The Impact of Periodic Distribution Campaigns of Long-Lasting Insecticidal-Treated Bed Nets on Malaria Vector Dynamics and Human Exposure in Dielmo, Senegal.

The implementation of long-lasting insecticidal-treated bed nets (LLINs) has contributed to halving the mortality rate due to malaria since 2000 in sub-Saharan Africa. These tools are highly effective against indoor-feeding malaria vectors. Thus, to achieve the World Health Assembly's new target to reduce the burden of malaria over the next 15 years by 90%, it is necessary to understand how the spatiotemporal dynamics of malaria vectors and human exposure to bites is modified in the context of scaling up global efforts to control malaria transmission. This study was conducted in Dielmo, a Senegalese village, after the introduction of LLINs and two rounds of LLINs renewals. Data analysis showed that implementation of LLINs correlated with a significant decrease in the biting densities of the main malaria vectors, Anopheles gambiae s.l. and Anopheles funestus, reducing malaria transmission. Other environment factors likely contributed to the decrease in An. funestus, but this trend was enhanced with the introduction of LLINs. The bulk of bites occurred during sleeping hours, but the residual vector populations of An. gambiae s.l. and An. funestus had an increased propensity to bite outdoors, so a risk of infectious bites remained for LLINs users. These results highlight the need to increase the level and correct use of LLINs and to combine this intervention with complementary control measures against residual exposure, such as spatial repellents and larval source management, to achieve the goal of eliminating malaria transmission.

Challenges for malaria vector control in sub-Saharan Africa: Resistance and behavioral adaptations in Anopheles populations.

Over the past decade, global malaria-related mortality has declined dramatically because of combined international actions that have defined and prioritized national and regional efforts to reduce the incidence of malaria, with the ultimate goal of eradication. Vector control strategies using insecticide-treated nets (ITNs) and indoor residual spraying (IRS) in African countries have contributed significantly to the declining incidence of malaria. However, the effectiveness of malaria control is threatened by increasing insecticide resistance and behavioral changes in Anopheles vectors. Thus, there is an urgent need to ensure that future programmes are designed to address these threats and protect the progress made so far in controlling malaria. This review summarizes the current malaria vector control tools and discusses about the critical threats to vector control programme and vector management.