Transmission of the Bluetongue Virus

Bluetongue virus (BTV) is not contagious and effective transmission occurs only when infective blood or tissue suspensions are inoculated parenterally ie via midge bites

The midge as the vector

Graphic of the virus cycle in the midge

Transmission through insects that are blood-feeders serve as vectors and are by far the most effective means of transmission. The disease is usually transmitted by biting female Culicoides midges.

Click on the image for a graphic of the cycle of transmission of BTV between midges and ruminants.

 

Animal products

Excretions and secretions from infected animals contain minimal concentrations of the virus and susceptible animals are quite resistant to oral infection. Animal products such as meat, milk and wool from infected farms, and even from infected animals can, therefore be regarded as harmless from an epidemiological point of view.

Semen from BTV-infected bulls collected during the viremic phase may be infective, and cows inseminated with such semen may also become infected .

In pregnant animals, the embryo or foetus can become infected transplacentally.

culicoides

Transmission through insects that are blood-feeders serve as vectors and are by far the most effective means of transmission.