Basics of Bluetongue

About The Disease
Bluetongue is a non-contagious viral disease which is transmitted by vector, in this case tiny midges, most commonly found in late summer and autumn. Bluetongue is a disease of animals affecting all ruminants, including sheep, cattle, deer, goats and camelids (camels, llamas, alpacas, guanaco and vicuña). It does not affect horses or pigs. Due to the vector transmission any infected animal must be slaughtered immediately, but culling of the heard is an ineffective method of disease control as bluetongue non-contagious.

Symptoms

-Drooling

-Swelling of the head and neck
-Conjunctivitis  
-Swelling of the mouth
-Swollen teats
-Tiredness

The Virus (BTV)

Bluetongue virus causes serious disease in a lot of livestock. Partly due to this BTV has been in the forefront of molecular studies for last three decades and now represents one of the best understood viruses at the molecular and structural levels. BTV, like the other members of the family is a complex non-enveloped virus with seven structural proteins and a RNA genome consisting of 10 double-stranded (ds) RNA segments of different sizes.

Treatment and Prevention

There is no efficient treatment. Prevention is effected via quarantine, inoculation with live modified virus vaccine and control of the midge vector, including inspection of aircraft.
However, simple husbandry changes and practical midge control measures may help break the livestock infection cycle. Housing livestock during times of maximum midge activity (from dusk to dawn) may lead to significantly reduced biting rates. Similarly, protecting livestock shelters with fine mesh netting or coarser material impregnated with insecticide will reduce contact with the midges. The Culicoides midges that carry the virus usually breed on animal dung and moist soils, either bare or covered in short grass. Identifying breeding grounds and breaking the breeding cycle will significantly reduce the local midge population. Turning off taps, mending leaks and filling in or draining damp areas will also help dry up breeding sites.