Evaluation of an Elisa Kit in the Serological Diagnosis of Babesia Bovis for Epidemiological Studies

EVALUATION OF AN ELISA KIT IN THE SEROLOGICAL DIAGNOSIS OF BABESIA BOVIS FOR EPIDEMIOLOGICAL STUDIES. An enzyme linked immunosorbent assay (ELISA) kit for detect antibodies to Babesia bovis, an intraerytrocitic bovine parasite was evaluated using known negative and positive samples and the results were compared with an indirect immunofluorescent antibody test (IFAT). Results obtained with field samples were used to estimate seroprevalence of B. bovis in an endemic area to the cattle tick (Boophilus microplus) vector of bovine babesiosis. Percentage of positivity (PP) values (optical density of tested serum/mean optical density of positive control) on 274 negative samples, had major values ranged in the frequency of 4.0 to 7.0 PP. Comparison between ELISA and IFAT showed an agreement of 93.3% on field sera samples, collected in areas of low, good and high soil fertility in the region of Bagé (31 20’13’’S, 54 06’ 21’’W), RS, Brazil. From 5,082 tested sera, 3,751 (73%) were positive for B. bovis antibodies. No significant difference (p>0.05) was observed between results from calves living in areas of low and good soil fertility (80 and 82% of seroprevalence, respectively). However, calves living in soil of high fertility showed a minor inoculation rate for B. bovis, (63% of seroprevalence) indicating needs of measures to prevent losses due to babesiosis.