OSCP is involved in oocyst wall formation and maintenance. a Number of oocysts per midgut at 5, 9, and 14 days after an infected blood meal. The horizontal bars show the median value. The inhibition of oocyst number was calculated using (1-KO-oocyst median number/WT-oocyst median number) × 100. Number of independent experiments: day 5 and day 9 in duplicate and day 14 in triplicate. Mann–Whitney U test: **P < 0.01, ***P < 0.001. b Oocyst diameter per midgut at days 5, 9, and 14. Welch’s t-test: *P < 0.01. c Transmission electron microscopic images of oocysts at day 17. O: oocyst; C: oocyst capsule; M: mosquito tissue; S: sporozoite. d Upper panels (mercurochrome staining): examples of normal and degenerated oocysts. Lower panel: Proportion of WT and KO normal oocysts at day 6–7. Mann-Whitney U test: *P < 0.05.