To ensure the specificity of primers 261F and 261R, extracted DNA from 4 other DNA viruses that infect shrimp including WSSV, BP, IHHNV and HPV were used as a template for the PCR reaction.
No amplification was obtained with DNA extracted from these shrimp viruses (Fig. 2). In addition, primers 261F/R did not amplify shrimp DNA extracted from P. monodon. On the contrary, the specific amplification of the expected 261 bp fragment was observed when DNA extracted from MBV positive tissues was used as the template. The detection limit of the PCR method described here using primers 261F/R and cloned WS-1 plasmid DNA as the template revealed by agarose gel visualization that as few as 100 copies of template DNA could be detected using this one-step method (Fig. 3).