Fig. (4) Sensitivity of established RT-PCR. Total RNA of VR-2332 (A), JXA1 (B) and HNjz15 (C) were isolated from the infected cells. One microgram RNA was reverse-transcribed and cDNA were serially (10×) diluted to be used as the template for PCR amplification. The bottom limit of RT-PCR detection was expressed by the visualized bands on 2% agarose gel electrophoresis.