Evaluation of a recombinant MSP5 based dot-elisa for serodiagnosis of Anaplasma marginale infection in bovines

The study was conducted to develop a dot-ELISA for the serodiagnosis of Anaplasma marginale infection in cattle using recombinant A. marginale major surface protein (rMSP5). The dot-ELISA was optimized with 250 ng of antigen/dot, 1:100 dilution of serum and 1:5000 dilution of secondary antibody to differentiate the positive and negative samples. A total of 74 serum samples, collected from the cattle suspected for bovine anaplasmosis, were used to determine the diagnostic potential of dot-ELISA. Recombinant MSP5 based indirect ELISA was taken as the reference test. The diagnostic sensitivity and specificity of the Dot-ELISA was 96.15% and 81.81%, respectively. The positive predictive value (PPV) of Dot-ELISA was 92.59%, negative predictive value (NPV) was 90.0% and accuracy of the test was 91.89%. The Dot-ELISA showed substantial agreement (k value-0.8) with indirect ELISA. The dot-ELISA standardized in the present study is economical, user-friendly and valuable for serodiagnosis of clinical and subclinical bovine anaplasmosis.