Porcine epidemic diarrhea (PED), caused by porcineepidemic diarrhea virus (PEDV), is a highly contagious, acute enteric viraldisease of swine characterized by vomiting, watery diarrhea, dehydration anddeath. To identify and characterize the field PEDVs associated with theoutbreaks of severe diarrhea in piglets in Jiangxi, 2013, the complete genomesequences of two representative strains of PEDV, designated CH/JX-1/2013 and CH/JX-2/2013, were determined andanalyzed. The genome sequences of both emergent Jiangxi PEDV strains, CH/JX-1/2013 and CH/JX-2/2013, were 28,038nucleotides in length excluding 3’ poly (A) tail. Compared to the PEDV CV777strain, CH/JX-1/2013 and CH/JX-2/2013 had someunique genetic characteristics in the proximal regionof the 5´-UTRs. Phylogenetic analysis of thecomplete genomes and the structural proteins revealed that CH/JX-1/2013 andCH/JX-2/2013 had a close relationship with post-2010 Chinese PEDV strains andUS strains identified in 2013. The nucleotide identity between the two Jiangxistrains (CH/JX-1/2013 and CH/JX-2/2013) and 30 strains of PEDV identifiedante-2010 and post-2010 ranged from 96.3-97.0% and 97.3-99.7%, respectively.Multiple nucleotide and deduced amino acid mutations were observed in theORF1a/b, S, ORF3, E, M and N genes among the current field PEDV strains when comparedto the CV777 strain. Some of the mutations altered the amino acid charge andhydrophilicity, and notably, there was an amino acid substitution in the middleof one neutralizing epitope (L1371I) of the S gene of both CH/JX-1/2013 andCH/JX-2/2013. Taken together, the accumulated genetic variations of the currentfield PEDV strains might have led to antigenic changes of the viruses, whichmight confer the less effectiveness or failure of the CV777-based vaccinescurrently being widely used in Jiangxi, China.

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jiangxi agricultural university; Jiangxi Academy of Agricultural Sciences