The virus attacks sheep and cattle, along with other livestock, causing fevers, ulcers, a swollen head and lameness. In severe cases the tongue turns blue and can swell enough to protrude from the mouth, sometimes killing the animal. Biting midges carry the disease, and it has spread as far north as Aberdeenshire.
Bluetongue originated in Africa and has pushed into Europe over the past two decades. The World Organisation for Animal Health links that spread to climate breakdown, as warmer conditions let the midges that carry the virus survive and travel farther than before. The strain now hitting British farms, serotype 3, marks a new front for the disease.
For farmers, the outbreak means watching herds and flocks for symptoms that can turn deadly fast. There's no easy way to stop midges from biting. Livestock losses hit income directly, and a disease spreading this far north suggests the problem is not going away soon. Farms that have never dealt with bluetongue before now have to plan for it.