Papillomaviruses

Question 1

What are the features of Papillomaviruses

Answer 1

• Non enveloped
• DS-DNA viruses
• Icosahderal symmetry
• Highly environmentally resistant
  Highly resistant to many solvents
  HOST SPECIFIC - not contagious between species
  Epitheliotrophic
  Unable to be cultured in the lab

Question 2

What are the host viral interactions of papillomaviruses

Answer 2

Contagious within the species of disease
Only Bovine P 1 and 2 exhibit broader host range and tissue tropism —> fibropapillomas in cattle and sarcoidosis in horses

Question 3

Describe the pathogenesis of warts of P virus

Answer 3

Mostly hyper plastic or benign neoplasia
Can undergo malignant transformation in some species
Actively dividing basal cells of squamous epithelium infected by skin abrasion
Early gene expression in infected cell causes hyperplasia of epithelium, delayed maturation and massed into papilloma
Virions accumulate in epithelial and shed in exfoliated cells
Facilitates spread of virus between host of same species

Question 4

What hosts are most commonly infected and does the virus regress

Answer 4

Young animals with actively dividing cells are most commonly affected
The disease usually regresses spontaneously after weeks or months
Regression attributed to cell mediated immunity
Once recovered, often immune to re-infection