Last Updated: 07/03/2023

Impact of long-lasting insecticide treated bednets with and without PBO on malaria indicators in Uganda: a cluster randomised trial

Objectives

The main objective of this study is to evaluate the impact of combination LLINs (with PBO), as compared to conventional LLINs (without PBO), on parasite prevalence, in Eastern and Western Uganda. The specific objectives are:

To evaluate the impact of combination LLINs (with PBO), as compared to conventional LLINs (without PBO), on parasite prevalence;
To evaluate the impact of PermaNet 3.0 (with PBO), as compared to PermaNet 2.0 (without PBO), on parasite prevalence;
To evaluate the impact of Olyset Plus (with PBO), as compared to Olyset Net (without PBO), on parasite prevalence;
To determine factors associated with effectiveness of LLINs with PBO, as compared to LLINs without PBO, including the level of insecticide resistance; and
To assess net survivorship, durability, and bio-efficacy in Uganda. We will conduct cross-sectional surveys to determine net survivorship, attrition, and use, and will supplement these with laboratory assessments of net durability and bio-efficacy.

Principal Institution

Liverpool School of Tropical Medicine (LSTM), United Kingdom
Infectious Diseases Research Collaboration (IDRC), Uganda

Principal Investigators / Focal Persons

Janet Hemingway
Martin James Donnelly
Moses Robert Kamya
Sarah G. Staedke

Partner Institutions

Ministry of Health (MOH) Uganda
Makerere University, Uganda
London School of Hygiene and Tropical Medicine (LSHTM), United Kingdom
University of California San Francisco (UCSF), United States

Study Design

Intervention:

A universal LLIN distribution campaign will be led by the National Malaria Control Programme and partners. LLINs will be distributed at the level of cluster (HSD).

Evaluation Methodology:

1) Cross-sectional surveys. At baseline (prior to distributing LLINs), and up to 4 times after nets are distributed (at 6, 12, 18 and 24-30 months after distribution), randomly selected households will be surveyed from each of the clusters. The survey will include a household questionnaire and clinical & laboratory evaluation of children aged 2-10 years. We will survey 50 households in each cluster (n=5,200), aiming to recruit all eligible children in each household (approximately 10,400 children) per survey.
2) Entomology surveys. Mosquitoes from 5-10 randomly selected households in all 104 clusters using prokopack aspirators, aiming to collect 30-50 mosquitoes per cluster for genotypic monitoring. Mosquitoes will also be collected from 10-15 purposely selected households in 12 sentinel site clusters for phenotypic monitoring. Collections will be carried out concurrently with the cross-sectional surveys.
3) Insecticide resistance monitoring. Insecticide resistance will be measured using genotypic and phenotypic assays. Genotyping will be done on mosquitos collected from all 104 clusters. Mosquitoes species will be identified, and A. gambiae and A. arabiensis will be screened for key insecticide target sites (e.g. Vgsc) together with variants in metabolic resistance genes (e.g. Gste4, Cyp4j5, and Coeae1d). Phenotypic assays will be done on specimens from up to 12 sentinel sites, up to 6 per region, using permethrin, deltamethrin, permethrin + PBO and deltamethrin + PBO.
4) LLIN survivorship, durability and bio-efficacy. Information on net survivorship and use will be collected in the cross-sectional surveys. One year after distribution of nets, we will quantify net durability using the WHO Vector Control Working Group methodology, and will conduct standard WHO cone bioassays on 100 bar-coded nets collected from the community. Net durability assessments will be repeated at 24-30 months and 36-48 months, funding permitting.

Project Outputs