Updated: 22/04/2002

BLUETONGUE

 Aetiology  Epidemiology  Diagnosis  Prevention and control  References 

AETIOLOGY

Classification of the causative agent

Virus family Reoviridae, genus Orbivirus. 24 serotypes have been identified.

Resistance to physical and chemical action

Temperature: Inactivated by 50C/3 hours; 60C/15 minutes
pH: Sensitive to pH <6.0 and >8.0
Chemicals: Inactivated by -propiolactone
Disinfectants: Inactivated by iodophores and phenolic compounds
Survival: Very stable in the presence of protein (e.g. has survived for years in blood stored at 20C)


EPIDEMIOLOGY

Hosts

Transmission

Sources of virus

Occurrence

The virus is present in a broad band of countries extending appriximately between 40N and 35S. The bluetongue virus has been shown by serology to be present in regions where the Culicoides vector is present (e.g. Africa, the Americas, Australia and some countries of southern Asia and Oceania). However, clinical disease with confirmation by virus isolation has been observed in a few countries only.

For detailed information on occurrence, see recent issues of World Animal Health and the OIE Bulletin


DIAGNOSIS

Incubation period is 5-20 days

Clinical diagnosis

Acute form (sheep and some species of deer)

Inapparent infection

Lesions

Differential diagnosis

Laboratory diagnosis

Procedures

Isolation of the agent

Identification of the agent

Serological tests

  • Competitive ELISA
  • Agar gel immunodiffusion
(prescribed tests in the Manual)
  • Virus neutralisation
  • Complement fixation

Samples

Isolation and identification of the agent

Serological tests

PREVENTION AND CONTROL

Sanitary prophylaxis

Medical prophylaxis


REFERENCES AND OTHER INFORMATION

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