − | *Associated with Arabs and Thoroughbreds
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| − | *Thought to be associated with '''bovine papillomaviruses'''
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| − | *Virus entry through skin abrasions
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| − | *Flies may act as mechanical vectors
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