Potential of household environmental resources and practices in eliminating residual malaria transmission: a case study of Tanzania, Burundi, Malawi and Liberia

Background: The increasing protection gaps of insecticide-treated nets and indoor-residual spraying methods against malaria have led to an emergence of residual transmission in sub-Saharan Africa and thus, supplementary strategies to control mosquitoes are urgently required.
Objective: To assess household environmental resources and practices that increase or reduce malaria risk among children under-five years of age in order to identify those aspects that can be adopted to control residual transmission.
Methods: Household environmental resources, practices and malaria test results were extracted from Malaria Indicators Survey datasets for Tanzania, Burundi, Malawi and Liberia with 16,747 children from 11,469 households utilised in the analysis. Logistic regressions were performed to quantify the contribution of each factor to malaria occurrence.
Results: Cattle rearing reduced malaria risk between 26%-49% while rearing goats increased the risk between 26%-32%. All piped-water systems reduced malaria risk between 30%-87% (Tanzania), 48%-95% (Burundi), 67%-77% (Malawi) and 58%- 73 (Liberia). Flush toilets reduced malaria risk between 47%-96%. Protected-wells increased malaria risk between 19%-44%. Interestingly, boreholes increased malaria risk between 19%-75%. Charcoal use reduced malaria risk between 11%-49%.
Conclusion: Vector control options for tackling mosquitoes were revealed based on their risk levels. These included cattle rearing, installation of piped-water systems and flush toilets as well as use of smokeless fuels.

Keywords
malaria risk, residual transmission, household environmental resources and practices, insecticide-treated nets, indoor-residual spraying