Sequence analysis of the spike gene of Porcine epidemic diarrhea virus isolated from South China during 2011–2015

Zhao, Xiaoya; Li, Zhili; Zeng, Xiduo; Zhang, Guanqun; Niu, Jianqiang; Sun, Baoli; Ma, Jingyun

With the exception of the CH-YGC-11-2013 and CH-XLC-03-2013 strains, the remaining 53 South China strains contained several amino acid substitutions compared with the vaccine strains, resulting in changes in the amino acid constitution of the SS6, 2C10, and COE neutralizing epitopes. A retrospective study of the three amino acid substitutions revealed that the shift process was present not only in European strains but also in Asian PEDV strains [8] . Those results in combination with our results indicate that the three substitutions represent a marker of increased PEDV viability [8] . The domestic outbreak of PED in China was caused by new PEDV strains, the S genes of which had similar molecular characteristics [7] . According to previous studies as well as the present study, the epidemic strains of PEDV have a close genetic relationship with Asian strains including those isolated in China, Korea, and Japan after 2010 [2, 15, 20] . Therefore, a detailed description of the differences between epidemic strains and vaccine strains could aid in the development of improved vaccines against PEDV.