Using of real time PCR as a tool for quantification of sheep pox virus

| Sheep poxvirus (SPPV) is causing sheep pox clinical disease principally in sheep. In endemic areas, vaccination with live attenuated vaccines derived from SPPV provides protection from sheep pox disease. In current study, the evaluation of attenuated sheep pox virus vaccine was carried out in vitro by virus titration on tissue culture and in vivo by challenge test for vaccinated sheep to develop a rapid method to evaluate attenuated sheep pox virus vaccine using real time PCR compared to traditional method. Ten batches of commercial live attenuated sheep pox vaccines had been tested using the virus titration on tissue culture for quantification and real time PCR assay (qrt PCR) for identification and quantification of sheep pox virus in vaccine batches. It was found the minimal TCID50 that gave positive results of the qrt PCR for sheep pox virus was 1 TCID50/ sample. The efficacy of amplification was 1.99 with an R2 value of 0.991. The rt PCR gave results similar to tissue culture titration and statistical analysis showed a non significant difference (p > 0.05). These findings demonstrated the potential of rt PCR assay to supersede the traditional virus titration on tissue culture for identification and rapid evaluation of live attenuated sheep pox virus vaccines.