China Animal Husbandry and Veterinary Medicine ›› 2020, Vol. 47 ›› Issue (4): 1172-1182.doi: 10.16431/j.cnki.1671-7236.2020.04.023

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Molecular Epidemiological Investigation on ORF5 Gene of Porcine Reproductive and Respiratory Syndrome Virus in Sichuan in 2018

LIU Hanyang1, ZHANG Yi2, XIAO Ran3, CHEN Bin2, WU Yongsheng1, SU Zhipeng4, LI Yupeng5, PEI Chaoxin2, XU Zhenying1, ZHU Jiawen1   

  1. 1. Institute of Animal Science, Chengdu Academy of Agricultural and Forestry Sciences, Chengdu 611130, China;
    2. Sichuan Provincial Center for Animal Disease Control and Prevention, Chengdu 610047, China;
    3. Wuhan Center for Animal Disease Control and Prevention, Wuhan 430014, China;
    4. Sichuan Tequ Investment Group Co., Ltd., Chengdu 610207, China;
    5. College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
  • Received:2019-09-02 Online:2020-04-20 Published:2020-04-17

Abstract: In order to study the epidemic and evolution trend of porcine reproductive and respiratory syndrome virus (PRRSV) in Sichuan,this study took GP5 protein as the research object,detected 378 suspected PRRSV samples collected in different districts,cities and counties of Sichuan province in 2018 by Real-time PCR,and analyzed the nucleotide sequence and deduced amino acid sequence of ORF5 gene of some strains and predicted the N-glycosylation site.69 positive samples were detected by Real-time PCR,the positive rate was 18.25%.The ORF5 gene sequence analysis of 23 PRRSV strains showed that the nucleotide homology of ORF5 gene was 81.6%-100%,and the deduced amino acid homology was 81.4%-100%.All of them belonged to America type.Among them,1 strain belonged to subtype Ⅰ represented by the classic strain VR2332,17 strains belonged to subtype Ⅱ represented by the highly pathogenic strain JXA1,and 5 strains belonged to subtype Ⅲ represented by the recombinant strain NADC30,which indicated that there was genetic diversity of PRRSV epidemic strains in Sichuan province in 2018,HP-PRRSV was still the main epidemic strain,but there were still evolving classic strains.At the same time,recombinant strains which were similar to NADC30 and QYYZ began to appear.Through the analysis of amino acid mutation sites and N-glycosylation sites,it was found that 23 PRRSV strains had some mutations in two important epitope related areas and virulence related sites of GP5.It was speculated that these mutations might affect the virus’s escape from immune system and virus virulence,suggesting that in PRRSV prevention and control,genetic evolution analysis should be strengthened,and selected targeted vaccines and control strategies according to different types of strains.

Key words: porcine reproductive and respiratory syndrome virus (PRRSV); molecular epidemiology; ORF5 gene; variation analysis

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