Anti-folate drug resistance in Africa: meta-analysis of reported dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) mutant genotype frequencies in African Plasmodium falciparum parasite populations

Table 4 Snapshot of data summarized by maps and time plots

	*dhfr* triple mutant genotype (N51I, C59R, S108N)	*dhps* double mutant genotype (A437G, K540E)
Number of studies	159	94
Mean year of study conducted	2000.79	2001.08
Std Dev year of study conducted	3.35	3.40
Percentage of studies in top three countries^	43.4%	41.5%
Percentage of studies conducted in East Africa†	67.3%	74.5%
Percentage of studies conducted in West Africa†	32.7%	25.5%
Number of total isolates examined	14316	7959
Average number of isolates sampled per study	91.2	84.7
Percentage of total isolates carrying genotype**	54.6%	33.7%
Percentage of isolates carrying genotype in East Africa†**	56.1%	44.3%
Percentage of isolates carrying genotype in West Africa†**	51.5%	3.0%

^ This value serves as an indicator for the clustering of studies: Top three countries reporting dhfr triple mutant genotype are: Kenya, Tanzania, and Cameroon; Top three countries reporting dhps double mutant genotype are: Kenya, Tanzania, and Mozambique
** Weighted average of genotype prevalence, raw data taken from (Additional File 2)
† East and West Africa were defined by the longitudinal line at 22.5°E

ISSN: 1475-2875