Malaria burden and anti-malarial drug efficacy in Owando, northern Congo

Brice P. Singana, Hervé Bogreau, Brunelle D. Matondo, Louis R. Dossou-Yovo, Prisca N. Casimiro, Rigobert Mbouka, Kim Yen Ha Nguyen, Bruno Pradines, Leonardo K. Basco, Mathieu Ndounga

In the Republic of Congo, previous epidemiological studies have only been conducted in the south of the country where it is most accessible. Nationally representative data on the efficacy of new anti-malarial tools are lacking in the country. As an initial step to close the gap, clinical efficacy of two artemisinin-based combinations, artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL), was assessed in Owando, a city in equatorial flooded forest in northern Republic of Congo. Under 12 years old febrile children attending public health facilities were screened for malaria parasites using lactate dehydrogenase (LDH)-based rapid diagnostic test (RDT) for malaria and microscopic examination of thick blood films. Patients with at least 1,000 asexual Plasmodium falciparum parasites/µl of blood were clinically examined, included after informed consent, and followed up for 28 days, according to the 2009 World Health Organization protocol. Patients were randomly assigned to co-formulated ASAQ (Coarsucam(®)) or AL (Coartem(®)) treatment groups. Plasmodium falciparum recrudescent isolates were compared to pre-treatment isolates by polymerase chain reaction (PCR) using msp1, msp2, and glurp genes to distinguish between re-infection and recrudescence. Between November 2012 and February 2013, 857 under 12 years old febrile children were screened, of whom 198 (23.1 %) had positive RDT and 167 (19.5 %) positive thick films. ASAQ and AL efficacies were 92.7 and 94.2 % before PCR correction, respectively. After genotyping, the overall efficacy was 100 % for ASAQ and 98.0 % for AL. The data reported here represent partially the burden of malaria in 0-11 years old febrile children examined in public health centres of Owando city and serve as reference for further studies. Both artemisinin-based combinations were highly efficacious in patients under 12 years old with acute uncomplicated malaria. ASAQ was associated with more adverse events, which may reduce compliance in unsupervised treatment. ACTRN12612000940875.