In the last three months of 1998, there was an outbreak of bluetongue in the Union, on the Greek islands of the south-eastern Aegean. This is a viral disease transmitted by insects of the genus Culicoides. It results in disease and appreciable mortality among sheep.
Cattle are asymptomatic carriers of the virus, but are involved in the disease's life cycle.
This disease poses a serious threat to the Community herd. Nevertheless, the Directive is not well adapted to the fight against bluetongue, because of the disease's specific epidemiological profile. Its measures are, in the main, well suited to combating bluetongue. The purpose of this Directive is to adopt for bluetongue the provisions introduced to control African horse sickness, making whatever amendments are necessary for the target species' specific characteristics. To prevent infestations by the vectors as far as possible, the rate of treatment shall be fixed by the competent authority, taking account of the persistence of the insecticide used and the climatic conditions.