ITENs: Evaluation of Insecticide-treated Eave Nets and Window Screens for Malaria Control in Tanzania.
Study Details
Study Description
Brief Summary
This is a household randomized trial of a new tool for house modification, Insecticide-Treated Eave nets (ITENs) in combination with insecticide-treated window screens (ITWS), coated with a dual active ingredient (dual AI): Deltamethrin at 3g AI/kg, which corresponds to 144 mg/m² and PBO synergist at 10g/kg which corresponds to 480 mg/m², as used in the so-called dual-AI LLIN or "resistance breaking" nets for resistance malaria vector control.
Four hundred and fifty (450) households with intact walls, opened eaves, and those without screens or nets on the windows in Chalinze district, Tanzania will be eligible and only recruited upon written informed consent. The households will be randomly allocated into two arms: one with ITENs and ITWS installed and the other without.
The primary outcome will be malaria parasite detection in household residents aged over 6 months old using a quantitative Polymerase Chain Reaction (qPCR) at approximately 12 months post-installation, coinciding with the long rainy season.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
N/A |
Detailed Description
In Tanzania, long-lasting insecticidal nets (LLINs) contributed to the high reduction of malaria in the last decade. However, malaria reduction in Tanzania is threatened due to increasing insecticidal resistance of malaria vectors, low access to LLIN, LLINs not lasting up to three years, and net usage compliance. Therefore, it is evident that an additional cost-effective vector control tool is required that may confer protection against resistant malaria vectors, protect every member of the household, requires little or less compliance to use after distribution, and lasts longer.
The proposed additional vector control tool for trial is the Insecticide-Treated Eave nets (ITENs) in combination with Insecticide Treated Window screens (ITWS) for house modification. The tool is coated with a dual active ingredient (dual AI): Deltamethrin at 3g AI/kg, which corresponds to 144 mg/m², and PBO synergist at 10g/kg which corresponds to 480 mg/m², which are coated at the same concentration in insecticide-treated nets that are already in use in the population to control pyrethroid-resistant mosquitoes. These can protect everyone in the house by blocking mosquito entry and killing mosquitos that contact them to protect everyone in the community.
In this trial, 450 households will be randomly allocated into two arms. One arm with ITENs & ITWS installed and the other without to serve as the control arm. The 450 households are recruited and assigned codes during baseline data collection. The assigned codes are randomized to either of the two arms by simple randomization in STATA and stratified by sub-village.
Approximately 6 months and 12 months post-installation, coinciding with the rainy seasons, clinical officers will screen for malaria parasites in household residents of over 6 months old (it is estimated that 4.4 persons reside in each household, thus approx. 1,800 persons will be screened for malaria per survey) in both arms and confirmation of malaria parasite will be done using qPCR analysis as the primary assessment of the primary outcome. As a point of care, SD Bioline Malaria Ag Pf/Pan rapid diagnostic test (RDT) as per Tanzanian guidelines will also be conducted on all household residents. Any participant (s) with an axillary temperature of 37.5 degrees (fever) and that test positive using mRDT will be considered as a clinical malaria case. All malaria-positive participants will be treated using free Artemether Lumefantrine (ALu). This drug is approved by the national guideline for the treatment of uncomplicated malaria.
Other secondary objectives are:
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To evaluate malaria prevalence in households with ITENs & ITWS and those without at approximately 6 months post-installation, coinciding with the short rainy season.
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To determine the prevalence of clinical malaria defined by an axillary temperature of 37.5 degrees and above (fever) and mRDT malaria positive cases at approximately 6 months and 12 months post-installation, coinciding with the rainy seasons.
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To investigate the effect of ITENs and ITWS on the density of malaria vectors and nuisance (Culex quinquefasciatus) mosquitoes in the community at approximately 6 months and 12 months post-installation, coinciding with the rainy seasons using Centres for Disease Control (CDC) light traps.
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To assess the number of fabric in meters and time of installing the intervention (feasibility of scaling-up ITENs and ITWS use) in local houses in the field during installation.
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To assess the adverse effects of ITENs and ITWS in the community.
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To determine the attrition and fabric integrity of ITENs and ITWS in the field post 6 months and 12 months of installation.
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To determine the mortality induced by (bioefficacy) ITENs and ITWS on laboratory-reared mosquitoes post 12 months of installation.
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To determine the insecticide retainment of ITENs and ITWS post 12 months of installation.
