| At present, the epidemic disease is one of the important factors affecting the pig industry in Jiangxi, and there are many problems such as the species of the epidemic, the variation of pathogenic and the mixed infection of the pathogen etc. As the growth of pigs, nursery pigs are the most prone to disease in the large-scale pig farm pigs(especially pathogen infection)for the level of maternal antibody gradually decline and weaning factors such as stress,vaccine immune protection that is not fully formed. In order to get the pathogen infection and variation of pig breeding in jiangxi area, this thesis collectes information about dead nursery pigs from part of pig farms in jiangxi provice, adopts molecular biology method to analyze four kinds of virus infections,classical swine fever virus(CSFV), porcine reproductive and respiratory syndrome virus(PRRSV), porcine circovirus type 2(PCV2)and porcine pseudo rabies virus(PRV). It also randomly researchs some strains in sequencing and respectively understands the variation of pathogen, offering some references to prevent main disease for pig farms in Jiangxi province.1. Investigation of conservation swine’s pathogen infection in jiangxi area January 2014 to December 2014, we collected 546 pathologic materials in different scale pig field from Nanchang, Yichun, Ji’an and Ganzhou, Fuzhou, Jiujiang and Shangrao region in jiangxi province. We investigated each pathologic material respectively from the PCR/RT- PCR detection of the porcine reproductive and respiratory syndrome virus(PRRSV), swine fever virus(CSFV), porcine circovirus type 2(PCV2) and pig pseudo rabies virus(PRV) four diseases virus. The results as follows: the positive number of PRRSV is 375, which accounts for 68.6% of the total sample; the CSFV is 204, which accounts for 37.3%; the PCV2 is 275, which accounts for 50.3%; the PRV is 70, which accounts for 12.8%.2. The analysis of four types of pathogen infectionFrom the perspective of the type of infection, in 546 samples, there are 203 copies of single infection, accounting for 37.1% of the total number of samples. There are 308 copies of double mixed infection, it accounts for 56.3%. Triple infection 30, accounting for5.4%.Four heavy infection 5, accounting for 0.9%. The investigation results show that the multiple infection of conservation swine’s pathogen is generalization.PRRSV, CSFV,PCV2 and PRV double mixed infection is high to 62.9%.In double infection, the infection rate of mixed “PRRSV+ PCV2”and“PRRSV + CSFV”is higher, which accounts for 45.1%and 31.8% respectively of double mixed infection.4. The analysis of PRRSV, CSFV, PCV2 and PRV( 1) The homology of Nucleotide and amino acid between 12 strains of swine fever epidemic is in 96.5%-100% and 92.4%-100%; the homology of nucleotide of Jiangxi epidemic strains and the virulent Shimen strain is in 82.6%-83.3%. CSFV can be divided into two groups, the 1 group and 2 group, according to the analysis of genetic evolutionary tree, the 13 sequenced strains of Jiangxi belonged to the 2 group of 2.1 b subgroup.(2)The homology of nucleotide and amino acid between 15 strains of PRRSV strains ORF5 gene is in 93.7%- 99.7% and 92.1%- 100%. And that in American strain(VR2332)is in 84.2%- 89.2% and 84.2%- 89.1%, in European strain is in 79.7%- 87.1% and 82.1%- 86.9%. The 15 type PRRSV strains are in America strain.( 3) The homology of nucleotide and amino acid of 11 strains of PCV2 is in94.2%-99.7%and 64.2%-93.2%.We can draw a conclusion from the analysis of the genetic evolutionary tree: 9strains belong to PCV2 b and 2 strains belong to PCV2 a.(4)The homology of nucleotide and amino acid of 9 strains of PRV gB virus is up to94.7%-100% and 99.5%-99.9%. Compared with BARTHA-2011, the nucleotide homology is 97.8%-97.9%, and the homology is 98.0%-98.2% compared with the BARTHA strain.By analyzing phylogenetic, 9 strains epidemic strains belong to a large group with close relationship. |
PDF Full Text Request