| Porcine reproductive and respiratory syndrome is caused by porcine reproductive and respiratory syndrome virus (PRRSV). At present, the disease widely spread in the world, cause swine reproductive and respiratory syndrome with low immunity, higher morbidity and mortality and huge economic losses to the pig industry and bring hidden danger in the meat product safety and environmental safety. In order to timely effectively understand regionality infection and prevalence of PRRS disease. Antigen antibody detection and RT-PCR ELISA has been most frequently used in production practice and laboratory. Genetic variation analysis of highly pathogenic PRRSV at molecular level can provides a theoretical basis for the prevention and control of the disease in the next step.Highly pathogenic PRRS antibody of 1404 pig serums, from 9 areas of Mian yang in 2013 and 2014, were detected by the ELISA method. The result showed the antibody qualified rate of samples was 81.3%, the variation coefficient of sam ples was 20.9%, the overall level was ideal and meet the basic requirements of th e Ministry of Agriculture (more than 70%). Compared in different sample groups, the antibody qualified rate ranged from high to low was farms (91.8%)> farmer s (81.7%)> slaughterhouse (70.5%), and the coefficient of variation ranged from 1 ow to high was farms (14.8%)< farmers (18%)< slaughterhouse (30%). Through the Mianyang area method for the detection of RT-PCR was detected in this exp eriment part of the suspected swine were collected in 78 copies. Results the avera ge positive rate from high to low is the highly pathogenic PRRSV (35.90%)>PRR SV (17.95%)>HP-PRRSV+PRRSV (11.65%). And part of the region were detected in the samples of slaughter 282, the positive rate of PRRSV was 2.84%, the pos itive rate of high pathogenic PRRSV 11.70%, no HP-PRRSV+PRRSV mixed infec tion. HP-PRRSV is still in the area of blue ear pig disease infection rate of strain type. After the diseased antigen detection after screened 69 strains, and Nsp2, th e ORF5 gene was amplified by RT-PCR analysis, purification, sequencing. The ho mology was 90.2%～100% nucleotide sequences of 49 Nsp2 genes, deduced amin o acid homology is 73.7%～100%; With the LV nucleotide sequence homology w as 49.7%-50%, deduced amino acid homology is 31.1%～37.2%; MLV and VR-2332, the homology of nucleotide was 79.2%～82.6%, deduced amino acid homol ogy is 60.8%～75%; Before 2006, with domestic BJ-4 HB-1 (SH), the homology was 79%～95.1% HN1 virus nucleotide, deduced amino acid homology is 70. 9%～92.6%;With the separation of China after 2006 and the strains JXA1, SYO608 nucleotide sequence homology was 93.1%-98.6%. The deduced amino acid hom ology is 83%～98.5%. Between 20 ORF5 and the homology of nucleotide sequenc e was 91.9%～100%, the similarity of deduced amino acid is 88%～100%; The ho mology with LV from 62.6% to 65.8%, the similarity of deduced amino acid is 5 6.6%～59.2%; the homology with VR-2332 from 88.2% to 90.2%, the similarity o f deduced amino acid is 86.5%～89%; and in 2006 before the HN1 strain the ho mology was 87.1%～90.2%, the similarity of amino acid is 84.5%～90%; and in 2006 and after the strains JXA1, SXHZ01 homology is 95.2%～99.2%, the simil arity of amino acids was 89%～99%. N-glycosylation site prediction of GP5 fro m 4 to 5, the decoy epitope A mutations, The neutralizing epitope of B quasispec ies evolution is more conservative, the wild strain (S137); The Mianyang area HP-PRRSV mutation and other domestic strains are different, AA found new mutatio ns and deletion region,homology and phylogenetic tree showed that belong to Am erican genotype and JXA1 in a subgroup, More recent discovery and after 2006 a nd the phylogenetic relationship. |
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