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Nationally representative programmatic surveillance of mosquito and human behaviours that influence human exposure to malaria transmission and the impact of vector control across Tanzania
Detection of Supergroup B Wolbachia Strains in Wild Anopheles funestus in South-eastern Tanzania: Implications for Malaria Control
A household randomised-control trial of insecticide-treated screening for malarial control in unimproved houses in Tanzania
Molecular surveillance of malaria in Tanzania: baseline surveillance of vectors that drive persistent malaria transmission in regions with varying transmission intensities
Efficacy of the BiteBarrier transfluthrin emanator against susceptible and resistant malaria and arbovirus vectors in the semi-field system in Tanzania
Temporal Trends in Artemisinin Partial Resistance and Other Antimalarial Drug Mutations in <i>Plasmodium falciparum</i> from Kagera Region, Northwestern Tanzania, 2021–2023
) exhibiting marked spatial heterogeneity, peaking at 38.1% and 48.1%, respectively, in eastern districts. These findings reveal micro-geographic heterogeneity in resistance and ongoing spread, emphasizing the need for district-level surveillance to detect emerging hotspots and guide interventions. Sustained molecular monitoring is critical to inform treatment policy, preserve ACT efficacy, and mitigate the risk of widespread resistance in East Africa.
Implementation and effectiveness of intermittent preventive treatment in school aged children using dihydroartemisinin-piperaquine to reduce malaria burden: an implementation research of a cluster randomised trial in Tanzania
Background: In malaria endemic areas, malaria is a major contributor for half of the mortality in school-aged children (5-15 years old). Most infections are asymptomatic, contributing to anaemia, poor cognitive development, and reduced school performance. School-aged children often show low adherence to preventive and curative measures, and malaria control programs rarely target this group. We evaluated the pilot implementation of intermittent preventive treatment of malaria in schoolchildren (IPTsc) using Dihydroartemisinin-Piperaquine (DP) delivered by schoolteachers, to assess the implementation feasibility and effectiveness on asymptomatic and clinical malaria in a high endemic area in Tanzania. Methods: This study used a cluster-randomised design in which each ward (cluster) was assigned to implement IPTsc or serve as a control. All schoolchildren in primary schools under the intervention arm received three annual rounds of DP aligned with malaria transmission seasons. The primary implementation end point was IPTsc coverage, defined as the proportion of enrolled schoolchildren completing the full DP therapeutic course. For the effectiveness, 12 wards were randomly selected per arm, and one school per ward contributed outcome data. The primary effectiveness endpoints were (1) protective effectiveness of IPTsc on clinical malaria incidence and (2) reduction in parasite prevalence. Data were analysed using cluster-adjusted intention-to-treat (ITT) methods. The study was conducted from February 2020 to July 2021 and is registered with ClinicalTrials.gov (NCT04245033). Findings: Three rounds of DP dispensing covered 127 schools with more than 73,000 schoolchildren. IPTsc coverage reached 77% (range: 69-83%), 73% (64-81%), and 80% (76-85%) in August 2020, November 2020 and March 2021, respectively. DP was well tolerated. In the effectiveness evaluation, 1971 schoolchildren were enrolled in DP arm and 1781 in control arm. After one year, IPTsc reduced clinical malaria incidence by 41% overall (95% CI: 31-49; p < 0.001) and by 54% (95% CI: 44.2-62.6; p < 0.001) in high endemic strata (≥10% baseline prevalence). Parasite prevalence decreased by 81% overall (95% CI: 56.3-100; p < 0.001) ranging from 58% (95% CI: 10.9-100; p = 0.18) in low endemic to 83% (95% CI: 62.7-100; p < 0.001) in high endemic strata. Interpretation: Large scale implementation of IPTsc achieved impact comparable to randomised trials and was operationally feasible and well accepted by communities and teachers. This study sets a benchmark for school-based malaria chemoprevention in Tanzania and provides groundwork for national policy adoption. Funding: The Global Fund, through the Ministry of Health, Tanzania, funded the study.
