Figure 3

Parasite multiplication rates (with 95% confidence intervals) of new P. falciparum clinical isolates, sampled from patients in three West African countries (GUI, Guinea; SEN, Senegal, MAL, Mali). (A) Eleven isolates were analysed after growth in culture for at least two weeks (between 16 and 32 days) prior to assay. Exponential growth was measured over 4 days using a general linear model approach. All assays were conducted with biological triplicates in separate flasks with different donor erythrocytes, except for SEN232 which was assayed in duplicate. Six of the isolates (SEN232, GUI246, MAL247, GUI249, MAL250, SEN251) were assayed in medium supplemented by Albumax and serum, whereas the other five were assayed by medium with Albumax alone as noted in the Materials and Methods (results were similar for the two groups, Mann-Whitney test P = 0.90). As a control, the laboratory adapted clone 3D7-HT-GFP (here labelled ‘3D7′) was tested in parallel in each assay, yielding a consistent multiplication rate of approximately 8 fold per 48 hours. (B) Four of the clinical isolates cultured for longer periods were assayed at three different time points after culture initiation (up to 76 or 100 days for each isolate). These showed no significant changes in multiplication rate over time in culture. Assays were conducted with biological triplicates, except for the last cultured time point for which the assay was conducted in duplicate.