‘Relationship between unimproved household sanitation facilities and malaria infection among under‑five children in Nigeria: insights from Malaria Indicator Survey 2021’, by Asifat et al, in this weeks Malaria World has interesting insights on factors associated with malaria. They found that the type of toilet facility, unimproved versus improved was strongly associated with occurrence of malaria, measured with RDT (rapid diagnostic tests) on children under five years, (3.766 odds ratio). However, this was not significantly associated with malaria (1.297, 95% Confidence interval 0.898–1.875) after adjusting for socioeconomic and demographic factors.
Improved sanitation means flush toilets and unimproved includes pit latrines without slabs, open defecation, and other forms. There is a strong association with occurrence of malaria, but correlation does not indicate causation. Because as rightly pointed out by the authors, unimproved sanitation is associated with poverty, rural residence, and less maternal education. Poor children with less educated mothers living in rural locations are more likely to have malaria and to only have unimproved sanitation facilities. Other factors that were found to be associated with occurrence of malaria were accommodation with unimproved wall materials and roof materials. These factors are also associated with poverty.
One factor that surprised me was that the drinking water source was not significantly associated with occurrence of malaria. Drinking water sources were classified according to the WHO/UNICEF Joint Monitoring Programme (JMP) framework: 4.5% safely managed water (piped into dwelling), 64.0% basic water (protected wells, boreholes, public taps), 24.4% unimproved water (unprotected wells, tanker trucks), and 7.1% surface water (rivers, lakes, canals). Surface water compared to safely managed water has 3.183 times more malaria. However, both are small numbers in the sample and are also associated with wealth. Most subjects have basic water or unimproved water, the quality of which is unknown without testing.
So, what is the factors that increase susceptibility to malaria? It is most likely related to poverty. There is no discussion of nutrition in this paper. The quality of nutrition is likely associated with wealth and the education level of the mother. It is a factor that merits more attention.