Epidemiological Investigation Of Porcine Reproductive And Respiratory Syndrome In Xinyang

The porcine reproductive and respiratory syndrome(PRRS) is one of the causative diseases which has risen humorous economic losse on swine industry. Its pathogeny is the porcine reproductive and respiratory virus(PRRSV). The disease is characterized by reproductive troubles such as abortions farrowing or weak piglets, preweaning piglets pneumonia mortality and mortality in sows. To investigate the prevalence station, its distribution, occurrence,spread approach in Xinyang, to further research its variation laws. this thesis provide an consult thereunder to effectively establish a prevention program on this disease.One pair of primers were designed according to M gene sequences of PRRSV published in GenBank. a 420 bp was amplified to establish a RT-PCR assay, were used to detect PRRSV, CSFV, PRV,PCV and negative control. The results showed that except for PRRSV,other detect results are negative; RNA was extracted from 250μL PRRSV cell virus, be diluted 10-1-10-8, a visible objective strip can be amplified still; The same result can be gained in numeral repeated tests.This indicated that the established nested PCR assay has the virtues of stronger speciation, higher sensitivity and well stability. The suspected samples were tested useing this methods in all 10 regions. The results showed that the positive rate is 55.4%(265/478).Indirect enzyme-linked immunosorbent assay(ELISA) was also used to monitor the antibody against PRRSV of 1329 serum samples from non-vaccinated herds without clinical signs of 86 farms in Xinyang. The results showed that The average positive rate was 49.5%,the highest positive rate was 65.9% in Pingqiao,the lowest positive rate was 27.8% in Gushi. The highest infection rate was 56.3% of Landrace , the lowest infection rate was 30% of Huainan pig. The highest infection rate were the neonatal pigs. The positive rate in the regions with many and small-scale pig farms was relative high.In summary, in this experiment, a RT-PCR detection method was established and clinicaled application. Indirect enzyme-linked immunosorbent assay(ELISA) was also used to monitor the antibody from non-vaccinated herds. This study provided an consult thereunder to effectively establish a prevention program on laws, paved the way of the healthy development of swine industry in this in area.