Fig. 1.

Phases of the P. vivax life cycle targeted by various antimalarial compounds. Infected mosquitoes take up a human blood meal and inject sporozoites into the bloodstream. Sporozoites then migrate to the liver, where they either become hepatic schizonts which release merozoites into the bloodstream, or become dormant hypnozoites. Merozoites in the blood infect RBCs, where they develop from rings, to trophozoites and finally to mature schizonts. The majority of antimalarials target this intraerythrocytic stage. *Antimalarial compounds are generally thought to be more active against P. vivax gametocytes compared to P. falciparum, however, this may in part be an indirect effect through targeting asexual stage parasites and requires further study. A subset of intraerythrocytic parasites will develop into sexual stage gametocytes which are then taken up by the mosquito during a blood meal where they eventually develop into sporozoites to begin the cycle anew. Most antimalarials target the blood stage, while primaquine (PQ) and tafenoquine (TQ) also target the liver stage, including hypnozoites. PQ and TQ are required to achieve “radical cure” to completely eliminate the parasite. Adapted from “P. vivax Replication Cycle”, by BioRender.com (2020).