The chief source of nutrients is the haemolymph in which the oocyst develops. Sporoblasts form, and sporozoites bud off. After the cyst ruptures, the sporozoites escape into the haemocoele and migrate to and penetrate salivary gland cells, where they lie in vacuoles for up to 59 days. These sporozoites develop and become up to 1000 times more infective than when in the oocyst. They are more antigenic, and bear circumsporozoite polypeptide on their plasmalemma.
Sporozoite motility is involved in their invasion of cells and escape from the salivary gland.
They posses a complex pellicle, which is responsible for motility, and this pellicle contains circumsporozoite protein. The apical penetrating region contains extensions of the microneme ducts which release an agent which interacts with host cell plasma membrane during penetration. Now the sporozoites must begin their evasion of the host defences, possibly by binding serum proteins for 'camouflage'. All sporozoites have left the peripheral circulation system within 45 minutes. The DNA mapping of the 14 chromosomes and the discovery of genes, antigens, and their functionality provide vital clues to help us find a means to combat the spread of malaria.