High prevalence of persistent residual parasitemia on days 3 and 14 after artemether-lumefantrine or pyronaridine-artesunate treatment of uncomplicated Plasmodium falciparum malaria in Nigeria.

Background: Microscopic evaluation of parasite clearance is the gold standard in antimalarial drug efficacy trials. However, the presence of sub-microscopic residual parasitemia after artemisinin-based combination therapy (ACT) needs to be investigated.

Methods: One hundred and twenty (AL: n = 60, PA: n = 60) days 3 and 14 dried blood spots, negative by microscopy were analysed for residual parasitemia using nested PCR.