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Porcine reproductive and respiratory syndrome (Porcine reproductive and respiratory syndrome, PRRS) is a highly contagious disease, a pig to infect pigs of different age, breed and sex, but most pregnant sows and piglets less than 1 month old susceptible. was spreading in the country. Beginning in May 2006, the pigs in southern China to the pigs body temperature increased, purple skin and shortness of breath were the main symptoms, pathological change of diffuse hemorrhagic interstitial pneumonia, lymph nodes and internal organs organs varying degrees of bleeding of the main features of the disease. Disease outbreaks and epidemic has brought huge economic losses to the pig industry in China. At first, its etiology is unknown, it is called \Highly pathogenicporcine reproductive and respiratory syndrome virus, HP-PRRSV). In this study, several areas in Guangdong Province multiple farms pathological samples detected PRRSV strains isolated and identified the different parts of the pig farm, so as to explore the prevalence of PRRSV in different regions of Guangdong Province, which PRRSV mutation (deletion) strain , and PRRSV classic (non-missing) the existence and prevalence of strains; and isolated strains Nsp2, ORF3 the ORF5 gene cloning and sequence analysis to study the molecular genetic relationship of these strains; virulent PRRSV variability of Guangdong Province strain (GDYF) gene sequence analysis, to study the relationship between the Molecular Genetics of the the PRRSV-Pop virulence domestic PRRSV strains. The main contents and results of this study are as follows: 1. Of 161 Hair pigs collected from Guangdong Province of Yunfu, Enping, four, Guangzhou, Foshan, Shenzhen and other 12 regional farms serum, lung treatment, spleen and The lymph nodes of mixing processing of 278 samples by RT-PCR for PRRSV detected simultaneously received Marc-145 cells, respectively, after the processing of these samples virus isolated. The results show that: the Institute survey of 161 hair pigs infected with PRRSV 88, the positive rate was 54.7%; 65 samples isolated on Marc-145 cells to PRRSV RT-PCR method to determine the separation of PRRSV serious Guangdong Province Americas PRRSV infection; American type, which the serum samples of the detection rate and the highest separation rate, followed by lung, spleen and lymph nodes are relatively poor. In addition, in Guangzhou and the same area at the same time isolated classic PRRSV and mutation type PRRSV that Guangdong Province PRRSV the PRRSV and mutation (deletion) in the classic (non-missing) PRRSV two types exist, which mainly mutant popular mainly. (2) on 17 isolated Guangdong Province PRRSV epidemic strains Nsp2, ORF5 and ORF3 gene sequence analysis. The results show that: the isolates in addition to the deletion GDGZ3 and GDSH1 strains, and the remaining 15 the strain Nsp2 gene occurred discontinuous missing 30 amino acids, the missing position 482 and 533 to 561 amino acids, with HP the main feature pertinence of-PRRSV isolates JXA1 the; the the the 15 PRRSV mutants with HP-PRRSV strains JXA1, GD, HUN4, HUB1 HEB1 the laboratory isolated Henan-1 ORF3 the ORF5 gene nucleotide sequence deduced amino acid homology with the standard strains ATCCVR-2332 strain of vaccine strains RespPRRSMLV low homology; the GDGZ3 and GDSH1 strains with higher RespPRRSMLV ATCCVR2332 nucleotide sequence and deduced amino acid homology lower HP-PRRSV strains JXA1 strain, etc. homology; established genetic basis the Nsp2 gene phylogenetic tree analysis can be found the 15 PRRSV mutant was close, and the HP-PRRSV strains JXA1 GD, HUN4, HUB1, HEB1 and Henan-1 strains kinship closer PRRSV epidemic strains of Yunfu, Guangdong Province, Shenzhen and other regions may be evolved by the same strain; GDZC3 ATCCVR2332, RespPRRSMLV strains of kinship than , this strain may be evolution of RespPRRSMLV strains from GDSH1 with domestic vaccine strain CH-1a strain homology high, a closer relationship, suggesting that this strain CH-1a strain evolved. 3 sub-RT-PCR amplification the Guangdong Province PRRSV epidemic strains GDYF, genome, with reference to the VR-2332 sequence, based on the overlapping area between the fragments, the sequence of the amplified fragment were stitching get GDYF strain complete genome-wide , and be analyzed by DNA Star software. The results show that: the GDYF strain Nsp2 region of 30 amino acids missing discontinuous, the location of the missing 482 amino acids and 533 to 561 amino acids, compared with HB-1 (sh) / 2002, of the first 481 amino acids of Nsp2 by D mutation the the GDYF strain with the HP-PRRSV strains JXA1, GD, HUB1 HUN4, HEB1, Henan-1 and HB-1 (sh) / 2002 strains of each reading frame amino acid sequence homology of 96.8% to 99.2 E; %; VR2332, RespPRRS MLV and CH-1a strain Nsp2 deduced amino acid homology of 75.8% to 87.4%. Phylogenetic tree shows that the genetic system, in contrast with 2006 HP-PRRSV strains GDYF the strain JXA1 genetic relationship closer; 2006 separation the PRRSV strains contrast, GDYF, strains and HB-1 (sh) / 2002 strains closer relationship, a study has proved JXA1 strain is evolved by the HB-1 (sh) / 2002, which can to speculate GDYF with JXA1 strains may evolve from the same strain HB-1 (sh) / 2002 from. GDYF with HP-PRRSV strains JXA1 reference strains contrast ORF1a, ORF1b, ORF5 gene deduced amino acid point mutations.
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