Epidemiological Investigation And Differential Diagnosis Of Brucella In Dairy Cows

The diagnosis of Brucella depends on clinical symptoms and experimental examinations,and serological examinations are the first choice.These experiments are easy to carry out.In this study,a new detection method,high-sensitivity fluorescent quantitative detection,was used to evaluate its detection rate,sensitivity and specificity.At the same time,the serological method agar diffusion test(NH-GD)and real-time fluorescence quantitative PCR method were used to diagnose and identify the wild strain of Brucella bovis and the A19 vaccine strain.Prevention and control mechanisms of Rheumatoid bacteria.An epidemiological survey was conducted on 5 cattle farms in a northwest region to understand the local situation of brucellosis infection.1286 serum samples from cattle suspected to contain Brucella were collected and passed serological tests,national standard tiger red plate agglutination test(RBT),test tube agglutination test(SAT),OIE standard fluorescence polarization test(FPA)and high-sensitivity fluorescence quantification 50 healthy cows were screened from the cattle farm in the area to be inoculated with A19 vaccine and monitored,and the national standard and OIE standard detection methods and agar diffusion test(NH-GD)were used for detection;among the 4 methods,the For the cattle corresponding to the sera with positive test results,15 milk samples were collected for the isolation and identification of Brucella,and real-time fluorescence quantitative PCR was used to diagnose and identify the samples.Through epidemiological investigation,the positive rate of brucellosis in this area is relatively high,especially in pasture five with serious brucellosis infection,and the positive rate of random inspection reaches 60%;Simple and rapid on-site measurement.Compared with the SAT test results,the coincidence rate of the high-sensitivity fluorescence and the SAT test results is the highest 90.04%,the highest sensitivity is 93.62%,and the specificity is the lowest 87.29% compared with the RBT test results.In FPA,the high-sensitivity fluorescence specificity was the highest at 88.55%;the 12 isolates were biochemically identified,and the 12 isolates were all Brucella bovis type III.After verification,it was found that it can identify the vaccine strain A19 and the wild strain.In the SAT test and the NH-GD test,the highest coincidence rate was 93.86%,and the specificity was also the highest 92.14%;Brucella positive standard was constructed,make a standard curve,the correlation coefficient is R2=0.9989,real-time fluorescence quantitative PCR method can further identify the infection of Brucella bovis wild strain infection and A19 vaccine strain infection.Therefore,it is necessary to combine other detection methods to improve the identification of brucellosis,which can more effectively prevent this type of disease.Through a large number of tests,the high-sensitivity fluorescence test has the characteristics of high sensitivity,good specificity and low cost of use.The detection of brucellosis provides an easier way to better reduce losses in animal husbandry.