(A) Schematic representation of sphingomyelin cycle. Ceramide is produced via the hydrolysis of sphingomyelin via a neutral sphingomyelinase, which is inhibited by GW4869. (B) Dd2 parasites were subjected to 72-hour drug assays with GW4869 ± 50 µg/ml of lignoceric ceramide. Means±SEM were calculated from four independent sets of duplicates. **p≤0.01. (C) Parasite ABS development was assessed following the addition of 1 µM GW4869 (~170×IC50) to highly synchronized parasites, beginning 8 hpi. Compound was added at time points 8, 16, 24, 32, 40 or 48 hpi. Giemsa-stained smears were counted at every time point, as well as the final 56 hpi time point (experiment performed on two separate occasions). Data are shown for the 8 and 56 hpi time points.