Malarial parasites. Coloured scanning electron micrograph of the stomach wall of a mosquito Anopholes stephansii infected with malarial parasites Plasmodium sp. The small rounded objects (blue) covering the outside stomach wall are oocysts, a stage in the life cycle of the parasite. The oocysts grow in size and the contents divide to form sporozoites. On maturity, the oocysts burst and are dispersed through the body cavity. The released sporozoites eventually reach the salivary gland of the mosquito and are transmitted to humans when the female takes a blood meal.