The primary screen was carried out by comparing quantities of DNA in treated and control cultures of Plasmodium falciparum in human erythrocytes after 72 h incubation with a fixed concentration of 7 μM of the test compounds.. The secondary potency determination was made by using the same assay in a dose-response mode with 12 concentrations varying from 10 μM to 5 nM. Chemical sensitivities of the human cell lines and T. brucei were determined by measuring their ATP content (Cell Titer Glo, Promega).T. gondii parasites expressing luciferase were cultured and drug sensitivity was determined by luminescence; L. major promastigotes drug susceptibility (Alamar Blue assay, Promega). Chemicals were assayed for hemozoin formation inhibition17 (link), PfDHOD15 (link), FP-227 (link) activities based on previously described methods. Thermal shift assays were done at compound concentrations of 25 μM and protein concentrations of 100 μg/ml. All data processing and visualization, and chemical similarity and substructure analysis was performed using custom programs written in the Pipeline Pilot platform (Accelrys, v.7.0.1) and the R program.26 A complete description of the methods can be found in Supplementary Information.