| Brucellosis is a chronic zoonotic bacterial infectious disease caused by Brucella.The disease is a global epidemic,of great public health significance and inflicts huge losses on the world economy.By comparing the specificity,sensitivity and coincidence rate of six laboratory detection methods,RBT,SAT,i-ELISA,c-ELISA,FPA and fluorescent microspheres colloidal-gold detection kit,a comprehensive detection model suitable for different environments was selected.In order to understand the epidemic situation of sheep brucellosis in Ningxia,9330 serum samples and 2003 environmental swabs from various cities in Ningxia were investigated by RBT,c-ELISA and RT-PCR,and the risk factors involved in the questionnaire were analyzed by logistics regression model.In order to explore the law of the rise and fall of antibodies of sheep immunized with Brucella S2 vaccine and the protective strength of S2 vaccine,whole blood and nose swabs were collected from sheep at 7d,14d,28d,60d,90d,120d,150d and 180d after immunization with S2 vaccine,and environmental swabs were collected in the pens.The collected samples were detected by RBT,SAT,c-ELISA,i-ELISA,FPA and RT-PCR,and the comparative study was conducted.The results are as follows:1.Comparison of six detection methods for brucellosis.The results showed that the sensitivity of i-ELISA,c-ELISA and fluorescent microsphere colloidal gold was 96.67%.The sensitivity of SAT and fluorescence polarization was 93.33%.The sensitivity of RBT was 90.00%.The specificity of the six methods was 100%.The coincidence rate was above 95%.2.Epidemiological investigation and risk factors analysis of sheep brucellosis in Ningxia.Serological test results showed that the individual positive rate was 8.63%and the population positive rate was 41.44%.The positive rate of immunized sheep was 5.50%and that of unimmunized sheep was 9.26%.The positive rate was 54.26%in large-scale farms,32.67%in free-range households,28.57%in slaughterhouses and 55.56%in trading markets.Etiological detection results showed that the positive rate was 36.70%in large-scale farms,9.55%in free-range households,37.50%in slaughterhouses and 40.00%in trading markets.The analysis results of risk factors showed that the main risk factors of brucellosis in sheep in Ningxia were "purchasing or exchanging new animals","unsterilized conveyance of feed" and "abortion or infertility of ewes in the past year".3.S2 vaccine antibody growth and decline law on protective power.Serological results showed that the antibody positive rate of animals in the three groups reached the peak at 14 to 28 days after immunization,and remained above 20%at 180 days after immunization.RT-PCR results showed that the antigen positive rate of group A nasal swabs was 40.91%at 7 and 14 days after immunization.The antigen turned negative at 28 days after immunization and turned positive at 150 days after immunization.Group B had the highest antigen positive rate(72.73%)at 28 days after immunization;60 days after immunization,the antigen turned negative;150 days after immunization,the antigen turned positive;Group C had the antigen positive rate at about 10%. |
