Isolation of Porcine Deltacoronavirus from Pigs with Vomiting and Diarrhea

Abstract

A disease characterized by vomiting and diarrhea was observed in a farrow-to-finish farm in Yamagata Prefecture in January 2015. Sows and boars developed severe vomiting, diarrhea, and anorexia, while suckling piglets only developed diarrhea. No piglets died during this occurrence. Using reverse transcription polymerase chain reaction (RT-PCR), the porcine deltacoronavirus (PDCoV) genome was detected in all 13 fecal samples tested. However, the porcine epidemic diarrhea virus and transmissible gastroenteritis virus were not detected. PDCoV was isolated from the RT-PCR-positive samples inoculated onto LLC-PK1 cells originated from a pig kidney. The isolated virus has a high nucleotide identity at the spike (greater than 97%) and nucleocapsid (greater than 99%) regions with the U.S. and South Korean isolates available in GenBank. Serological surveillance using an immunofluorescent assay indicated that the infected sows had antibodies against the isolated virus for eight months following the occurrence. These data suggested that the diarrhea was associated with PDCoV infection. This is the first report in Japan describing the isolation of PDCoV from clinical diarrheal cases and its genetic characterization.