Repurposing of the Malaria Box for Babesia microti in mice identifies novel active scaffolds against piroplasmosis

Abstract Background An innovative approach has been introduced for identifying and developing novel potent and safe anti-Babesia and anti-Theileria agents for the control of animal piroplasmosis. In the present study, we evaluated the inhibitory effects of Malaria Box (MBox) compounds (n = 8) against the growth of Babesia microti in mice and conducted bioinformatics analysis between the selected hits and the currently used antibabesial drugs, with far-reaching implications for potent combinations. Methods A fluorescence assay was used to evaluate the in vivo inhibitory effects of the selected compounds. Bioinformatics analysis was conducted using hierarchical clustering, distance matrix and molecular weight correlation, and PubChem fingerprint. The compounds with in vivo potential efficacy were selected to search for their target in the piroplasm parasites using quantitative PCR (qPCR). Results Screening the MBox against the in vivo growth of the B. microti parasite enabled the discovery of potent new antipiroplasm drugs, including MMV396693 and MMV665875. Interestingly, statistically significant (P