Bluetongue disease, also known as catarrhal fever, is an insect-borne viral disease of ruminants like sheep, goats, cattle, deer, buffalo, antelope and dromedaries. The disease is not contagious and no reports of human transmission have been documented.

There is no known treatment for bluetongue disease. Preventive measures include vaccination, quarantine, vector control and inoculation.

Major symptoms of bluetongue include face and tongue inflammation, excessive salivation, high fever and tongue cyanosis. The swelling of the tongue and lips result in the blue appearance of the sufferer’s tongue. Some animals may suffer from nasal symptoms, stertorous respiration and nasal discharge. Others develop foot lesions, which may eventually lead to knee walking (in sheep). Cattle with this condition change their feet position constantly, making it popular as “the dancing disease”. Some animals don’t show any symptoms, but the ones infected severely could die as fast as a few days. Those who are treated, however, recover extremely slow for up to several months.

The pathogenic virus BTV (Bluetongue virus) from the genus Orbivirus causes this condition. It is transmitted by various culicoids like Culicoides imicola.