Bluetongue in cattle, sheep and goat

Updated 10.04.2026

The Norwegian Veterinary institute monitor the situation of bluetongue on assignment from the Norwegian Food Safety Authority.

The aim of the surveillance programme for bluetongue is to document freedom from the infection in Norway according to the demands in Regulation (EC) No.1266/2007, Annex 1.1.2, and to contribute to the maintenance of this favourable situation.

Background

Bluetongue is a disease caused by Bluetongue virus (BTV) which comprises at least 26 serotypes (BTV 1-26). The virus is insect-borne and midges of genus Culicoides transmit BTV to susceptible ruminants, after being infected by feeding on viraemic animals. After replication in the insect’s salivary glands, which depends upon ambient temperature, the virus can be transmitted to new vertebrate hosts. Therefore, infection has a seasonal occurrence.

In 2006 an outbreak of bluetongue serotype 8 (BTV 8) started in the Netherlands and rapidly spread among the ruminant population in the European countries the following years. A surveillance programme for BTV 8 based on bulk milk serology was conducted in 2008. Four cattle herds in the southern part of Norway were seropositive for BTV 8. After two years of comprehensive monitoring and surveillance of BTV 8 without any further discovery of infected herds, Norway regained free status for bluetongue. The surveillance programme for BTV could be reduced to a small programme based on bulk milk serology.

The Norwegian Food Safety Authority is responsible for carrying out the surveillance programme for bluetongue. The Norwegian Veterinary Institute is in charge of designing the programme, collecting the bulk milk samples from the dairies and performing the tests.

2024

Bluetongue re-emerged in Norway in September 2024, the first outbreak since 2009. By the end of the 2024 vector season, 268 dairy herds in Southern Norway tested positive for antibodies against bluetongue virus in bulk milk samples. Vector actvity was recorded in Southern Norway until mid-November.