Comparison of indirect fluorescent antibody test (IFAT) and slide enzyme linked immunosorbent assay (SELISA) for diagnosis of Babesia bigemina infection in bovines

An indirect fluorescent antibody test (IFAT) and slide enzyme linked immunosorbent assay (SELISA) were standardized for the detection of antibodies specific to Babesia bigemina in experimentally infected bovine calves and subsequently used for the screening of naturally infected bovine and bubaline sera. In experimentally infected calves positive reactivity was detected in sera at the earliest on day 7 by both the tests. Serological studies for detection of B. bigemina specific antibodies in 180 cow and 120 buffalo serum samples procured from endemic zones of Uttar Pradesh and Punjab revealed 56.11% and 23.33% seropositivity, respectively, both by SELISA and IFAT. Variation in the reactivity pattern between these tests was found to be non significant. The sensitivity of SELISA was determined to be 94.85% whereas the specificity was 90.85% in comparison to IFAT. The agreement between the two tests by kappa statistics at 95% confidence interval revealed κ- value of 0.853 that depicts almost a perfect degree of agreement. The findings employing experimental as well as test sera from cattle and buffalo from some of the tick infested zones of India suggested that SELISA could be a useful tool for seroprevalence studies on babesiosis, as the test is less cost intensive with high levels of sensitivity and specificity.