Clinical signs

On this page you can find short summaries of clinical signs in the main species affected by the Bluetongue virus

The BVA, British Cattle Veterinary Association, Goat Veterinary Society, Sheep Veterinary Society and Veterinary Deer Society urge all ruminant owners, shepherds and veterinary surgeons to be vigilant and to make themselves aware of the clinical signs of disease. Suspicion of disease should be reported to your local Animal health office.

Clinical signs of Bluetongue

Veterinary surgeons should be aware that sheep are showing clinical signs but less typically, cattle in the Netherlands have also shown clinical signs. European ruminants are naïve to the virus and there is little data on the disease in indigenous cattle and sheep. It is known that there is variation in clinical signs and severity between sheep breeds.

Sheep - signs of infection

These vary in severity depending on the strain of virus and breed of sheep. Clinical signs include

fever (typically ~42 ºC)
swelling of the head and neck
inflammation and ulceration of the mucous membrane of the mouth, nose and eyelids
lameness
muscle degeneration and leaking of blood or serum from blood vessels into the surrounding tissues
haemorrhages in the skin and other tissues
respiratory signs such as froth in the lungs and an inability to swallow
a high mortality rate

Sometimes, although it is rare, there may be some discolouration and swelling of the tongue. Differential diagnoses include Foot and Mouth Disease (FMD), Contagious Ovine Digital Dermatitis (CODD) and Photosensitivity.

Cattle - signs of infection

Although Bluetongue usually causes no apparent illness in cattle or goats, cattle are displaying clinical signs during the current outbreak in Western Europe. Cattle may

be febrile and may show dullness
exhibit nasal discharge, lachrymation, with swelling and erosion of the nasal planum, mouth and teats
show lameness due to coronitis

Differential diagnosis includes Foot and Mouth Disease (FMD), , Malignant Catarrhal Fever and Mucosal disease.

Other ruminants - signs of infection

Although goats, deer and camelids may carry the virus it may be mild or inapparent, with only a transient viraemia. Goat keepers should be aware that, in 2007, similar symptoms to those seen in sheep were reported.