Similarly efficacious anti-malarial drugs SJ733 and pyronaridine differ in their ability to remove circulating parasites in mice.

Background: Artemisinin-based combination therapy (ACT) has been a mainstay for malaria prevention and treatment. However, emergence of drug resistance has incentivised development of new drugs. Defining the kinetics with which circulating parasitized red blood cells (pRBC) are lost after drug treatment, referred to as the "parasite clearance curve", has been critical for assessing drug efficacy; yet underlying mechanisms remain partly unresolved.

Quantification of host-mediated parasite clearance during blood-stage Plasmodium infection and anti-malarial drug treatment in mice.

A major mechanism of host-mediated control of blood-stage Plasmodium infection is thought to be removal of parasitized red blood cells (pRBCs) from circulation by the spleen or phagocytic system. The rate of parasite removal is thought to be further increased by anti-malarial drug treatment, contributing to the effectiveness of drug therapy. It is difficult to directly compare pRBC removal rates in the presence and absence of treatment, since in the absence of treatment the removal rate of parasites is obscured by the extent of ongoing parasite proliferation.