A model for Plasmodium falciparum sporozoite challenge and very early therapy of parasitaemia for efficacy studies of sporozoite vaccines.

Plasmodium falciparum parasitaemias were induced in four non-immune volunteers by the bites of mosquitoes infected from cultured gametocytes. Radical cure was accomplished before three of the four volunteers developed clinical malaria. Despite very low peak levels of parasitaemia, the plasmodium was recultured from the blood of all volunteers. This volunteer model of early detection of parasitaemia and prompt treatment will contribute to the safe and practical efficacy testing of sporozoite vaccines, thus facilitating the selection of candidate vaccines for large scale definitive field trials.