title: US-like isolates of porcine epidemic diarrhea virus from Japanese outbreaks between 2013 and 2014.
abstract: Since late 2013, outbreaks of porcine epidemic diarrhea virus (PEDV) have reemerged in Japan. In the present study, we observed a high detection rate of PEDV, with 72.5 % (148/204) of diarrhea samples (suckling, weaned, and sows) and 88.5 % (77/87) of farms experiencing acute diarrhea found to be positive for PEDV by reverse transcription PCR. Sequencing and phylogenic analyses of the partial spike gene and ORF3 of PEDV demonstrated that all prevailing Japanese PEDV isolates belonged to novel genotypes that differed from previously reported strains and the two PEDV vaccine strains currently being used in Japan. Sequence and phylogenetic analysis revealed prevailing PEDV isolates in Japan had the greatest genetic similarity to US isolates and were not vaccine-related. Unlike vaccine strains, all prevailing field PEDV isolates in Japan were found to have a number of amino acid differences in the neutralizing epitope domain, COE, which may affect antigenicity and vaccine efficacy. The present study indicates recent PEDV isolates may have been introduced into Japan from overseas and highlights the urgent requirement of novel vaccines for controlling PEDV outbreaks in Japan.
authors.affiliation: Laboratory of Veterinary Pathology, Department of Veterinary, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, 889-2192 Japan.
authors.forename: Nguyen
authors.initials: N
authors.lastname: Van Diep
authors.affiliation: Laboratory of Veterinary Pathology, Department of Veterinary, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, 889-2192 Japan.
authors.forename: Junzo
authors.initials: J
authors.lastname: Norimine
authors.affiliation: Laboratory of Veterinary Pathology, Department of Veterinary, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, 889-2192 Japan.
authors.forename: Masuo
authors.initials: M
authors.lastname: Sueyoshi
authors.affiliation: Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
authors.forename: Nguyen Thi
authors.initials: NT
authors.lastname: Lan
authors.affiliation: Laboratory of Veterinary Pathology, Department of Veterinary, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, 889-2192 Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Hirai
authors.affiliation: Laboratory of Veterinary Pathology, Department of Veterinary, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki, 889-2192 Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Yamaguchi
keywords: ORF3; PED; PEDV Japan; Partial S gene; Porcine epidemic diarrhea virus