Detection of PCV2e strains in Southeast China

Jiankui Liu; Chunhua Wei; Ailing Dai; Zhifeng Lin; Kewei Fan; Jianlin Fan; Jiayue Liu; Manlin Luo; Xiaoyan Yang

doi:10.7717/peerj.4476

Detection of PCV2e strains in Southeast China

PeerJ. 2018 Mar 27:6:e4476. doi: 10.7717/peerj.4476. eCollection 2018.

Authors

Jiankui Liu^{1

2}, Chunhua Wei^{1

2}, Ailing Dai^{1

2}, Zhifeng Lin^{1

2}, Kewei Fan^{1

2}, Jianlin Fan^{1

2}, Jiayue Liu^{1

2}, Manlin Luo³, Xiaoyan Yang^{1

2}

Affiliations

¹ College of Life Sciences, Longyan University, Longyan, China.
² Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Longyan University, Longyan, China.
³ College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.

Abstract

Porcine circovirus 2 (PCV2) has been prevalent in swine herds in China since 2002, causing severe economic loss to the pig industry. The number of live pigs in southeast China is > 20 million. Since information on the genetic variation of PCV2 in the Fujian province is limited, the objective of the present work was to investigate the epidemiological and evolutionary characteristics of PCV2 in southeast China from 2013 to 2017. Of the 685 samples collected from 90 different swine herds from 2013 to 2017, 356 samples from 84 different swine herds were positive for PCV2. PCV2a, PCV2b, PCV2d, and PCV2e co-existed in the Fujian province, with PCV2d being the predominant circulating strain in swineherds and PCV2e being reported for the first time in China. Strikingly, PCV2-FJ-water DNA comes from contaminated river water and not infected animals. Sequence comparison among all isolates indicated that 95 isolates shared approximately 78.7%-100% nucleotide identity and 74.5%-100% amino acid identity for open reading frame 2 (ORF2). Amino acid alignment showed that the Cap protein of PCV2e differed markedly from those of PCV2a, PCV2b, PCV2c, and PCV2d. These results indicated that various PCV2 genotypes exist in China, and that PCV2 is continuously evolving, leading to rapid emergence of new variant stains.

Keywords: Genotype; PCV2; Phylogenetic analysis; Recombination.

Grants and funding

This work was supported by Major Project of the Science and Technology Program of Fujian Province, China (2014NZ0002-3), the Fujian Natural Science Foundation, Fujian Province, China (2016J01168), and the Collaborative Innovation Center of Animal Health and Food Safety Application Technology in Fujian, Fujian Vocational College of Agriculture (Dongxie 201701). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.