Detective Methods Of The Role Swine Viruses And Detection Of Four Virus And Its Antibodies In Pig Population Of Shaanxi Province In 2015

At present, classical swine fever(CSF), porcine reproductive and respiratory syndrome(PRRS), pseudorabies(PR), porcine circovirus disease(PCVD) are all the important viral diseases that seriously harm to Chinese pig breeding industry. Pathogen detection is the most direct basis for disease diagnosis, and the common methods include virus isolation and identification, molecular biology and serology tests(immunoperoxidase monolayer assay, indirect immunofluorescence test, neutralization test and ELISA), etc. Antibody level is the most commonly used indicator to evaluate immune status of animals and an important basis for making immunization programs as well. This study established multiplex RT-PCR detection method of classical swine fever virus(CSFV), porcine reproductive and respiratory syndrome virus(PRRSV), multiplex PCR detection method of pseudorabies virus(PRV), porcine parvovirus(PPV) and porcine circovirus type 2(PCV2), which providing a useful technique for the rapid detection of these viruses. In addition, the immunoperoxidase monolayer assay(IPMA) method for detecting CSFV and PCV2 was established, it provides a reference to quantitatively detect cells of non-cytopathic(nCPE) virus in vitro. In 2015, 696 swime serums which collected from large-scale pig farms, slaughter houses and Household raising farmers of 22 regions in Shaanxi Province were tested for CSFV, PRRSV, PRV and PCV2 and their antibody levels. The results are as follows:1. Multiplex RT-PCR(PCR) method of detecting 5 swine viruses was established(1) A double RT-PCR method to detect CSFV and PRRSV was established. PCR conditions for the optimal annealing temperature was 60 ℃, primer final concentration was 0.4 μmol / L; CSFV amplified fragment length was 438 bp, PRRSV’s was 535 bp; nucleic acid lowest detectable amount of CSFV was 7.5 pg / μL, PRRSV was 14.2 pg / μL.(2) A triple PCR method to detect PCV2, PRV and PPV was established. PCR conditions for the optimal annealing temperature was 56 ℃, PCV2 and PRV primer final concentration was 0.2 μmol / L, PRV was 0.3 μmol / L; PCV2 amplified fragment length was 880 bp, PRV was 213 bp, PPV was 295 bp; minimum detection of PCV2 DNA amount was 6.9 pg / μL, PRV was 9.2 pg / μL, PPV was 8.6 pg / μL.2. IPMA method to detect CSFV and PCV2 was established respectively. The diluted concentration of CSFV, PCV2 first antibody(swine fever positive serum, rabbit anti-PCV2 positive serum) both were 1: 300, and the HRP-SPA was of good sensitivity and specificity with the concentration 1: 2000.3. The testing results of 696 pig serum samples in 2015 which collected from 22 regions in Shaanxi Province showed that, CSFV antibody positive rate was 81%, PRRSV was 70%, PCV2 was 83%, PRV-gI was 21%, and PRV-gB was 38%. Further more,CSFV nucleic acid positive rate was 9%, PRRSV was 14%, PCV2 was 23%, and PRV was 20%.In 2015, the infection of these four viruses was existing in swinery of Shaanxi, CSFV, PRRSV and PRV-gB antibody levels have yet to be improved; the infection rates of the four virus were higher in individual pig farms, and there existed the risk of epidemic diseases occurring. Therefore, enough attention should be paid, prevention and control measures should be took in time.