Dr Philip McCall
+44 (0)151 705 3132
A cluster randomised controlled trial of household-based insecticide-treated indoor curtains for control of the dengue vector Aedes aegypti and prevention of transmission of dengue in the community
We investigated whether window curtains made from long-lasting insecticide-treated netting and deployed inside houses, could reduce dengue virus transmission, as measured by seroconversion rates in humans, following reductions in dengue vector populations, as measured by a series of standard indices for Aedes aegypti intra-domiciliary and peri-domestic abundance, in intervention groups compared to control groups.
1. Research Ethics Committee of the Liverpool School of Tropical Medicine approved on 8th June 2009 (ref: 09/59)
2. Loreto Regional Health (Direccion Regional de Salud de Loreto), Peru approved on 3rd July 2009 (ref 586-2009-GRL-DRS/30.09.01)
3. US Naval Medical Research Center Detachment (NAMRID) Lima approved on 8th September 2009 (project no. 6000 RAD1.S.B0302; Approval ref. NAVMEDRSCHCENDETACHMENTINST 3900.6H)
Cluster randomised controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
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Dengue (including Dengue Haemorrhagic Fever [DHF] and Dengue Shock Syndrome [DSS])
Insecticide-treated curtains deployed inside human habitations. The curtains are made from PermaNet® deltamethrin-coated polyester netting, a long-lasting impregnated material (Vestergaard-Frandsen, Lausanne, Switzerland), that has been approved for indoor use (World Health Organisation Pesticide Evaluation Scheme [WHOPES]), with proven efficacy against dengue vectors.
Householders in treated clusters are permitted to dictate the quantity and location of their insecticide-treated materials (ITMs), with a minimum of one ITM required for the household to be classified as receiving treatment.
Control households received no treatment, but will be offered ITMs at the end of the study.
Efficacy of the intervention (Insecticide-treated curtains as described in E51) fell to an unacceptably low level (as determined by standard WHO recommended bioassays and other methods), when monitored over a period of months during 2010. Consequently, in October and November 2010, the existing curtains were treated again with a different product ("K-O Tab 1 2 3"; Bayer Environmental Science, Germany) designed to deliver a long-lasting formulation of the same insecticide.
Primary outcome measure
Effect of ITMs on dengue transmission - measured by detection of dengue specific antibodies in human blood, taken from householders within the study area, using the Plaque Reduction Neutralizing Antibody test (PRNT). PRNT is specific to dengue virus serotype, and is the gold standard against which all other dengue virus (DV) serological assays are validated.
Blood samples will be collected from the study population at baseline and at three 9-month intervals thereafter (9, 18, 24 months post intervention) in householders that were not positive for all four circulating serotypes during the immediate preceding survey.
Secondary outcome measures
1. The effect of ITMs on household vector infestation and breeding primarily measured by:
1.1 The adult index (proportion of houses positive for adult Ae. aegypti)
1.2. The Breteau index (number of containers with immature vector stages/100 houses)
Secondarily by the other Stegomyia indices:
1.3. Pupae per person index (number of pupae per number of people)
1.4. House index (percentage of houses found with immature stages of Ae. aegypti)
1.5. Container index (percentage of water-holding containers found with immature stages of Ae. aegypti).
Six surveys will be conducted: Baseline and 1, 6, 12, 18 and 24 months post intervention.
2. Quantification of spill-over effects from treated clusters on nearby control clusters, a potential confounding effect on analyses as well as an indicator of potential community-level impact
3. Determining factors associated with adoption and continued use of ITMs, including the most effective diffusion mechanism (channel of communication) for ITM promotion, by household questionnaires and focus group discussions. Surveys will coincide with the serological surveys.
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. All occupied households
1.1. Persons aged 3 years or older with parental permission
1.2. Adults consenting to participate in the study living in the study area
1.3. Assent to participation for 8-17 year old persons
Target number of participants
Estimated 9,200 participants from 1,400 households (based on 20 clusters of 70 houses/460 individual participants per cluster, 10 clusters per treatment arm)
Participant exclusion criteria
1. Persons younger than 3 years old
2. Temporary visitors to the study areas
3. Adults who do not consent to participate
4. 8-17 year old persons who do not assent or who do not have parental permission to participate in the study
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Liverpool School of Tropical Medicine (UK)
The Wellcome Trust (UK) (grant ref: 085714)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)