ABSTRACT
Brucellosis is highly infectious zoonotic disease that causes huge economic losses to livestock farmers by affecting the reproductive potential of animals causing last trimester abortions and infertility. In the present study evaluation of different serological tests to diagnose the seroprevalence of brucellosis in bovines with history of abortion using various serological tests [Rose Bengal Plate Test (RBPT), modified rose bengal plate test (mRBPT), microtitre plate agglutination test (MAT) and indirect enzyme linked immunosorbent assay (i-ELISA)] was carried out. A total of 134 blood samples of cattle and buffalo with history of abortion were collected from organized and unorganized farms. Seroprevalence by mRBPT, RBPT, MAT and i-ELISA was 75.37%, 67.91%, 72.38% and 72.38%, respectively. In organized farms, prevalence of 78.12%, 81.25%, 78.12% and 81.25% while in unorganized farms prevalence of 64.70%, 73.52%, 70.58% and 69.60% was reported by RBPT, mRBPT, MAT and i-ELISA, respectively. The sensitivity and specificity of serological tests by keeping i-ELISA as gold standard were also calculated and the results revealed that sensitivities of RBPT, mRBPT and MAT were 91.75%, 97.94% and 96.91%, respectively, whereas specificities were 94.59%, 83.78% and 91.89%, respectively.
ABSTRACT
Agglutination is the clumping of antigenic particles by antibodies. Several diagnostic kits for infectious diseases of animals and humans, based on slide agglutination/plate agglutination tests like the Rose Bengal Plate Test (RBPT) for diagnosis of brucellosis are used worldwide. False negative and false positive results are commonly encountered in these conventional agglutination tests. Simple, cost effective modifications can help in circumventing these problems. The novel Superagglutination Test reported here is a modified slide / plate agglutination test. False negative results due to smaller clumps formed by low titer of antibodies in serum are minimized by the addition of biotinylated antiglobulin followed by Avidin which forms easily detectable larger clumps. Similarly, prior staining of serum antibodies with a dye helps in differentiating a specific agglutinate formed by both antigen and antibody, from a non-specific aggregate of antigen alone that leads to false positive results. Superagglutination is more sensitive than the current agglutination tests and agglutination based diagnostic kits. The modification steps are easy to perform and give a more accurate diagnosis without much increase in the cost of the test. The economic losses to livestock industry caused by the spread of infectious diseases like brucellosis due to false negative diagnosis and culling/slaughtering of productive animals due to false positive diagnosis can be avoided by employing the new test.