High prevalence and risk of malaria among asymptomatic individuals from villages with high rates of artemisinin partial resistance in Kyerwa district, North-western Tanzania.

BackgroundTanzania adopted and has been implementing the World Health Organization (WHO) recommended interventions to control and eventually eliminate malaria. However, malaria is still a leading public health problem and the country experiences heterogeneous transmission; but the drivers of these patterns are not clearly known. This study assessed the prevalence and risk of malaria infections among asymptomatic individuals living in a hyperendemic area which has high prevalence of artemisinin partial resistant parasites in Kyerwa District of Kagera region, North-western Tanzania. MethodsThis was a community-based cross-sectional survey that recruited participants from five villages of Kyerwa district in Kagera region. Demographic, anthropometric, clinical, parasitological, types of houses inhabited and socio-economic status (SES) data were collected using electronic capture tools running on Open Data Kit (ODK). Risk factors associated with malaria infections were determined by univariate and multivariate logistic regression and the results were presented as crude (cOR) and adjusted Odds Ratio (aOR), with 95% confidence intervals (CI). ResultsA total of 4,454 individuals were tested using malaria rapid diagnostic tests (RDTs) and 1,979 (44.4%) had a positive test. The prevalence of malaria varied from 14.4% to 68.5% with significant differences among the villages (p<0.001). The prevalence and risk of malaria infections were significantly higher in males (aOR =1.25, 95% CI: 1.06 - 1.48, p=0.04), school children ((aged 5 - 10 years, aOR =4.09, 95% CI: 3.39 - 5.10, p<0.001) and (10-15 years, aOR=4.40, 95% CI: 3.46 - 5.59, p<0.001)) and among individuals who were not using bed nets (aOR =1.29, 95% CI: 1.10 - 1.42, p=0.002). Other risks of malaria infections included lower SES (aOR=1.27, 95% CI:1.04 - 1.55, p<0.001) and living in houses with open windows (aOR=1.26, 95% CI: 1.03 -1.54, p=0.024). ConclusionThis study showed high prevalence of malaria infections and high heterogeneity at micro-geographic levels. The risk of malaria infections was higher in school children, males, individuals who did not use bed nets, and among participants with low SES or living in poorly constructed houses. These findings provide important baseline data in an area with a high prevalence of artemisinin partial-resistant parasites and will be utilized in future studies to monitor the trends and potential spread of such parasites.