Repellents as Added Control Measure to Long Lasting Insecticidal Nets (MalaResT)

Repellents as Added Control Measure to Long Lasting Insecticidal Nets to Target the Residual Transmission in Southeast Asia: a Step Forwards to Malaria Elimination

The scaling up of Long Lasting Insecticidal Nets (LLIN) and the expansion of Indoor Residual Spraying (IRS) has contributed to a significant decrease of malaria worldwide. However these control methods tackle only indoor and night biting vectors. The proportion of transmission occurring outdoors and before sleeping hours or so-called "residual transmission" is steadily increasing and may compromise the effort towards malaria elimination.

The purpose of this study is to raise evidence on the effectiveness of mass use of topical repellents in addition to LLINs in controlling malaria infections.

A multidisciplinary approach will be used to collect information on the most important factors that contribute to the successful reduction of "residual malaria transmission". In a first objective the epidemiological efficacy of repellents on prevalence of malaria carriers and malaria incidence will be assessed. To achieve this goal 98 communities will be randomly assigned to one of two treatment arms (LLIN and LLIN + repellent). Within a community a cross sectional random sample of 65 people will be drawn at the beginning and the end of the malaria season to obtain an estimate of the malaria prevalence. The second objective will handle the entomological efficacy and persistence of the topical repellent on malaria vectors. And lastly the acceptability, adherence and adequacy of the topical repellents will be studied in a third objective.

Study Overview

• Status: Completed
• Conditions: Malaria
• Intervention / Treatment: Other: Mosquito topical repellent

• Study Type: Interventional
• Enrollment (Actual): 40000
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Cambodia
  • Ratanakiri
    • Ban Lŭng, Ratanakiri, Cambodia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 2 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• All household members volunteering from selected communities

Exclusion Criteria:

• Infants less than 2 years

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Topical Repellent & LLIN	Other: Mosquito topical repellent; Daily repellent use, before and after sleeping hours during the malaria season (6 months) in addition to the use of Long Lasting Insecticidal Nets during sleeping hours.; Other Names: Brand name: Autan; Active ingredient: Icaridin
No Intervention: Long Lasting Insecticidal Nets; Brand Name LLIN: Olyset Net Active ingredient: permethrin

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in malaria prevalence at 6 months	Malaria prevalence (PCR detection) will be measured in both study arms at the start and end of the malaria season for 2 consecutive years.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Malaria incidence	Through passive RDT case detection	6 months

Collaborators and Investigators

• Sponsor: Institute of Tropical Medicine, Belgium
• Collaborators: Institut Pasteur; NCHADS - Ministry of Health of Cambodia
• Investigators: Principal Investigator: Marc Coosemans, Professor, Institute Of Tropical Medicine Antwerp

Publications and helpful links

General Publications

• Canier L, Khim N, Kim S, Sluydts V, Heng S, Dourng D, Eam R, Chy S, Khean C, Loch K, Ken M, Lim H, Siv S, Tho S, Masse-Navette P, Gryseels C, Uk S, Van Roey K, Grietens KP, Sokny M, Thavrin B, Chuor CM, Deubel V, Durnez L, Coosemans M, Menard D. An innovative tool for moving malaria PCR detection of parasite reservoir into the field. Malar J. 2013 Nov 9;12:405. doi: 10.1186/1475-2875-12-405.
• Sluydts V, Durnez L, Heng S, Gryseels C, Canier L, Kim S, Van Roey K, Kerkhof K, Khim N, Mao S, Uk S, Sovannaroth S, Grietens KP, Sochantha T, Menard D, Coosemans M. Efficacy of topical mosquito repellent (picaridin) plus long-lasting insecticidal nets versus long-lasting insecticidal nets alone for control of malaria: a cluster randomised controlled trial. Lancet Infect Dis. 2016 Oct;16(10):1169-1177. doi: 10.1016/S1473-3099(16)30148-7. Epub 2016 Jun 29.
• Heng S, Durnez L, Gryseels C, Van Roey K, Mean V, Uk S, Siv S, Grietens KP, Sochantha T, Coosemans M, Sluydts V. Assuring access to topical mosquito repellents within an intensive distribution scheme: a case study in a remote province of Cambodia. Malar J. 2015 Nov 24;14:468. doi: 10.1186/s12936-015-0960-4.

Study record dates

Study Major Dates

• Study Start: May 1, 2012
• Primary Completion (Actual): December 1, 2013
• Study Completion (Actual): December 1, 2013

Study Registration Dates

• First Submitted: July 17, 2012
• First Submitted That Met QC Criteria: August 9, 2012
• First Posted (Estimated): August 13, 2012

Study Record Updates

• Last Update Posted (Actual): May 11, 2025
• Last Update Submitted That Met QC Criteria: May 9, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: Cambodia; Anopheles; Outdoor Malaria Transmission; Topical repellent; Early biting vector; Long Lasting Insecticidal Net (LLIN)
• Additional Relevant MeSH Terms: Vector Borne Diseases; Mosquito-Borne Diseases; Infections; Protozoan Infections; Parasitic Diseases; Malaria
• Other Study ID Numbers: OPP1032354