Abstract
Insecticide resistance in malaria vectors has created an urgent need for alternative, non-insecticidal control tools. In response, a novel window screen, the Three-dimensional (3D) Screen, was developed. Before launching a cluster-randomized controlled trial to evaluate its impact, a baseline study was conducted in 20 hamlets (clusters) from 17 villages in Muheza District, northeastern Tanzania, to assess malaria burden, vector characteristics, and risk factors for infection. Structured questionnaires collected household information; malaria prevalence was measured among 778 children aged 6 months to 14 years using malaria rapid diagnostic tests (mRDTs), and haemoglobin was assessed by HemoCue. Indoor Centers for Disease Control and Prevention (CDC) light traps (LTs) were used for mosquito collections, yielding 14,263 mosquitoes morphologically identified, including 889 Anopheles gambiae sensu lato (s.l.) and 2,013 An. funestus senso lato (s.l.); 2,508 female Anopheles were further analysed by Polymerase chain reaction (PCR). World Health Organization (WHO) cylinder bioassays assessed pyrethroid resistance in An. gambiae s.l., and genotyping targeted the knockdown resistance (kdr)-East (L1014S) mutation. Malaria prevalence was 40.2%, and anaemia affected 55.2% of children. An. funestus s.l. (70.2%) and An. gambiae s.l. (29.8%) comprised the vector population. Mean daily entomological inoculation rates (EIRs) were 0.039 and 0.037 infectious bites per person per night, corresponding to annual EIRs of approximately 14.2 for An. funestus s.l., 13.5 for An. gambiae s.l., and 27.7 combined. Pyrethroid resistance was high, with 24-hour mortality of 56.5% to permethrin and 52.8% to deltamethrin; the kdr-East (L1014S) allele frequency in An. gambiae s.s. was 0.45. Multivariate analysis showed that children aged ≥ 5 years had approximately threefold higher odds of Plasmodium infection than those < 5 years (aOR = 3.03, 95% CI: 2.09–4.40), while sleeping under a bed net was protective (aOR = 0.36, 95% CI: 0.18–0.70). Cluster-level variance accounted for 19.5% of infection risk, highlighting community-level factors. Persistent transmission, high anaemia prevalence, and widespread insecticide resistance underscore the limitations of current measures and the need for integrated interventions, including novel non-insecticidal tools such as the 3D-Screen.
Data availability
All datasets supporting the conclusions of this study are provided within the article and its supplementary material (Additional file 1: Supplementary_materials.pdf).
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Acknowledgements
The authors extend their sincere acknowledgements and gratitude to the residents of Muheza district for participating in the study. The authors are equally grateful to the village chair, committee members, providing necessary arrangements during the study. The authors would also like to thank logistic and technical staff members, drivers, field technicians and insectary technicians from NIMR, Amani centre for providing great assistance during the study.
Funding
The study was funded through the financial support from Jane ja Aatos Erkon Säätiö (Grant no. 4244-67694). Open access funded by Helsinki University Library.
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SK, WK, SM, and AK conceived and designed the study. SK supervised field activities and data collection. VM oversaw the epidemiological survey, and MF and JM supported the laboratory analyses. VM and FM facilitated community outreach and sensitization meetings. SK performed the data analysis and, together with AK, drafted the manuscript. WK, SM, and AK provided guidance and supervision throughout the study. AK oversaw the overall conduct of the study and, together with SM, secured funding. All authors reviewed and approved the final manuscript.
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This study was approved by the Medical Research Coordinating Committee (MRCC) of the National Institute of Medical Research (NIMR) (Ref: NIMR/HQ/R.8a/Vol. IX/2399), Tanzania.
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Kathet, S., Bwana, V.M., Fereji, M.A. et al. Baseline malaria burden and pyrethroid resistance in Muheza, Tanzania informing a cluster randomized trial of the 3D window screens. Sci Rep (2026). https://doi.org/10.1038/s41598-026-46221-6
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DOI: https://doi.org/10.1038/s41598-026-46221-6
