title: Preliminary Study on Prevalence, Risk Factor and Genetic Homogeneity of Porcine Reproductive and Respiratory Syndrome Virus in Registered Pig Farms in Heilongjiang, China.
abstract: While porcine reproductive and respiratory syndrome (PRRS) causes great economic losses in southern and central China, systematic studies on the epidemiology of PRRS virus (PRRSV) in Heilongjiang Province had not been performed. Therefore, we conducted a preliminary study to estimate the prevalence and risk factors associated with PRRSV infection, as well as characterize the PRRSV in registered pig farms in Heilongjiang Province, China in 2011. A total of 1237 blood samples were collected from 72 farms and tested by reverse transcription polymerase chain reaction (RT-PCR) for PRRSV. Risk factors associated to PRRSV infection were analysed using logistic regression models. Genes of non-structural protein-2 (Nsp2) and glycoprotein 5 (GP5) from 22 isolates were sequenced for phylogenetic analysis. The results showed that the herd apparent prevalence was 9.7% (95% CI: 6.3, 13.1) in Heilongjiang Province. An increased risk of PRRSV infection on farms was associated with unrestricted movement of external people (OR = 14.1, 95% CI: 1.68, 119.07), close proximity (<1 km) to the nearest house, road or neighbouring farm (OR = 16.2, 95% CI: 1.52, 171.80), and selling farm products at both local and provincial markets (OR = 20.6, 95% CI: 2.02, 210.56). Phylogenetic analysis based on partial amino acid sequences of GP5 and Nsp2 showed that all the 22 PRRSV isolates in Heilongjiang are closely related to the highly pathogenic PRRSV strain JXA1 and belong to the Genotype 2 (American genotype). The prevalence, determination of risk factors and phylogenetic characterization will provide information for future epidemiological studies and a reference for developing surveillance and control strategies in this region.
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: H
authors.initials: H
authors.lastname: Wen
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: W
authors.initials: W
authors.lastname: Sun
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: N
authors.initials: N
authors.lastname: Shen
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: C
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Heilongjiang Institute of Animal Health Inspection, Harbin, China.
authors.forename: G
authors.initials: G
authors.lastname: Sun
authors.affiliation: International Centre of Research in Agronomy for Development, Montpellier, France.
authors.forename: F
authors.initials: F
authors.lastname: Goutard
authors.affiliation: Animal Infectious Disease Diagnostic Center and National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: X
authors.initials: X
authors.lastname: Cai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002681:China / Q000453:epidemiology; D000072480:Farms; D005838:Genotype; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology* / Q000209:etiology / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000302:isolation & purification*; D015995:Prevalence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D011795:Surveys and Questionnaires; D034421:Sus scrofa; D013552:Swine / Q000821:virology*
keywords: China; Heilongjiang Province; Porcine Reproductive and Respiratory Syndrome Virus; molecular evolution; prevalence; risk factor