Prevalence and risk factors associated with malaria infections at a micro-geographic level in three villages of Muheza district, north-eastern Tanzania

Background Despite a recent reduction in malaria morbidity and mortality, the disease remains a major cause of morbidity and mortality in Tanzania. However, the malaria burden is heterogeneous with a higher burden in some regions compared to others, suggesting that stratification of malaria burden and risk/predictors of infections is critical to guide the proper use of the current and future interventions. This study assessed the prevalence and predictors of /risk factors associated with malaria infections at micro-geographic levels in three villages of Muheza district, Tanga region, north-eastern Tanzania. Methods A cross-sectional community survey was conducted in three villages; Magoda, Mpapayu, and Mamboleo in Muheza district, Tanga region, north-eastern Tanzania in June 2021. Participants demographic, anthropometric, clinical, and malaria protection data were collected during the survey and combined with census data collected in 2013 including housing conditions and socio-economic status (SES). Finger prick blood samples were taken for parasite detection using both microscopy and rapid diagnostic tests (RDT). A generalised estimating equation (GEE) was used to determine the association between the prevalence and predictors/risk factors of malaria infections. Results The survey covered 1,134 individuals from 380 households and most of them (95.2%) reported that they slept under bed nets the night before the survey. By both microscopy and RDT, the prevalence of malaria infections was 19.2% and 24.3%, respectively. The prevalence was significantly higher among school children (aged >5 to 15 years, with 27.3% by microscopy and 37.6% by RDTs) compared to under-fives and adults (aged 15 years and above (p<0.001)). Individuals with a history of fever within 48 hours before the survey and those with fever at presentation (auxiliary temperature above 37.5oC) were more likely to have malaria infections by microscopy (AOR = 1.16; 95% CI, 1.10 to 1.22; p<0.001) and RDTs (AOR = 1.18; 95% CI, 1.13 to 1.23; p<0.001). Participants with high SES and living in good houses (with closed eaves and/or closed windows) were less likely to be infected by malaria parasites as detected by microscopy (AOR =0.97; 95% CI, 0.92 to 1.02; p=0.205) and RDTs (AOR = 0.91; 95% CI, 0.85 to 0.97; p<0.001). Among the three villages, the prevalence of malaria by microscopy ranged from 14.7% to 24.6% and varied significantly but without any clear patterns across villages indicating high heterogeneity and random distribution of malaria at micro-geographic levels (p=0.001). Conclusion The villages had high prevalence and predictor/risk factors risk of malaria infections including age, sex (male), fever, SES, and housing conditions. High prevalence and risk were among school children (aged above 5 to 14 years), males, individuals with low SES and a history of fever within 48 hours before the survey, or fever at presentation (with auxiliary temperature above 37.5oC). The prevalence varied over short distances at micro-geographic levels suggesting that causes of such variations need to be established and considered when designing and implementing targeted malaria control interventions. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported in full by the Bill & Melinda Gates Foundation [grant number 002202]. Under the grant conditions of the Foundation, a Creative Commons Attribution 4.0 Generic License has already been assigned to the Author Accepted Manuscript version that might arise from this submission. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The ethical approval for conducting this study was obtained from the Medical Research Coordinating Committee of the National Institute for Medical Research in Tanzania. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The dataset of this study is available from the corresponding author upon a reasonable request from the corresponding author together with an institutional approval by NIMR and signing of a data transfer agreement (DTA) between the donor and recipient.