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To assess the acceptability of ITENs and ITWS to the local community post 6 months and 12 months of installation.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: ITENs + ITWS Deltamethrin at 3g AI/kg, which corresponds to 144 mg/m², and PBO synergist at 10g/kg which corresponds to 480 mg/m² are coated in ITENs and ITWS nets that will be installed to cover opened eaves and windows. This was manufactured by Moon Netting FZCO, United Arab Emirates. |
Other: ITENs + ITWS
A dual active ingredient (dual AI) Insecticide-Treated Eave nets (ITENs) in combination with Insecticide Treated Window screens (ITWS) for house modification.
|
| No Intervention: Negative arm The houses allocated NOT to receive ITENs and ITWS. |
Outcome Measures
Primary Outcome Measures
- Prevalence of Plasmodium falciparum parasite. [Approximately 12 months post-installation, coinciding with the long rainy season.]
Prevalence of plasmodium falciparum parasite measured by qPCR among residents over 6 months old in houses with ITENs & ITWS compared to houses without.
Secondary Outcome Measures
- Prevalence of Plasmodium falciparum parasite. [Approximately 6 months post-installation, coinciding with the short rainy season.]
Prevalence of plasmodium falciparum parasite in households' residents of over 6 months old with ITENs & ITWS compared to those without using qPCR analysis.
- Clinical malaria. [Approximately 6 months and 12 months post-installation, coinciding with the rainy seasons.]
The prevalence of clinical malaria cases defined by an axillary temperature of 37.5 degrees (fever) and positive mRDT in houses with ITENs and ITWS compared to the houses without.
- The density of malaria vectors and nuisance mosquitoes density. [Approximately 6 months and 12 months post-installation, coinciding with the rainy seasons.]
Indoor density of malaria vector and nuisance mosquitoes in houses with ITENs & ITWS compared to houses without measured using Centres for Disease Control (CDC) light traps.
- ITENs & ITWS fabric cost [Baseline (During installation of ITENs & ITWS)]
The number of metres of material applied to houses.
- ITENS & ITWS time duration [Baseline (During installation of ITENs & ITWS)]
Time in hours to install the intervention.
- Adverse effects [Approximately one month post installation.]
The number of participants with perceived adverse effects from ITENs and ITWS.
- Attrition [Appriximately 6 months and 12 months post installation.]
Determination of the physical presence of ITENs and ITWS in the field.
- Fabric integrity [Appriximately 6 months and 12 months post installation.]
Determination of the number of holes in ITENs and ITWS in the field.
- The induced mosquito mortality of ITENs and ITWs on the population of laboratory-reared mosquitoes. [Approximately 12 months post installation.]
The bioefficacy (% induced mosquito mortality) of ITENs and ITWS after field use through WHO bioassays.
- Insecticide retainment [Appriximately 12 months post installation.]
The retention of deltamethrin and PBO in grams per kg will be assessed through high performance liquid chromatography.
- Use of ITENs and ITWS [Approximately 6 months and 12 months post installation.]
Community opinions of ITENs and ITWS will be sought through questionnaires and Focus Group Discussions.
Eligibility Criteria
Criteria
Inclusion Criteria:
- Residents of study households' members.
Exclusion Criteria:
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None residence.
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Pregnant women.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Vector Control Product Testing Unit Facility | Bagamoyo | Tanzania |
Sponsors and Collaborators
- Ifakara Health Institute
- London School of Hygiene and Tropical Medicine
- Swiss Tropical & Public Health Institute
Investigators
- Study Director: John Bradley, PhD, London School of Hygiene and Tropical Medicine
Study Documents (Full-Text)
More Information
Publications
- Gnanguenon V, Azondekon R, Oke-Agbo F, Beach R, Akogbeto M. Durability assessment results suggest a serviceable life of two, rather than three, years for the current long-lasting insecticidal (mosquito) net (LLIN) intervention in Benin. BMC Infect Dis. 2014 Feb 8;14:69. doi: 10.1186/1471-2334-14-69.
- Matiya DJ, Philbert AB, Kidima W, Matowo JJ. Dynamics and monitoring of insecticide resistance in malaria vectors across mainland Tanzania from 1997 to 2017: a systematic review. Malar J. 2019 Mar 26;18(1):102. doi: 10.1186/s12936-019-2738-6.
- Mboera LE, Mweya CN, Rumisha SF, Tungu PK, Stanley G, Makange MR, Misinzo G, De Nardo P, Vairo F, Oriyo NM. The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014. PLoS Negl Trop Dis. 2016 Jan 26;10(1):e0004313. doi: 10.1371/journal.pntd.0004313. eCollection 2016 Jan.
- Mboma ZM, Overgaard HJ, Moore S, Bradley J, Moore J, Massue DJ, Kramer K, Lines J, Lorenz LM. Mosquito net coverage in years between mass distributions: a case study of Tanzania, 2013. Malar J. 2018 Mar 1;17(1):100. doi: 10.1186/s12936-018-2247-z.
- ITENs