Abstract

Objective: To evaluate the features and risk factors associated with recrudescent infections that arose following artemisinin-based combination drug treatment of the primary infections. Methods: The clinical features and risk factors associated with subsequent recrudescence of primary Plasmodium falciparum infections were evaluated in 37 of 877 children following artesunate or artemisinin-based combination treatments (ACTs). Recrudescence was determined by polymerase chain reaction. Results: Compared to children with sensitive infections, children with recrudescent infections had significantly higher gametocytaemia and proportion with parasitaemia >50 000/毺 L. Compared with primary infections, recrudescent infections that arose from primary infections were accompanied by significantly fewer symptoms, lower body temperatures and asexual parasitaemias. In age- and gender- matched children with and without recrudescence, declines in parasitaemias following treatment were monoexponential but elimination half-life of parasitaemia was significantly longer in children with recrudescence. In a multiple regression model, at enrolment, 3 factors were independent risk factors for subsequent recrudescence of primary infections: parasitaemia 曒50 000/毺 L [adjusted odds ratio (AOR)=2.63, 95% confidence interval (CI): 1.17-5.90, P=0.018], parasite clearance time 曒2 days (AOR=2.47, 95% CI: 1.24-4.90, P=0.04) and treatment with artesunate compared with ACTs (AOR=2.35, 95% CI: 1.08-5.12, P=0.03). Conclusions: Recrudescent infections following artesunate or ACTs differ significantly from the primary infections from which they arose and have implications for malaria control efforts in Sub-Saharan Africa where ACTs are now first-line treatments.

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