CPAP and infection: To assess the effect of sas4 gene deletion on oocyst development, the number of GFP-positive oocysts on the mosquito gut wall was counted in mosquitoes fed with either ΔSAS4 or WT-GFP parasites; there was no significant difference in the number or size of ΔSAS4 oocysts compared with WT-GFP controls at 14- and 21-d post-infection (Fig 4E and F).