Direct and rapid detection of porcine epidemic diarrhea virus by RT-PCR.

To establish a practical method for detecting porcine epidemic diarrhea virus (PEDV), the use of primers derived from sequences that amplify the M protein genes of PEDV in a RT-PCR detection system was investigated. Primers were designed to amplify a 854-bp fragment by RT-PCR. This reaction was specific to the PEDV RNA but not to that of other viral genera tested. In experiments with mixtures of PEDV and either small intestine or fecal homogenates, this method could detect efficiently the PEDV RNA from samples containing very low numbers of virus (100 TCID50/sample) within 8 h. With specimens collected from swine breeding farms with the diarrhoeal disease, the PEDV RNA was detected in four intestine specimens out of 11 specimens. The result was in close agreement with the results of virus isolation and streptavidin-biotin technique for detecting PEDV and its antigens, suggesting that the RT-PCR assay would be useful method for practical application.