BackgroundDeclines in malaria incidence attributed to the implementation of control strategies have been reported in many African countries. The declines are often accompanied by a shift in clinical burden to older children. In Mali, artemisinin-based combination therapy (ACT) was introduced in 2004, and Long-lasting insecticide-treated nets (LLINs) have been partially distributed free of charge since 2007. In Bandiagara, a study conducted from 2009 to 2013 showed a stable incidence of malaria compared to 1999 despite the use of ACTs and LLINs. Since 2016, seasonal malaria chemoprevention (SMC) has been scaled up across the country. In addition to these strategies, the population of Bandiagara benefited the universal bed net coverage and indoor residual spray (IRS) implementation in 2017 and 2018.This study aimed to measure the incidence of malaria in the context of recent scaling-up of control strategies.MethodsA cohort of 300 children aged 6 months to 15 years was followed from October 2017 to December 2018 in Mali. Monthly cross-sectional surveys were done to measure the prevalence of malaria infection by microscopy and anaemia. The study outcomes included the monthly prevalence of malaria infection and the incidence of symptomatic malaria.ResultsThe incidence of symptomatic malaria was 0.5 episodes/person-year. The average prevalence of malaria parasitaemia was 6.7%. The incidence was higher in the oldest age group than the youngest one (0.6 episodes/person-year in children above 10 years vs 0.29 in 6 months to 5 years age group).ConclusionsThis study showed a reduction of malaria incidence compared to 1999 and 2009-2013. An age shift in the susceptibility to malaria was also observed; older children experienced more clinical malaria than younger ones. These findings suggest to extend malaria control efforts to older children.

Background: In 2006, the National Malaria Control Program (NMCP) in Mali recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. Since the introduction of ACT, few reports are available on the level of resistance of Plasmodium falciparum (P. falciparum) to antimalarial drugs in Mali. Dihydroartermisinin is the active metabolite of artemisinin derivatives. Here, we conducted an ex-vivo drug sensitivity testing in a rural area of southern Mali, namely the Kéniéroba village from 2016 to 2017. Methods: Seventy-five (75) isolates of P. falciparum were successfully evaluated for ex-vivo sensitivity to key anti-malarial drugs, namely chloroquine (CQ), quinine (QN), amodiaquine (AQ), mefloquine (MQ), lumefantrine (LUM), dihydroartermisinin (DHA) , and piperaquine (PPQ). P. falciparum sensitivity to these drugs was assessed using the World Wide Antimalarial Resistance Network (WWARN) SYBR-GREEN method of inhibitory concentration of 50% (IC50) determination. Reduced sensitivity to antimalarial drugs was defined as IC50 less than the WWARN standard IC50. Results: The proportion of resistant P. falciparum isolates was 20.2% for CQ, 40.5% for QN, 6.8% for AQ, and 1.3% for MQ. All tested P. falciparum isolates were sensitive to LUM, DHA, and PPQ. A statistically significant correlation was found between QN and AQ IC50 values (r = 0.80; r2 = 0.64, P<0.0001). Conclusions: P. falciparum isolates were sensitive to all ACT derivates tested in Kenieroba in Mali. In contrast, P. falciparum isolates were resistant to, CQ, QN, and AQ as evidenced by high IC50 to these drugs.