Abstract: We have developed a modified indirect ELISA (MI-ELISA) using the spherical body protein-4 (SBP4) of Babesia bovis to detect antibody against diverse isolates through all infection stages in cattle. This SBP4 MI-ELISA was evaluated for sensitivity and specificity against field sera and sera from cattle infected experimentally with various doses and isolates as well as in detecting acute and persistent infection. The diagnostic specificity of the SBP4 MI-ELISA using IFA-negative sera was 100%, significantly higher than the RAP-1 cELISA (90.4%); the diagnostic sensitivity of the SBP4 MI-ELISA was 98.7% using the IFA-positive sera, in contrast to that of the RAP-1 cELISA at 60%. Results demonstrate excellent diagnostic sensitivity and specificity of the novel SBP4 MI-ELISA for cattle with acute and long-term carrier infections. Use of the SBP4 MI-ELISA assay in countries that have B. bovis-endemic herds will be pivotal in preventing the spread of this disease to non-endemic herds.

Abstract: We have developed a modified indirect ELISA (MI-ELISA) using the spherical body protein-4 (SBP4) of Babesia bovis to detect antibody against diverse isolates through all infection stages in cattle. This SBP4 MI-ELISA was evaluated for sensitivity and specificity against field sera and sera from cattle infected experimentally with various doses and isolates as well as in detecting acute and persistent infection. The diagnostic specificity of the SBP4 MI-ELISA using IFA-negative sera was 100%, significantly higher than the RAP-1 cELISA (90.4%); the diagnostic sensitivity of the SBP4 MI-ELISA was 98.7% using the IFA-positive sera, in contrast to that of the RAP-1 cELISA at 60%. Results demonstrate excellent diagnostic sensitivity and specificity of the novel SBP4 MI-ELISA for cattle with acute and long-term carrier infections. Use of the SBP4 MI-ELISA assay in countries that have B. bovis-endemic herds will be pivotal in preventing the spread of this disease to non-endemic herds.