(a) Naive mice were injected i.v. with infected blood and treated daily for 3 days starting 24 h post passage with compound 1o (100 mg kg−1), with methylene blue (MB, 15 mg/kg), or with vehicle (Tw80) as positive and negative controls, respectively. Parasitemia was monitored daily and the mean± s.d. of three independent experiments are plotted. Groups of mosquitoes were fed on mice 24 h after each treatment. (b) Prevalence (percentage of infected mosquitoes) and (c) infection intensity (mean number of parasites per infected midgut) were determined 7 days post infectious blood feeding. The results of four independent experiments were pooled, and the mean±s.e. of the mean is shown (b,c). Significance for differences between treatments was calculated using generalized linear models with treatment, time, and repeats as variables, ***P value <0.001 (a–c). n, number of mosquitoes. (d) Effects of compound 1o on early, mid, and late stage P. falciparum gametocytes. Representative data sets are given (4.5% gametocytaemia) out of three independent experiments. Survival of treated gametocytes was calculated for each concentration relative to parasites exposed to vehicle.