Fig. 3: Individual P. falciparum oocysts contain a large number of sporozoites.

a Schematic of oocyst development assessment. The midguts of P. falciparum infected mosquitoes were dissected and stained with mercurochrome between days 7 to 12 post infection. b Representative images of P. falciparum infected midguts on days 7 and 11 post infection. Scale bars: 100 µm. Insets show zoomed in images of oocysts. Scale bars: 50 µm. c P. falciparum oocyst diameters on days 7–12 post infection. Each dot represents one oocyst and bars indicate the mean (****P < 0.0001; ns, not significant, P > 0.5 [one-way ANOVA followed by Tukey’s test]). Data are from two independent mosquito cycles and the numbers of midguts analyzed are day 7, n = 19; day 9, n = 20; day 11, n = 27; day 12, n = 16) d Schematic of sporozoite quantification in single oocysts. On days 11 and 12 post-infection, P. falciparum-infected mosquito midguts were stained with mercurochrome to identify oocysts. Single oocysts were isolated by microscopy-guided dissection, placed on slides for diameter measurements and then transferred to a tube for sporozoite quantification by qPCR. e Representative image of an isolated single oocyst. Scale bar: 50 µm. f Sporozoite quantity correlates with oocyst diameter: Spearman correlation, ρ = 0.75; P < 0.0001 (two-tailed). Each dot represents a single oocyst (data obtained from three independent mosquito cycles, total n = 26). g Violin plot illustrating sporozoite quantity in single oocysts using the dataset in panel f. The thick bar indicates the median, and the thin bars indicate the upper and lower quartiles.