Viral Diseases I

Question 1

What are 4 ways that viruses can overcome the skin barrier?

Answer 1

• Trauma/ abrasions
• Arthropods (insects)
• Animal bites
• or Iatrogenic (caused by the vet)

Question 2

How could you classify a pappilomavirus?

Answer 2

• Small
• Non-Enveloped
• not easily disinfected by organic detergents
• can survive low pH and high temperatures

Question 3

What is the consequence of papillomavirus having double stranded DNA?

Answer 3

genome is infectious (they can replicate straight away)

Question 4

What is the negative of the papillomavirus replication strategy?

Answer 4

It requires actively dividing cells
It onky has 8 genes so it requires hsot enzymes

Question 5

At what part of the skin is the virus shed?

Answer 5

at the top (where skin is shed)

Question 6

What do viruses induce in the skin?

Answer 6

Hyperplasia, Causing the skin cells to be produced more rapidly so the virus can move its way through the skin

Question 7

What do papillomaviruses cause?

Answer 7

warts (benign neoplasms that usually regress spontaneously as the immune system recognises them as foreign)

Question 8

What is the meaning of the DNA being episomal?

Answer 8

it replicates autonomously and is not integrated inti the host genome

Question 9

What occurs when the papillomavirus progresses into malignancy?

Answer 9

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

Question 10

In what species are papilloma warts most common?

Answer 10

Most common in cattle compared to any other species

Question 11

What do pure papillomas (bovine papilloma) infect?

Answer 11

Only infect epithelial cells (keratinocytes)- squamous papillomas

Question 12

What do fibropapillomas infect?

Answer 12

they infect keratinocytes, but also sometimes the underlying layers to cause fibropapillomas

Question 13

What are the clinical signs of Bovine Papillomavirus?

Answer 13

Hyperplasia and hyperkeratinisation 4-6 wks after exposure
Then leading to- raised plaques, proliferating epidermis, pedunculated masses

these usually regress after 1-6 months

Question 14

What are the clinical features of equine papillomavirus?

Answer 14

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)

Question 15

What are the most common papillomas in dogs?

Answer 15

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

Question 16

What can you use to diagnose papillomavirus?

Answer 16

• PCR
• Immunohistochemistry
• Histopathology

Question 17

What is the definition of a papilloma?

Answer 17

small benign growth that originates in squamous cells

Question 18

What are ‘warts’?

Answer 18

Common name given to skin papillomas

Question 20

What are sarcoids?

Answer 20

equid specific, papillomas but go on to ulcerate and are defined as fibroblastic skin tumours

Question 21

What are fibropapillomas?

Answer 21

like sarcoids in other animals, they usually involve dermal fibroblasts

Question 22

What is the disadvantage of the papillomavirus replication strategy?

Answer 22

Requires actively dividing cells

Question 23

How many recognised types of Bovine Papillomavirus are there?

Answer 23

at least 10

Question 24

What type of papillomas only infect epithelial cells?

Answer 24

(3,4 and 6 Xipapillomavirus) also known as pure **papillomas **

Question 25

What type of papillomavirus infects keratinocytes and the underlying layers (1 and 2
Deltapapillomavirus)

Answer 25

Fibropapillomas

Question 26

What do bovine papillomas look like 4-6 weeks after exposure?

Answer 26

• Raised plaques
• Proliferating Epidermis
• Pedunculated masses

Question 27

When do bovine papillomas usually regress?

Answer 27

Usually regress spontaneously within 1-6 months but can then go on to ocassionally cause cancer

Question 28

Where are sarcoids in horses usually found?

Answer 28

• Head
• Ventral abdomen
• Limbs

Question 29

What can you use to confirm the presence of the virus within lesions?

Answer 29

Immunohistochemistry

Question 30

What can you use to diagnose and stage tumours?

Answer 30

Histopathology

Question 31

Why do papillomavirus’s not usually turn malignant?

Answer 31

DNA is episomal, replicates autonomously, and is not integrated into the host genome

tumour supressing genes are activated