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Abstract: Congo-Brazzaville has recently adopted artesunate-amodiaquine as the first-line antimalarial drug to replace chloroquine. Before the implementation of this new strategy, we conducted several clinical studies to assess the therapeutic efficacy of former, classical first-line antimalarial drugs in the city of Brazzaville, in which reside about 30% of the Congolese population. From 2003 to 2005, non-randomised trials were conducted to evaluate the efficacy of sulfadoxine-pyrimethamine (SP) (n =97 patients), amodiaquine (AQ) (n =62 patients), and the combination of sulfadoxine-pyrimethamine–amodiaquine (n =54 patients) in children aged between 6 months and 5 years with uncomplicated malaria using the 2003 WHO guidelines during the 28-day follow-up period. After excluding new infections by PCR, the proportion of treatment failure on day 28 was 30.2% (95% confidence interval, 19.2–43.0%) for sulfadoxine-pyrimethamine, 34.8% (95% confidence interval, 21.4–50.2%) for amodiaquine, and 14.2% (95% confidence interval, 5.9–27.2%) for sulfadoxine-pyrimethamine+amodiaquine combination. Treatment with sulfadoxine-pyrimethamine was associated with an increase of gametocyte charge. These results suggest that neither sulfadoxine-pyrimethamine nor amodiaquine is efficacious as monotherapy and that their combination may not remain effective in the coming years. Based on our results, the implementation of artemisinin-based combination therapy appears to be urgent in the country. [Copyright &y& Elsevier]

Abstract: It has been proposed that ovale malaria in humans is caused by two closely related but distinct species of malaria parasite, Plasmodium ovale curtisi and Plasmodium ovale wallikeri. It was recently shown that these two parasite types are sympatric at the country level. However, it remains possible that localised geographic, temporal or ecological barriers exist within endemic countries which prevent recombination between the genomes of the two species. Here, using conventional and real-time quantitative PCR (qPCR) methods specifically designed to discriminate P. o. curtisi and P. o. wallikeri, it is shown that both species are present among clinic attendees in Congo-Brazzaville, and occur simultaneously both in lake-side and inland districts in Uganda and on Bioko Island, Equatorial Guinea. Thus P. o. curtisi and P. o. wallikeri in these localities are exactly sympatric in both time and space. These findings are consistent with the existence of a biological barrier, rather than geographical or ecological factors, preventing recombination between P. o. curtisi and P. o. wallikeri. In cross-sectional surveys carried out in Uganda and Bioko, our results show that infections with P. ovale spp. are more common than previously thought, occurring at a frequency of 1–6% in population samples, with both proposed species contributing to ovale malaria in six sites. Malaria elimination programmes in Africa need to include strategies for control of P. o. curtisi and P. o. wallikeri. [Copyright &y& Elsevier]