| Poreine reproductive and respiratory syndrom (PRRS) commonly known as the blue ear disease, is caused by porcine reproductive and respiratory syndrome virus (PRRSV) a high mortality caused by infectious disease in piglets respiratory symptoms and pregnancy sow reproduction disorder characterized by. Nineteen eighties, the disease was first reported in the United States, quickly after the widely circulated around the world, brings a huge threat to the global pig industry. Data show that, fourth days after PRRSV infection in boar semen can be detected from the PRRSV virus particles, while the boars appearance does not show any clinical symptoms. The virus can transmit the virus to the boar sows through semen, and sow pregnancy through vertical transmission of the virus to the fetus virus through the placenta, infected piglets can spread virus, pollution of the environment, eventually infect otherwise healthy pigs.According to the GeneBank of porcine reproductive and respiratory syndrome (PRRSV) NSP2, ORF5gene sequences were designed can distinguish classical strain PRRSV NSP2-F, NSP2-R and ORF5gene was amplified by ORF5-F, ORF5-R two pairs of specific primers, In many regions of Sichuan Province from67boar semen were detected by RT-PCR, and collected the67boar serum ELISA antibody detection, in order to provide reference data for prevention and control of Sichuan Province of porcine reproductive and respiratory syndrome. The main results are as follows:1. A total of7PRRSV positive detection of semen from the semen, the detection rate was8.46%, of which5is the highly pathogenic PRRSV strain of highly pathogenic PRRSV strain, the detection rate of all samples detected71.4%, the rest of the classic PRRSV strains, these strains were named as MS-1, MS-2, QL-1, SN-1, SN-2, PJ-1, PJ-2. From the experimental data can be obtained, since the2006outbreak of highly pathogenic PRRS, PRRSV deletion mutant spread quickly, and soon replaced the leading position of the classic PRRSV strain, So far, will be gradually eliminated PRRSV classical strains.2. In semen collection also collected boar serum, using IDEXX HerdChek of porcine reproductive and respiratory syndrome virus antibody detection kit for PRRSV antibody level in serum was detected in all, Uneven in the event of suspected blue ear disease symptoms in Meishan, Qionglai, Suining, Leshan, Pujiang several farms boar serum PRRSV antibody levels, high and low, The s/p value of the coefficient of variation were achieved respectively59%,81.2%,67.6%,66.3%,60.5%,53.46%, and the appearance of normal Mianyang, Ya’an pig boar body antibody titers are consistent, s/p value and coefficient of variation were22.1%,17.5%, Validation of the PCR results from the antibody level.3. Using DNAstar software MegAlin, comparing the results of this study MS-1, MS-2, QL-1, SN-1, PJ-15copies of the highly pathogenic PRRSV strain of semen samples of amplified ORF gene sequence and5domestic representative strain CH-la, BJ-4, JXA1, HEB1, HUB2ORF5gene, the results show, obtained in the study of5highly pathogenic PRRSV strain ORF5nucleotide homology in88.1%(MS-1and QL-1) and-99.3%(SN-1and MS-2), comparing the results with the domestic representative strains, and BJ-4homology is low, at88.4%(SN-1)-99.2%(QL-1), and the homology of HUB2, in88.4%(QL-1)-99.7%(MS-2); and the foreign representative strains of European standard strain LV, American standard strain VR-2332, the results of vaccine strain MLV, the amplified ORF5encoding gene sequence homology with American VR-2332isolates have high homology (respectively MS-1:88.7%, MS-2:89.4%, PJ-1:89.5%, QL-1:99.3%, SN-1:89.2%), and with the European representative strain LV of low homology (MS-1:63.4%, MS-2:63.2%, PJ-1:63.8%, QL-1:63.4%, SN-1:63.4%), From the establishment of genetic evolutionary tree, we can know from the evolutionary tree, the amplified MS-1, MS-2, QL-1, SN-1, PJ-15copies of the highly pathogenic PRRSV strain of semen samples of amino acid sequence, Except for QL-1, all in the same small branches, and with the HEB1, JXA1showed the highest homology, the closest relationship, strain VR2332, MLV, CH-la, BJ-4and other classical strains sequence relationship and separation and before2006was far.4. Amino acid sequence of the obtained MS-1, MS-2, QL-1, SN-1, PJ-15copies of the highly pathogenic PRRSV strain was amplified in5semen samples of ORF gene sequencing analysis, results showed that, samples GP5protein amino acid mutation, among them, the most significant regional variation occurred mainly in the amino acid residues in the1-25position of signal peptide and29-39location, in this study, the PRRSV in5samples of GP5amino acid residues thirteenth were R13;151st were R151, the Research Institute of Sichuan area shows the5PRRSV strains were virulent features, not from the vaccine strain. SN-1, QL-1Q196→L196mutation, mutation consistent with JXA1, MS-2Q196, R196, MS-1, PJ-1and no mutation. The T cell epitopes of the first epitope located in the GP5protein of117-131amino acid residues, all this study obtained5Sichuan area semen samples were no mutation. |
