Study of Controlled Human Plasmodium Vivax Infection

Two healthy human volunteers are exposed to the bites of five infectious mosquitoes per participant (by placing their forearms over the pot containing mosquitoes) for 5-10 minutes. Fed mosquitoes (as indicated by the presence of a blood meal in the abdomen) are individually dissected and assessed for sporozoite load (graded 0 to +4; a gland rating of +2 or more, representing 10 or more observed sporozoites, qualifies as being infectious). If, by this method the volunteer is found to have been inoculated by less than five infected mosquitoes, further mosquitoes are allowed to feed on the volunteer until a total of 5 appropriately infected mosquitoes have fed. The bite-challenge procedure continues until the subject has been bitten by 5 infectious mosquitoes.

Collection of 250mL of P. vivax-infected blood from each volunteer when a threshold parasitaemia/ symptoms are met