Impact of Insecticide Resistance on Vector Control

Phase 4

• Conditions: Malaria, Falciparum

• Registration Number: NCT01713517
• Lead Sponsor: London School of Hygiene and Tropical Medicine

Brief Summary

The purpose of the study is to determine whether long lasting insecticidal nets and indoor residual insecticide spraying, alone or in combination, are effective for controlling insecticide resistant anopheles mosquitoes for malaria prevention.

Detailed Description

The study will assess the impact that insecticide resistance has on the effectiveness of malaria vector control tools LLIN and IRS. This is done by a cluster randomised trials of universal coverage LLINs versus universal coverage LLINs in combination with IRS, with levels of baseline insecticide resistance in the main vector balanced between the two study arms. In each cluster resistance to the insecticide used on LLINs is monitored, and malaria incidence is estimated from cluster specific cohorts of children followed up over the duration of the study. Resistance impact will be assessed from the ratio of incidence rates in clusters with high compared to those with low resistance and from a continuous measure of resistance expressed as percentage loss of mosquito mortality when exposed to insecticide in standardised WHO tests. Resistance mechanisms will be studied in subsets of study clusters.

Study Timeline

• Study Start: 2011-04
• Status Verified: 2012-10
• Study First Submitted: 2012-10-22
• Study First Submitted QC: 2012-10-22
• Study First Posted: 2012-10-24
• Last Update Submitted: 2012-10-25
• Last Update Posted: 2012-10-26
• Primary Completion: 2014-10
• Study Completion: 2014-10

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 28000

Inclusion Criteria

• Children older than 6 months and younger than 10 years in approximately 100 randomly selected households in all 140 study clusters selected in the four study areas

Exclusion Criteria

• Children living in households within 1 km from the edge of a neighbouring cluster (the buffer zone)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Malaria Incidence	3 years	Infection with malarial parasites determined by rapid diagnostic tests/microscopy in cohort members who report or have fever (\>37.5C)

Secondary Outcome Measures

Name	Time	Method
Prevalence of P.falciparum Infection	3 years	Infection with plasmodial parasites (falciparum and/or vivax) in randomly selected members of the study cohort in each study cluster during the peak of the malaria transmission season by rapid diagnostic test
Entomological Innoculation rate	Average for months Sept, Oct, Nov for years 2011, 2012, 2013	Anopheles arabiensis mosquitoes collected in sentinel clusters by light trap, window trap, clay pot and pyrethrum sheet collection and determination of sporozoite, human blood index, feeding and resting behaviour.
Frequency of insecticide resistance associated genotypes (kdr) in anopheles arabiensis	Yearly average 2011, 2012, 2013, 2014	Molecular analysis of mosquito specimens caught in subset of clusters by pyrethrum spray collection.

Trial Locations

Locations (1)

Malaria Control Programme; 🇸🇩 Kassala, Kassala State, Sudan