Mass mosquito trapping for malaria control: past successes and future directions

In the context of increasing levels of insecticide resistance, changes in mosquito biting behaviour and drug resistant malaria parasites, mass mosquito trapping for malaria control forms a promising tool to complement long-lasting insecticide-treated nets and indoor residual spraying. Laboratory studies led to the development of synthetic odour baits to lure host-seeking mosquitoes, and these baits have been incorporated into odour-baited trapping systems which have been evaluated under semi-field and field conditions in East Africa. On Rusinga Island, western Kenya, the first ever field evaluation of mass mosquito trapping for malaria control took place between 2012 and 2015. The results showed that mass trapping is associated with reductions in Anopheles funestus populations of 70% corresponded with a 30% reduction in malaria cases among people living in households with the trapping systems, compared to people living in households yet to receive traps. The success of this intervention leads to questions about the next steps in trap development and the feasibility of using traps in a malaria control or elimination context. Development of next generation traps which are cheaper, more durable and require less user-maintenance would take this technology one step closer to a policy recommendation. Adaptation of odour baits and traps to attract malaria vectors in other regions would be advantageous. Combining solar-powered traps with rural electrification programmes forms a promising pathway for the distribution of trapping systems, and expanding the scope of the intervention to include a spatial repellent in a push-pull set-up could increase the efficacy of traps and the degree of personal protection provided. Learning from past successes in mass trapping for vector control leads to exciting prospects.