Agricultural interventions, including cattle production, can potentially improve rural household food production and can enhance micronutrient intakes of animal source foods. Conversely, these intervention can predispose humans to negative health effects that would possibly derail their nutritional benefits. The objective of this study was to establish if these negative external effects exist with respect to cattle as an alternative host to malaria causing mosquitoes in Uganda; and to assess the magnitude of the association between malaria and anemia among children <5 years
We conducted serial panel surveys in 6 rural districts of Uganda obtaining comprehensive household and individual data on demographics, agricultural production, dietary consumption, water and sanitation, health, education, and income producing activities. We measured child anthropometrics, hemoglobin levels, and tested for malaria using rapid diagnostic tests. Multivariate analyses using correlated random effects modeling with control function were employed to account for potential confounding and unobserved heterogeneity.
We conservatively estimate that cattle ownership was significantly associated with a 12% increase in malaria (p<0.05) for children <5 years. Malaria was in turn linked to a 74% increase in child anemia (p< 0.01). Two of four agro-ecologically similar districts had received multiple rounds of indoor residual spraying (IRS) against malaria. In IRS districts, both childhood malaria and anemia prevalence were significantly lower (p<0.001) but cattle ownership enhanced childhood malaria prevalence risk there by 19% (p<0.01) compared to the non-IRS districts.
IRS, which kills indoor anthrophilic mosquitoes, may unmask residual malaria transmission by outdoor zoophilic mosquitoes which feed on both cattle and humans. Efforts to enhance nutrition and health by the agricultural intervention of cattle promotion may need to include livestock-oriented vector control.