Molecular Epidemiology Survey, Isolation And Identification Of The Porcine Reproductive And Respiratory Syndrome Virus In Henan Province From2012to2013

Porcine respiratory and reproductive syndrome (PRRS) is recognized asa serious swine disease and is characterized with either reproductive failure stillbirthand mummified in pregnant sows, or respiratory tract distress particularly in suckingpigs. The etiological agent of PRRS is porcine reproductive and respiratory syndromevirus (PRRSV) has caused enoumous economic losses in China since it first emergedin1996, especially HP-PRRSV emerged in2006. The aim of this study is tounderstand the prevalence station and provide a reference in PRRS prevention andcontrol of Henan region through molecular epidemiology, analysis of recombinantbetween two strains of the new variant and isolation of Henan strains.1. Molecular Epidemiology of Porcine Reproductive and Respiratory Syndrome VirusPrevailing in Henan Province from2012to2013Of the54clinical samples collected from2012to2013,17(31.5%) were positivefor PRRSV; The result of phylogenetic analysis of ORF5and NSP2genes indicatethat the highly pathogenicPRRSV (HP-PRRSV) has become the dominant strain,10samples are positive forHP-PRRSV,2samples are positive for classic PRRSV, but another5samples areneither HP-PRRSV nor classic PRRSV, they are similar with USA strain NADC30which have delete393nt in NSP2gene. this study indicate that the highly pathogenicPRRSV (HP-PRRSV) has become the dominant strain and emerged PRRSV newvariant, it make the types of PRRSV more diverse in Henan province and even inChina, it is necessary to pay more attention on the monitor of PRRSV.2. Complete genome analysis of Henan PRRSV new variant strain HENAN-XINXand HENAN-HEBTo further investigate the genetic variation of Henan PRRSV new variant strainHENAN-XINX and HENAN-HEB, ten pairs of primers were synthesized andRT-PCR method was used for amplification of the complete genome of two strainsreference the most closly related strains published in Genbank. A phylogenetic tree based on the entire genome sequence of representative PRRSV strains showed thattwo strains were more closely related to USA strain NADC30. Recombinationanalysis showed that the HENAN-XINX was likely to be the result of S1straincombine with NADC30strain. This study further demonstrated that the new variantstrain not only emerged in China but also acquired the ability of adapt living conditionof PRRSV fastly, we should pay more attention on them.3. Isolation and identification of PRRSV Henan strainsThree porcine reproductive and respiratory syndrome virus were isolated from17positive specimens through continuous passage culture on Marc-145, The isolateswere identified by RT-PCR and IFA test. This study provided a reliable experimentmaterial on the study of PRRSV pathogenic and pathogenesis and enrichedepidemiological database of PRRSV.