Viral Diseases I Flashcards
What are 4 ways that viruses can overcome the skin barrier?
- Trauma/ abrasions
- Arthropods (insects)
- Animal bites
- or Iatrogenic (caused by the vet)
How could you classify a pappilomavirus?
- Small
- Non-Enveloped
- not easily disinfected by organic detergents
- can survive low pH and high temperatures
What is the consequence of papillomavirus having double stranded DNA?
genome is infectious (they can replicate straight away)
What is the negative of the papillomavirus replication strategy?
It requires actively dividing cells
It onky has 8 genes so it requires hsot enzymes
At what part of the skin is the virus shed?
at the top (where skin is shed)
What do viruses induce in the skin?
Hyperplasia, Causing the skin cells to be produced more rapidly so the virus can move its way through the skin
What do papillomaviruses cause?
warts (benign neoplasms that usually regress spontaneously as the immune system recognises them as foreign)
What is the meaning of the DNA being episomal?
it replicates autonomously and is not integrated inti the host genome
What occurs when the papillomavirus progresses into malignancy?
Virus genome is then integrated into the host DNA
* thus the host cell is transformed (also known as malignant transformation)
* site of integration is random
In what species are papilloma warts most common?
Most common in cattle compared to any other species
What do pure papillomas (bovine papilloma) infect?
Only infect epithelial cells (keratinocytes)- squamous papillomas
What do fibropapillomas infect?
they infect keratinocytes, but also sometimes the underlying layers to cause fibropapillomas
What are the clinical signs of Bovine Papillomavirus?
Hyperplasia and hyperkeratinisation 4-6 wks after exposure
Then leading to- raised plaques, proliferating epidermis, pedunculated masses
these usually regress after 1-6 months
What are the clinical features of equine papillomavirus?
Warts/ sarcoids do occur and they are commonly associated with BPV-1 and BPV- 2
Sarcoid is the most common skin tumour of horses
(most common in horses less than 4 years old)
What are the most common papillomas in dogs?
The most common are oral papillomas in young dogs
they typically regress spontaneously in 8 weeks
they can very rarely progress to squamous cell carcinomas
