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