Community evaluation of three-dimensional window double screens in reducing malaria transmission

ISRCTN ISRCTN87169034
DOI https://doi.org/10.1186/ISRCTN87169034
Secondary identifying numbers 2242/2021
Submission date
18/10/2022
Registration date
28/10/2022
Last edited
25/06/2025
Recruitment status
No longer recruiting
Overall study status
Completed
Condition category
Infections and Infestations
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data
Record updated in last year

Plain English summary of protocol

Background and study aims
Vector-borne diseases such as malaria can be prevented by minimizing man-mosquito contact. This is traditionally achieved by using window screens and bednets. Researchers have developed a mosquito screen that can allow mosquitoes to penetrate it from one side but not the opposite side (i.e., a unidirectional screen). When this screen is used for house screening in a double screen setup, in a way similar to window double glazing in western countries, it will trap mosquitoes trying to enter or escape through the window due to the physical characteristics of the unidirectional screen, so the researchers call it the 3D screen. The window double screen setup was tested in the laboratory and in semi-field experimental hut conditions and was found to be effective in capturing mosquitoes. The aim of this study is to evaluate the effectiveness of the 3D screen in a window double setup in real-world field conditions in reducing mosquito populations and malaria transmission.

Who can participate?
Households in a malaria endemic area

What does the study involve?
The study involves the installation of window double screens on houses followed by measuring indoor mosquito densities and malaria prevalence in five surveys.

What are the possible benefits and risks of participating?
There will be direct benefit for participants as the study will improve the houses of the participants and will provide free insecticide-treated bednets to both intervention and control households. There is always a small risk with blood sampling for malaria screening and this will be minimized by using a finger-prick blood sampling method. Screened children will be provided with malaria diagnosis, free treatment, medical advice, and referral for other symptoms. The 3D-window double screens are designed to reduce mosquito populations and malaria transmission in endemic areas. If the intervention proves to be effective in the real-world situation, it will improve wellbeing, quality of life and the economic status of the targeted areas resulting from less malaria episodes.

Where is the study run from?
The study will be run by the University of Helsinki, Finland, and Amani Research Centre, NIMR, Muheza, Tanzania. It will take place in the Muheza district in north-eastern Tanzania.

When is the study starting and how long is it expected to run for?
May 2019 to August 2021

Who is funding the study?
University of Helsinki and Jane & Aatos Erkko Foundation (Finland)

Who is the main contact?
Dr Ayman Khattab
ayman.khattab@helsinki.fi

Contact information

Dr Ayman Khattab
Principal Investigator

Department of Bacteriology and Immunology
Haartman Institute (Haartmaninkatu 3)
University of Helsinki
P.O.Box 21
Helsinki
00014
Finland

ORCiD logoORCID ID 0000-0002-3980-8379
Phone +358 (0)2941 26 395
Email ayman.khattab@helsinki.fi

Study information

Study designTwo-arm cluster-randomized controlled cross-sectional study
Primary study designInterventional
Secondary study designRandomised controlled trial
Study setting(s)Community
Study typePrevention
Participant information sheet Not available in web format, please use contact details to request a participant information sheet
Scientific titleA cluster-randomized controlled Phase III evaluation of 3D window double screens (3D-WDS) in reducing malaria transmission when combined with pyrethroid-treated long-lasting insecticidal net in north-eastern Tanzania
Study acronym3D-WDS
Study objectivesMosquitoes’ host-seeking behavior could be exploited to trap them in a window double screen trap setup. Mosquito screens that can permit mosquitoes to pass through it from one side but not from the other side, forming a trap in a double screen setup, would be an ideal solution to control mosquito populations and malaria transmission
Ethics approval(s)1. Approved 29/05/2019, National Institute for Medical Research ethics committee (3 Barack Obama Drive, PO Box 9653, 11101 Dar es Salam, +255 (0)222121400, nimrethics@gmail.com), ref: NIMR/HQ/R.8a/Vol.IX/3118
2. Approved 28/04/2022, Helsinki and Uusimaa Hospital District medical research ethics committee (Topeliuksenkatu 5, 00260 Helsinki, +358 (0)403594618, eettiset.toimikunnat@hus.fi), ref: 2242/2021
Health condition(s) or problem(s) studiedMalaria
Intervention20 clusters from 17 villages across Muheza district in the northeast of Tanzania were profiled based on the malaria point prevalence, malaria vector densities and level of insecticide resistance. A strong positive correlation was observed between the number of female Anopheline gambiae population and malaria prevalence therefore cluster selection was primarily based on malaria prevalence. The standard deviation of malaria prevalence from all 20 clusters was calculated and 14 clusters within the standard deviation were selected to participate in the study. Six clusters above and below the standard deviation were not selected to participate in the study. The remaining 14 clusters were further randomized into control (seven clusters) and intervention (seven clusters) for a two-armed cluster randomized controlled trial. Randomization was performed in R (version 3.5.2) using the randomizeR package (version 1.4.2.).

