Modification of PCR Program for Detection of Infectious Myonecrosis Virus

Infectious myonecrosis (IMN) causes high mortality in the white leg shrimp Litopenaeus vannamei and is listed by the OIE. In the current OIE manual (2016), a commercial kit is recommended to conduct one-step RT-PCR for the detection of IMNV. However, the reagent kit is no longer sold in Japan. We therefore tested different programs for RT-PCR using SuperScript Ill One-Step RT-PCR System, which is different from the one that is recommended in the OIE manual for the diagnosis of the disease. The sensitivity of virus detection was clearly higher when the program of 3-step PCR after reverse-transcription at 55 degrees C was adopted than the detection using the program described in the OIE manual, which is 2-step (shuttle) PCR after reverse-transcription at 60 degrees C. The result suggests that the 3-step PCR program with SuperScript Ill is useful for the diagnosis of IMN.