China Animal Husbandry and Veterinary Medicine ›› 2023, Vol. 50 ›› Issue (5): 2001-2011.doi: 10.16431/j.cnki.1671-7236.2023.05.027

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Variation Regularity and Transmission of PRRSV-2 Lineage 8 Strains in Guangdong and Surrounding Provinces

KANG Pu1,2, REN Zhaowen1, CAI Rujian1, LYU Zongji2, HUANG Yuhao3, WANG Xiaohu1   

  1. 1. Key Laboratory of Livestock Disease Prevention of Guangdong Province, Animal Epidemic Disease Field Science Observation and Research Station of Guangdong Province, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China;
    2. Foshan University, Foshan 528231, China;
    3. Dongguan Animal Disease Prevention and Control Center, Dongguan 523128, China
  • Received:2022-11-24 Online:2023-05-05 Published:2023-04-28

Abstract: 【Objective】 Bayesian phylodynamics was used to reconstruct the transmission and genetic evolution of Porcine reproductive and respiratory syndrome virus 2 (PRRSV-2) lineage 8 strains among five provinces:Guangdong,Guangxi,Hunan,Jiangxi and Fujian,providing a reference for targeted prevention and control of PRRS.【Method】 In this study,phylogenetic analysis of ORF5 sequences from all available PRRSV-2 strains from the above five provinces was performed,and lineage 8 strains were selected to eliminate recombinant sequences as well as suspicious sequences.The spatial data were combined with the evolution and epidemiological characteristics of pathogens for analysis,using BEAST and related software to calculate the common ancestor of the virus,nucleotide substitution rate,as well as possible transmission direction and migration rate between different geographical locations.【Result】 Phylogenetic analysis showed that PRRSV-2 circulating in pig herds in five southern provinces was divided into four lineages,of which 154 strains were identified as lineage 8 strains.After removing a recombinant strain and three suspected strains,the ORF5 sequences from the above five provinces had a strong temporal signal,and the best-fit model was GTR+I+G.Bayesian phylodynamic analysis showed that lineage 8 strains from five provinces had nucleotide evolutionary rates of 2.748×10-3/site/year (95% HPD:2.053×10-3-3.428×10-3),and their most recent common ancestor might have emerged in 2002 (95% HPD:1998-2005).According to SPREAD3 calculations,Guangxi strains spreaded to Guangdong (Rate=0.876),Hunan (Rate=0.892),Jiangxi (Rate=0.883),and Fujian (Rate=0.889),as well as some Fujian strains spreaded to Guangxi (Rate=0.897).【Conclusion】 Since 2005,PRRSV-2 circulating in pig herds in Guangdong,Guangxi,Hunan,Jiangxi and Fujian provinces had rich genetic diversity,of which lineage 8 strains had a high nucleotide substitution rate,and the effective population size had increased significantly from 2006 to 2007 and 2009 to 2013.The common ancestor of lineage 8 strains of Guangdong,Guangxi,Hunan,Jiangxi and Fujian provinces might have emerged in 2002,and continued to spread in the region with Guangxi as a potential origin.

Key words: Porcine reproductive and respiratory syndrome virus (PRRSV); molecular epidemiology; Bayesian phylodynamics; phylogeography

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