Bluetongue (BT) is a disease in ruminants caused by an Orbivirus that is transmitted by midges. There are at least 29 serotypes of Bluetongue virus (BTV). The virus reproduces in ruminants and in midges. Wageningen Bioveterinary Research conducts research on this disease.

Which animals are susceptible to bluetongue?

Infected midges naturally infect domestic and wild ruminants (for example, sheep, cattle, goats and deer) and camelids (such as the llama and alpaca) by bites during feeding. Cattle show higher and longer viraemia than sheep, but the disease is seen more frequently and more severe in sheep (depending on the serotype of BTV).

What are the symptoms?

The disease is characterized by inflammation of the mucus membranes around the mouth and nose, this inflammation causes the rarely seen 'blue tongue' that gives the disease its name.

Can people become infected?

Bluetongue does not affect humans so there are no public health implications.

Where does the bluetongue virus circulate?

Bluetongue occurs almost everywhere in the world. In Europe, the spread of Bluetongue virus was formerly associated to the presence of Culicoides imicola. In 2006 it became clear that BTV could also be spread by endemic species of Culicoides in Northern parts of Europe.

Is the Netherlands free of bluetongue?

After several years without new infections, the Netherlands, together with a number of other North-Western European countries, was officially declared free of bluetongue in 2012.

In Southern Europe there is great difficulty in getting the different serotypes of the virus under control, partly due to reintroductions from North Africa.

Restricted zones in Europe where different bluetongue virus serotypes are circulating (March 2021, source: OIE)
Restricted zones in Europe where different bluetongue virus serotypes are circulating (March 2021, source: OIE)

How can we prevent the spread?

The spread of bluetongue can be reduced by controlling midges. Local application of insect repellents is possible to reduce the risk of contamination.

Can animals be tested for bluetongue?

As the national reference laboratory of the Netherlands, Wageningen Bioveterinary Research can test animals for bluetongue. A suspicion can be refuted or confirmed. Healthy animals can also be tested to rule out bluetongue, for example for import/export, semen and ovum production and national animal transport.