Fig. 3

Principal components analysis biplot of the Schistosoma spp. cercariae allele frequencies shed from Bulinus spp. PCA produced using 6 microsatellite loci (excluding 3 Schistosoma haematobium-specific loci) of Schistosoma spp. cercariae shed from Bulinus spp. collected in the Niger River Valley (186 observations). The cumulative proportion of explained variation is 19.8% for the first two principal components (PC1: 14.1%; PC2: 5.7%). Observations are coloured by Schistosoma species profile (see Additional file 1: Table S1)