Blue Tongue Disease (BTD)
French: fièvre catarrhale du mouton; Spanish: lengua atul; African: bloutang.
This disease occurs in wild and stock ruminants due to infections with BTD virus that is transmitted in Africa mainly by Culicoides imicola, in Central Europe (new) by C. obsoletus, in the USA by C. variipennis, and in Australia by the C. schultzei group.
Symptoms of Disease
Characteristics are the name-giving blue tongue due to cyanosis (rather rare); severe nasal discharge; subcutaneous hyperemia; petechae; lacrymation; facial, mouth, udder, and lung edema; swollen lymph nodes; and typical foot lesions leading to general stiffness, abortion, torticollis, and death.
In sheep, death rate reaches 80 %, 3–5 % in cattle, and very low rates (if at all) occur in wild ruminants.