Bluetongue virus serotype-1 in goats in the Pithoragarh area of Uttarakahand, India.

Abstract

This short communication reports the results of a bluetongue sero-surveillance conducted in the Pithoragarh hills of Uttarakhand in India during the autumn of 2011. Unclotted blood and serum samples were collected from 51 goats for detection of bluetongue virus (BTV) antigen and antibodies. Of the 51 collected samples, 18 (35%) were positive to an indirect ELISA and 33 (64%) resulted positive to a BTV ELISA antigen. From a strong antigen-positive blood sample, a BTV was isolated (named as PTG-13) on cell culture and was subsequently confirmed as BTV-1 by RT-PCR and partial sequencing of genome segment-2. The goat serum samples were found to contain high titer of neutralising antibodies against BTV-23, nonetheless the virus could not be isolated. Interestingly, no neutralizing antibodies were detected against PTG-13 or other BTV-1 isolate, which suggests that sampling was probably done before the development of neutralizing antibodies against PTG-13 virus in the host. Isolation of BTV-1 (PTG-13) and presence of BTV-23 neutralizing antibodies in serum samples indicate that goats were probably infected with BTV-1 and 23 in different periods.