The number of houses targeted to participate in the study will be 50 houses per cluster. The field study will run for 50 weeks. All study participants will receive an insecticide-treated bednet recommended for use by the Tanzanian health authorities. Houses of the study participants that fall within the clusters selected for the 3D window double screen (3D-WDS) installations will receive some house improvements in the form of fitting mosquito nets (3D-WDS) on the windows of their houses. The households will be visited every 10 weeks for a total of five visits during the lifetime of the project to examine one or more children living in the house for malaria. Indoor mosquito densities will be also measured at the same intervals using CDC-light traps in 20 houses per cluster for one night (4 days of collection from 5 houses per night).
Intervention typeOther
Primary outcome measureMalaria prevalence measured using a rapid diagnostic test and thick blood smear at baseline, 10, 20, 30, 40 and 50 weeks
Secondary outcome measuresCurrent secondary outcome measures as of 11/09/2024:
1. Anemia prevalence determined by measuring hemoglobin level using the Hemocue device at baseline, 10, 20, 30, 40 and 50 weeks
2. Body temperature measured using an infrared thermometer at baseline, 10, 20, 30, 40 and 50 weeks
3. Bio-metrics (height, weight and MUAC) measured using a measuring tape and weight scale at baseline, 10, 20, 30, 40 and 50 weeks
4. Indoor mosquito density measured using CDC-light traps at baseline, 10, 20, 30, 40 and 50 weeks
5. Entomological inoculation rate measured using CDC-light traps and RT-PCR at baseline, 10, 20, 30, 40 and 50 weeks
6. Acceptability of intervention measured using focus group discussions and interviews starting from week 50 over 3 weeks



Previous secondary outcome measures:
1. Anemia prevalence is determined by measuring hemoglobin level using the Hemocue device at baseline, 10, 20, 30, 40 and 50 weeks
2. Body temperature is measured using an infrared thermometer at baseline, 10, 20, 30, 40 and 50 weeks
3. Bio-metrics (height, weight and MUAC) are measured using a measuring tape and weight scale at baseline, 10, 20, 30, 40 and 50 weeks
4. Indoor mosquito density is measured using CDC-light traps at baseline, 10, 20, 30, 40 and 50 weeks
5. Acceptability of intervention is measured using focus group discussions and interviews starting from week 50 over 3 weeks
Overall study start date29/05/2019
Completion date31/08/2021

Eligibility

Participant type(s)Mixed
Age groupMixed
SexBoth
Target number of participants7 intervention clusters; 50 households per cluster; malaria screening for 263 children. 7 control clusters; 50 households per cluster; malaria screening for 263 children
Key inclusion criteria1. Traditional Tanzanian village house with at least a single window or outlet which can accommodate the 3D-WDS and at least a single sleeping space
2. House made for long-term residential purposes (at least for the duration of the study)
3. At least one child aged 6 months - 14 years sleeping inside the house
4. Consent to
4.1. Install 3D-WDS in the house (intervention clusters only)
4.2. Use insecticide-treated nets (both intervention and control clusters) for a period of 12 months after the installation
4.3. Malaria screening for at least one child of the household
Key exclusion criteria1. Community houses with fixed window panels, shutters, or well-constructed aluminium panels with glass windows
2. Houses without a sleeping space i.e., made for the purpose of cooking and dining or cattle shed
3. Buildings that are temporarily constructed or made with the purpose to serve as a community hall, recreational centre, mosque or church
4. Households with no children aged 6 months to 14 years
5. Children without informed consent
6. Children with health conditions that require frequent hospital or health centre visits
Date of first enrolment01/10/2019
Date of final enrolment31/05/2021

Locations

Countries of recruitment

  • Tanzania

Study participating centre

National Institute of Medical Research
Amani Research Centre
Muheza
PO Box 81
Tanzania

Sponsor information

University of Helsinki
University/education

Department of Bacteriology and Immunology
Haartman Institute (Haartmaninkatu 3)
PO Box 21
Helsinki
00014
Finland

Phone +358 (0)505812462
Email seppo.meri@helsinki.fi
Website https://www.helsinki.fi/
ROR logo "ROR" https://ror.org/040af2s02

Funders

Funder type

Charity

Jane ja Aatos Erkon Säätiö
Private sector organisation / Trusts, charities, foundations (both public and private)
Alternative name(s)
Jane and Aatos Erkko Foundation, Jane och Aatos Erkkos stiftelse, J&AE
Location
Finland
Helsingin Yliopisto
Government organisation / Universities (academic only)
Alternative name(s)
University of Helsinki, Helsingfors Universitet, Universitas Helsingiensis, HY, UH
Location
Finland

Results and Publications

Intention to publish date01/07/2023
Individual participant data (IPD) Intention to shareNo
IPD sharing plan summaryData sharing statement to be made available at a later date
Publication and dissemination planPlanned publication in a high-impact peer reviewed journal
IPD sharing planThe data-sharing plans for the current study are unknown and will be made available at a later date

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
Protocol article 04/06/2025 25/06/2025 Yes No

Editorial Notes

25/06/2025: Publication reference added.
11/09/2024: Secondary outcome measures were updated.
27/10/2022: Trial's existence confirmed by the National Institute for Medical Research ethics committee and the Helsinki and Uusimaa Hospital District medical research ethics committee.