Monovalent inactivated bluetongue virus type 1 vaccine induced neutralising antibody response in sheep

Bluetongue (BT) is a non-contagious, infectious and economically important vector-borne viral disease mainly of sheep and other domestic and wild ruminants. In the present study, binary ethylenimine (BEI) inactivated saponified bluetongue virus type 1 (BTV1) vaccine was developed and evaluated for efficacy in adult non-descript indigenous seronegative sheep. Sheep were vaccinated with primary and booster doses of the inactivated vaccine at an interval of 21 days followed by challenging the animals with infective virus. There was a slight increase (2 to4ºC) in body temperature in all the vaccinated animals and it persisted for 4 to 5 days. Vaccine produced slight to moderate local inflammatory response at the site of inoculation. Significant humoral immune response was observed in all the vaccinated animals as revealed by the presence of neutralizing antibodies (titre of 1: 512). Post challenge viraemia of shorter duration was detected in vaccinated animals compared to that of the control. The vaccine was found to be safe, potent and highly effective in conferring protection against BTV1 infection in indigenous sheep.