Validity of SPA in quantal assay of antibodies to BVD virus in field serum samples

ABSTRACT

76 bovine serum samples were collected from different farms and tested for the presence of antibodies to BVD virus. For this purpose, the SPA-agllutination test has been introduced as a new approach in comparison with the serum neutralization test [SNT] and the immunodiffusion [ID] technique. Therefore, the samples have been categorized in four groups according to their titers in the SNI 1st group included positive sera with high antibody titer [32 to 64]; 2nd group included positive sera with medium antibody titer [8 to 16]; 3rd group contained cytotoxic samples and the 4th group comprised all negative samples. The obtained data could prove that the SPA test as a binding assay is relatively more sensitive than the SNT in detecting antibodies to BBVD virus giving end titers ranged from 16 to 128. The SPA test could also detect anti-BVD antibodies in cytotoxic serum samples. Although the ID test is a simple technique for detection of antibodies yet it was of relative lower sensitivity than the SNT and SPA agglutination tests, and showed itself in this work non-suitable for screening of antibodies to BVD virus