Figure 1.

Change in Plasmodium falciparum dihydrofolate reductase (DHFR; A) and dihydropteroate synthase (DHPS; B) haplotype prevalence over 3 periods in the history of sulfadoxine-pyrimethamine (SP) use in Ndirande, Malawi. Prevalence is calculated as the percentage of individuals with a given haplotype. The 3 periods consisted of a period of high SP use (1999–2001), a transitional period (2007–2008), and a period of low SP use (2012). Black bars indicate statistically significant differences. Error bars represent 95% confidence intervals. The asterisks indicate the use of the Yates correction.