Measurement of Babesia bovis infected red blood cells using flow cytometry

Rapid and accurate tools are needed for high-throughput in vitro antibabesial drug testing. In this study, flow cytometry for the measuring of Babesia bovis in vitro culture, was developed using SYBR Green I and compared against the results of fluorescence-based assay and microscopic assay. A high correlation of measured parasitemia was observed with high R2 value (R2 = 0.9991) between flow cytometry and microscopic analysis. The degree of antibabesial drug sensitivity against B. bovis determined by flow cytometry was 0.424 ± 0.173 μM. Similar to the results of previously published studies involving fluorescence spectrometry-based assay (0.408 ± 0.011 μM) and microscopy-based assay (0.400 ± 0.017 μM). The outcomes of this present study suggest that flow cytometry assay using SYBR Green I can potentially be useful in determining parasitemia and can serve as a rapid alternative method to antibabesial drug testing.