Bluetongue virus

Question 1

Aetiology

Answer 1

• Orbivirusgenus of the Reoviridae family

Question 2

Epidemiology

Answer 2

• Allorbivirusesare arthropod-bourne, distributed byCulicoidesspp.
• Cattle are the reservoir and amplification hosts
• Endemic in tropical regions of the world where vectors are active year-round

Question 3

Clinical signs

Answer 3

• Cattle
  ◦ Fever up to (40.0ºC)
  ◦ Nasal discharge
  ◦ Swelling of the head and neck
  ◦ Conjunctivitis (runny eyes)
  ◦ Swelling/ulceration of the mouth
  ◦ Swollen teats
  ◦ Saliva drooling out of the mouth
  ◦ Abortion
• Sheep
  ◦ High rectal temperature
  ◦ Eye and nasal discharges
  ◦ Drooling (ulcerations in the mouth)
  ◦ Swelling of the mouth, head and neck
  ◦ Lameness (swelling coronary band)
  ◦ Difficulty breathing
  ◦ Abortion

Question 4

Diagnostics

Answer 4

• Clinicalexamination
• Virusidentification (cell culture & RT-PCR)
• Serologic testing(competitive ELISA & AGID)
• Post-mortemexamination
  ◦ haemorrhagic gingivitis
  ◦ cyanosis and multifocal haemorrhagic ulcerative glossitis
  ◦ hydrocephalus

Question 5

Treatment

Answer 5

• NSAIDs
• Supportive care for recumbent animals ( rehydration with isotonic fluids, antibiotic treatment ONLY if it is necessary for secondary infection)

Question 6

Prevention

Answer 6

• Limiting vector exposure during peak beating times (from dusk to dawn)
• Methods of controlling vector biting (synthetic pyrethroid) have shown limited efficacy
• Modified and inactivated vaccine in some parts of the world