Viral Disease - Importance and Examples

Question 1

Why are viral diseases important?

Answer 1

• Rapidly mutate and continue to change
• Struggle to develop vaccines
• Difficult to treat without damaging host cells
• Economic impacts of culling sick animals

Question 2

Reasons for disease outbreaks

Answer 2

Population of susceptible individuals
Virus has evolved
* Previous immunity not working
Inadequate vaccines

Question 3

Reasons for individual being susceptible

Answer 3

Age
Failure of passive transfer
Unvaccinated
Country that isn’t usually exposed to disease

Question 4

Example of exotic disease in UK

Answer 4

Avian influenza

Question 5

Avian influenza

Answer 5

• Massive losses
• Affects poultry
• Can cause very rapid death - over night
  ○ Very sick individuals
• Rapid introduction of control measures
  ○ Aiming to eradicate virus from UK

Question 6

Example of endemic disease

Answer 6

Calf respiratory disease

Question 7

Calf respiratory disease

Answer 7

• Multifactorial disease
  ○ Bacteria also involved
• High cost on cattle farming

Question 8

Which viruses cause calf respiratory disease

Answer 8

○ Infectious Bovine Rhinotracheitis (IBR)
○ Bovine Respiratory Syncytial Virus (BRSV)
○ Parainfluenza virus - 3 (Pi3V)

Question 9

Reasons for calf respiratory disease

Answer 9

○ Mixing of age groups in a barn
○ Over stocking
○ Inadequate colostrum

Question 10

Examples of sporadic disease

Answer 10

Feline Parvovirus (FPV) (has vaccine)
Cat flu (has vaccine)
* Feline calicivirus (FCV)
* Feline Herpes Virus (FHV)
Feline Infectious Peritonitis (FIP)
* Sequel to Feline Enteric Coronavirus (FECV)
Malignant Catarrhal Fever

Question 11

Malignant Catarrhal Fever

Answer 11

• Seen in cattle
• Zoonoses from sheep
• Caused by Ovine Herpesvirus 2 (OHV2)
• Causes obvious disease
  ○ Very pyrexic
  ○ Corneal oedema
  ○ Marked discharge from nose and eyes
• Uncurable
• Fatal

Question 12

Economic importance of viruses

Answer 12

EXPENSIVE
○ Costs of loss of production
○ Culling costs
○ Banning of imports/exports
○ Control costs
Vaccination
Biosecurity

Question 13

Viral Zoonoses examples

Answer 13

Most are exotic to UK but may pose risk in future
○ Hantaviruses (rodent urine)
○ Louping ill (very rare, in sheep)
○ European Bat Lyssavirus (EBLV2)
○ Rabies

Question 14

Notifiable Viral diseases

Answer 14

Diseases of zoonotic/economic importance
* HPAI
* FMD
* Rabies