| Objective:Using gE-ELISA and gB-ELISA kit evaluation analysis the infection rates of wild PRV of two large-scale farm at Nanping Yanping District. Establish a PCR diagnostic method on the vertical transmission risk analysis of the two pig farms.Method:Detect Porcine pseudorabies antibody of gE and gB in large scale pig farm of Nanping Yanping District from November to December 2014, and evaluation analysis the results, evaluate the wild pseudorabies infection positive rate of two large-scale pig farms. Compare the statistical result and the animal epidemic diseases investigation results in Yanping in 2013.To evaluate the PRV epidemiology of two pig farms in 2014.Establish PCR diagnostic method based on gE gene, and analysis the specificity, sensitivity, repeatability and consistent with national standards of PCR.Use the PCR diagnostic method to detect boar semen and umbilical cord blood witch the gE antibody positive of the two large-scale pig farms and Yanping District.Compared to two pig farms of umbilical cord blood and semen PCR positive detection rate and the average positive rate of 12 pig farms, evaluation the vertical transmission risk pressure of two large-scale pig farms.Results and analysis:Pig farm A with a total sample of 353 sera, pig farm B with a total sample of 267 sera, gE antibody detection results showed that both A and B farm boars were negative to PR wild virus, indicating the boars were not infected by PR wild virus, except that, all other pigs were positive, the total positive rate were:51.08%,58.80% respectively, indicating that the two pig farms are all PR wild virus positive farm. The gE antibody positive rate of sows were 53.87%,46.15% respectively. The positive rate of 30-40 day old pigs were 26.09%,51.16% respectively, count in suspected pigs,the positive rate were:31.89%,51.16%. The positive rate of 60 day old pigs were 45.45%,65.96% respectively, and 120 day old pigs gE antibody positive rates even as high as 90%. Therefore, we can infer that when the pigs transferred from nursery house to fattening house, they were infected by PR wild virus. gB antibody test results showed that:the positive rate of the two farm were 96.87%,96.84% respectively; the gB antibody positive rate of boar all were 100%; the gB antibody positive rate of sows were 93.4%,100% respectively, antibody levels high and the dispersion degree was low, these results may be a comprehensive effect of vaccine infection and wild viruse infection;the gB antibody positive rate of 30～40 day old pigs were 94.20%,97.67% respectively, and the evenness is high, so it can be concluded that in addition to the influence of maternal antibody, two pig farms immunization effects were good, and the antibody level of A farm was higher than that of B farm; the S/N value of gB antibody of 60-120 days old pigs decreased, means the antibody level increased, and in this stage, maternal antibody has almost disappeared, gE antibody did not decreased but increased, so infer the pigs were infected by wild virus when transferred at 60-120 days old, especially at the 120 days old.In 2014, the average gE antibody positive rate of A farm was 51.08%, the average gE antibody positive rate of B farm was 58.80%, compared to swine pseudo rabies virus infection survey results of 20 farms in Yanping District in 2013, the gE antibody positive rate did not decline, and from a clinical survey,A, B two farm no outbreak of disease. This leads to the conclusion that the pigs of two farm were silentinfection, although in 2014, PR has been effectively controlled in A, B two farm, but silentinfection and detoxification phenomenon were more serious. It is necessary to develop an effective immune procedure, strengthen the immune vaccine and improve breeding conditions.In the present study, we builded a specificity, sensitivity, and reproducibility PCR diagnostic method based on the gE gene fragment. Using this method, the detection results of wild virus, vaccine viruse and negative sample were consistent with the national standard. Using this method, we conducted the umbilical cord blood and semen of 12 pig farms and A,B farms in Yanping District. Test results were as follows:12 pig farms with a total 132 samples of umbilical cord blood, the positive rate was 31.82%, the positive rate of A farm was 57.14%, the positive rate of B farm was 60.71%; 12 farms with a total 86 samples of boar semen, the positive rate was 15.12%, the positive rate of A,B farm all were 0.00%. Therefore, we can infer that A, B two pig farms the vertical transmission from the sows to the piglets were in pressure, higher than the average level in 12 pig farms, but though boar semen spread temporarily has no danger. The results of gE and gB antibody testing show that both pigs are invisible infection in addition to the boars, but without clinical symptoms,thus it can be seen the pigs get effective control and production is relatively stable, but from conservation of piggery-fattening pig house, gE antibody increased significantly,at this stage piglet has receded maternal antibody,combined with factors such as environment mutations,pigs easy to be infected by PRV due to stress, In addition, the sow foreign detoxification to make the virus in an internal loop,so the first free piglets and fattening pigs monitoring is the key to stable gE antibody positive.Conclusion:While through vaccination can reduce the PRV spread effectively but most of the pig farms did not eliminate the PRV completely part of the immune pigs still detoxification possibility, even threaten susceptible herd of swine,So both pig farms need to strict immune prevention and control of the sow, as far as possible eliminate positive pigs, lest cause pig breeding production pressure, guarantee the quality of the newborn piglets.Testing the pigs’PRV-gE and PRV-gB antibodies of different farm with ELISA detection method,and to evaluate the result, as the judge whether the pig infected with wild, vaccination is the basis of best results, and analysis to assess the risk of vertical transmission of test pigs combined with PCR diagnostic method,it has the practical significance to guide large-scale pig farms full implementation of pseudo rabies purification. |
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