Investigating mosquito net durability for malaria control in Tanzania - attrition, bioefficacy, chemistry, degradation and insecticide resistance (ABCDR): study protocol.

Lena M Lorenz,Renata Mandike,William Kisinza,John Bradley,Jason D Moore,Dennis J Massue,Karen Kramer,Hans J Overgaard,Sarah J Moore,Zawadi D Mageni

doi:10.1186/1471-2458-14-1266

Abstract

BackgroundLong-Lasting Insecticidal Nets (LLINs) are one of the major malaria vector control tools, with most countries adopting free or subsidised universal coverage campaigns of populations at-risk from malaria. It is essential to understand LLIN durability so that public health policy makers can select the most cost effective nets that last for the longest time, and estimate the optimal timing of repeated distribution campaigns. However, there is limited knowledge from few countries of the durability of LLINs under user conditions.Methods/DesignThis study investigates LLIN durability in eight districts of Tanzania, selected for their demographic, geographic and ecological representativeness of the country as a whole. We use a two-stage approach: First, LLINs from recent national net campaigns will be evaluated retrospectively in 3,420 households. Those households will receive one of three leading LLIN products at random (Olyset®, PermaNet®2.0 or Netprotect®) and will be followed up for three years in a prospective study to compare their performance under user conditions. LLIN durability will be evaluated by measuring Attrition (the rate at which nets are discarded by households), Bioefficacy (the insecticidal efficacy of the nets measured by knock-down and mortality of mosquitoes), Chemical content (g/kg of insecticide available in net fibres) and physical Degradation (size and location of holes). In addition, we will extend the current national mosquito insecticide Resistance monitoring program to additional districts and use these data sets to provide GIS maps for use in health surveillance and decision making by the National Malaria Control Program (NMCP).DiscussionThe data will be of importance to policy makers and vector control specialists both in Tanzania and the SSA region to inform best practice for the maintenance of high and cost-effective coverage and to maximise current health gains in malaria control.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2458-14-1266) contains supplementary material, which is available to authorized users.

Highlights

Long-Lasting Insecticidal Nets (LLINs) are one of the major malaria vector control tools, with most countries adopting free or subsidised universal coverage campaigns of populations at-risk from malaria
The recent successes in malaria control in sub-Saharan Africa (SSA), in Tanzania where malaria deaths have reduced by 70% since 2003, has been largely attributable to the massive scale up of vector control tools, Long Lasting Insecticidal Nets (LLINs) [1,2,3]
In addition to following World Health Organization (WHO) durability guidelines [5], which will allow direct comparison between our study and other ongoing durability investigations in SSA, we are developing new methodologies to fully assess to what extent physical degradation, chemical decay and biological efficacy determine the life of a net, i.e. the duration of its effective protection

Summary

Introduction

Long-Lasting Insecticidal Nets (LLINs) are one of the major malaria vector control tools, with most countries adopting free or subsidised universal coverage campaigns of populations at-risk from malaria. It is essential to understand LLIN durability so that public health policy makers can select the most cost effective nets that last for the longest time, and estimate the optimal timing of repeated distribution campaigns. The recent successes in malaria control in sub-Saharan Africa (SSA), in Tanzania where malaria deaths have reduced by 70% since 2003, has been largely attributable to the massive scale up of vector control tools, Long Lasting Insecticidal Nets (LLINs) [1,2,3]. The deliveries of life-saving control tools will slow down and risk the reversal of the huge achievements to date. Maximising the impact of interventions through selection of the most cost effective and long lasting interventions is a health policy priority

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