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.
Varying Malaria Rapid Diagnostic Test Accuracy by Regional Transmission Level and Demographics in Tanzania
Malaria remains a significant global health burden, with approximately 263 million cases across 83 countries. It's essential for malarial infection control to quickly and accurately detect cases. Given the widespread use of malaria rapid diagnostic testing (mRDTs) for case management and surveillance, it's essential to understand test reliability. Clarifying how mRDT results differ from qPCR results, and the nature of additional variance by test manufacturer, will be useful for reducing measurement bias. In comparing 3 national standard mRDTs and a research mRDT with qPCR results from a 2021 cross-sectional study in Tanzania, differences were found by age, gender and regional malaria transmission rate. The research test overall underperformed, with poor sensitivity across transmission strata. In comparing the research mRDT to standard mRDTs, odds ratios suggested transmission intensity may affect mRDT agreement and diagnostic performance. These results offer pertinent information on test accuracy and decrease outcome misclassification for malaria prevalence.
Performance of rapid diagnostic tests, microscopy, and qPCR for detection of Plasmodium parasites among community members with or without symptoms of malaria in villages located in North-western Tanzania
BACKGROUND: Despite the implementation of different control interventions, Plasmodium parasite infections in the communities (among asymptomatic and symptomatic individuals) still play a crucial role in sustaining malaria transmission. This study evaluated the performance of rapid diagnostic tests (RDTs), microscopy, and quantitative PCR (qPCR) in detecting Plasmodium parasites among community members in five villages of Kyerwa district, Kagera region in north-western Tanzania. METHODS: The study used samples and data collected during a community cross-sectional survey of asymptomatic and symptomatic participants (n = 4454) aged ≥ 6 months which was conducted in July and August 2023. Plasmodium parasites were detected using RDTs, microscopy, and qPCR (targeting 18S rRNA gene). The performance of RDTs and microscopy was assessed by sensitivity, specificity, and predictive values, using qPCR as the reference method. Factors affecting the accuracy of these methods were determined using a multivariate logistic regression model. RESULTS: The prevalence of Plasmodium parasite infections among 4454 participants was 44.4%, 32.1%, and 39.8% by RDTs, microscopy, and qPCR, respectively. The prevalence of Plasmodium falciparum, Plasmodium malariae and Plasmodium ovale mono-infection by microscopy was 28.7%, 0.2%, and 0.3%, while by qPCR it was 35.3%, 0.4% and 0.5%, respectively. The geometric mean parasite densities (GMPDs) by microscopy were 642 (95% confidence intervals (CI) = 570-723), 126 (95% CI = 98-162), and 124 (95% CI = 82-160) asexual parasites/µL for P. falciparum, P. ovale spp., and P. malariae, respectively. By qPCR, the GMPDs were 1180 (95% CI = 1032-1349) parasites/µL for P. falciparum, 44 (95% CI = 32-61) for P. ovale spp., and 50 (95% CI = 29-89) for P. malariae. The sensitivity and specificity of RDTs were 94.0% (95% CI = 92.8-95.1%) and 87.5% (95% CI = 86.2-88.7%), respectively, whereas those of microscopy were 74.6% (95% CI = 72.5-76.6%) and 95.2% (95% CI = 94.3-96.0%), respectively. The sensitivity of RDTs, and microscopy was low at very low parasitaemia (< 100 parasites/μL) but increased significantly with increasing parasitaemia, reaching ≥ 99.6% at > 10,000 parasites/μL (p < 0.001). CONCLUSION: High prevalence of Plasmodium parasites was detected, and the performance of RDTs and qPCR was comparable, but microscopy had lower performance. Higher sensitivity of RDTs compared to microscopy indicates that RDTs are effective for detection of infections caused by Plasmodium parasites in routine case management and surveillance in this area with confirmed artemisinin partial resistance (ART-R) and can be utilized in the ongoing plans to develop a response to ART-R.