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==Description==

==Description==

Bluetongue is a non-contagious, arthropod-borne disease of ruminants, caused by bluetongue virus (BTV). Sheep are particularly badly affected, and often suffer a cyanotic tongue which lends the disease its name. The virus has been isolated from hosts worldwide (excluding Antartica)¹, despite being initially recognised in Africa in the late 19th and early 20th centuries². Although BTV's transmission and epidemiology is dependent on insect vectors, bluetongue greatly influences the global trade of ruminants as it is included on the Office International des Epizooties List A of animal diseases³. Originally thought to be a disease of tropical and sub-tropical regions, bluetongue has shown a propensity to become established in temperate areas, and in recent years has spread North, through the Mediterranean Basin, to become endemic in many European countries including the UK.

Bluetongue is a non-contagious, arthropod-borne disease of ruminants, caused by bluetongue virus (BTV). Sheep are particularly badly affected, and often suffer a cyanotic tongue which lends the disease its name. However, cattle are the main reservoir of disease. The virus has been isolated from hosts worldwide (excluding Antartica)¹, despite being initially recognised in Africa in the late 19th and early 20th centuries². Although BTV's transmission and epidemiology is dependent on insect vectors, bluetongue greatly influences the global trade of ruminants as it is included on the Office International des Epizooties List A of animal diseases³. Originally thought to be a disease of tropical and sub-tropical regions, bluetongue has shown a propensity to become established in temperate areas, and in recent years has spread North, through the Mediterranean Basin, to become endemic in many European countries including the UK.

==Aetiology==

==Aetiology==