Prevalence and risk factors associated with infections caused by Plasmodium parasites at micro-geographic level in three villages of Muheza district in Tanga region, north-eastern Tanzania

BACKGROUND: Malaria burden in Tanzania has recently become heterogeneous, with a higher burden in some regions than in others. This suggests that stratification of transmission intensities and predictors of risk factors associated with infections caused by Plasmodium parasites is critical to guide proper use of the current and future interventions. This study assessed the prevalence and predictors of /risk factors associated with Plasmodium parasite 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 June 2021 and covered three villages: Magoda, Mpapayu, and Mamboleo from Muheza district in Tanga region. Finger prick blood samples were taken for parasite detection using microscopy and rapid diagnostic tests (RDTs). A generalized estimating equation (GEE) was used to determine the association between the prevalence and predictors/risk factors of Plasmodium parasite infections. RESULTS: The survey recruited 1134 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 RDTs, the prevalence of infections caused by Plasmodium parasite 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) (p < 0.001). Participants from households with closed eaves were less likely to be infected by Plasmodium parasites as detected by RDTs (AOR = 0.91; 95% CI, 0.85-0.97; p < 0.001). Among the three villages, the prevalence by microscopy ranged from 14.7% to 24.6% and varied significantly across villages, indicating high heterogeneity and random distribution of malaria at micro-geographic levels (p = 0.001). For RDTs, the prevalence ranged from 24.1% to 34.9%, but the differences of the prevalence in the three villages were not statistically significant (p = 0.422). CONCLUSION: The study villages had a high prevalence, and the risk of Plasmodium parasite infections was higher in school children (aged 5 to < 15 years). The prevalence and risk of infections varied significantly among the villages which are located next to each other suggesting high variations at micro-geographic levels. These findings will be useful in future planning of malaria stratification and targeting of interventions to high-risk groups and areas, as part of the strategies for malaria elimination by 2030.