Serotypic identification of local Bluetongue virus isolates using Plaque Reduction Neutralization (PRN) and Reverse Transcriptase Polymerase Chain Reaction (RTPCR) Techniques

Bluetongue virus (BTV) is a vector-borne disease of ruminants disseminated in the tropics and sub-tropics. It is also an important problem in the Middle East. The purpose of this study is serotypic identification of local Bluetongue viruses (BTV) isolated between 1998 and 2005. For this purpose, generic (g) and serotype specific (s) RT-PCR systems and the Plaque Reduction Neutralization Assay (PRNA) were used. Generic and serotype specific RT-PCR was performed on the segment 10 and segment 2 levels, respectively. Generic RT-PCR applications revealed specific DNA product (822 bp in length) in all 26 BTV field isolates. On the other hand, 19 BTV isolates were identified as serotype 9 and one isolate was found to be serotype 16, using the sRT-PCR technique. No DNA amplification was observed as a result of sRT-PCR for serotypes 2 and 4. Plaque reduction and neutralization assay (PRNA) was used for serologic identification of BTV isolates. Hyperimmune serums specific to three serotypes (BTV-4, BTV-9 and BTV-16) produced in rabbits, were used in PRNA. The test showed that 19 of the isolates were BTV-9, and the remaining two isolates were identified as BTV-4 and BTV-16.