Fluorescence microscopy revealed that c-cap(-) oocysts were markedly reduced in size and numbers as compared to the wild tye. c-cap(-) parasites consistently formed slightly fewer oocysts, i.e. on average 110 ( 42) oocysts per infected mosquito as compared to an average of 213 ( 64) oocysts per infected mosquito for wild type. Up until day 6 oocyst development was comparable between c-cap(-) and wildtype, indicating that initial events in sporogony, including increase of parasite mass and the first few mitotic replications, were unaffected in the mutant. By day 8 c-cap(-) oocysts were significantly smaller in size and arrested their development, when compared to the linear size increase in wildtype oocysts. Quantification of oocyst diameters revealed that c-cap(-) occysts typically reached an average size of 15 m, corresponding to day 8 wild type oocysts. However, few c-cap(-) oocysts reached sizes comparable to wild type. In mutant oocysts only few nuclei corresponding to 4-5 rounds of nuclear divisions and no sporozoites were detected. No formation of sporozoites inside the oocysts.

No formation of sporozoites within the oocyst. No salivary gland sporozoites

No formation of sporozoites within the oocyst. No salivary gland sporozoites. Infected mosquitoes are not able to infect mice.