Modelling the Impact of Vector Control on Lymphatic Filariasis Programs: Current Approaches and Limitations.

E L Davis,J Prada,T D Hollingsworth,L J Reimer

doi:10.1093/cid/ciab191

E L Davis, J Prada + Show 2 more

Open Access

https://doi.org/10.1093/cid/ciab191

Copy DOI

Abstract

Vector control is widely considered an important tool for lymphatic filariasis (LF) elimination but is not usually included in program budgets and has often been secondary to other policy questions in modelling studies. Evidence from the field demonstrates that vector control can have a large impact on program outcomes and even halt transmission entirely, but implementation is expensive. Models of LF have the potential to inform where and when resources should be focused, but often simplify vector dynamics and focus on capturing human prevalence trends, making them comparatively ill-designed for direct analysis of vector control measures. We review the recent modelling literature and present additional results using a well-established model, highlighting areas of agreement between model predictions and field evidence, and discussing the possible determinants of existing disagreements. We conclude that there are likely to be long-term benefits of vector control, both on accelerating programs and preventing resurgence.

Highlights

Lymphatic filariasis (LF) is a filarial worm infection transmitted by mosquitoes that can lead to permanent and debilitating disability if left untreated
Almost 900 million people are at risk of infection worldwide and the disease has been targeted for elimination as a public health problem (EPHP) by 2030 by the World Health Organization (WHO) [1]
The WHO recommended strategy for reducing transmission of LF is a minimum of 5 years of annual mass drug administration (MDA) at 65% coverage in Nonstandard Abbreviations: AIBR, annual infective biting rate; DA, DeC and albendazole; DEC, diethylcarbamazine; IA, ivermectin and albendazole; EPHP, elimination as a public helath problem; GPELF, Global Programme to Eliminate Lymphatic Filariasis; IDA, ivermectin, DEC, and albendazole; IQR, interquartile range; IRS, indoor residual spraying; LF, lymphatic filariasis; LLINs, long-lasting insecticide-treated nets; MDA, mass drug administration; mf, male–female; PNG, Papua New Guinea; PVS, post-validation surveillance; WHO, World Health Organization

Summary

Introduction

Lymphatic filariasis (LF) is a filarial worm infection transmitted by mosquitoes that can lead to permanent and debilitating disability if left untreated. The WHO recommended strategy for reducing transmission of LF is a minimum of 5 years of annual mass drug administration (MDA) at 65% coverage in Nonstandard Abbreviations: AIBR, annual infective biting rate; DA, DeC and albendazole; DEC, diethylcarbamazine; IA, ivermectin and albendazole; EPHP, elimination as a public helath problem; GPELF, Global Programme to Eliminate Lymphatic Filariasis; IDA, ivermectin, DEC, and albendazole; IQR, interquartile range; IRS, indoor residual spraying; LF, lymphatic filariasis; LLINs, long-lasting insecticide-treated nets; MDA, mass drug administration; mf, male–female; PNG, Papua New Guinea; PVS, post-validation surveillance; WHO, World Health Organization. The breakpoint is the threshold prevalence at which the likelihood of sexual reproduction in a host drops sufficiently low that sustained transmission is no longer viable. This breakpoint depends on a number of factors, including the mosquito biting rate, and reductions in biting increase the breakpoint. We review the current field evidence and modelling literature on vector control usage for lymphatic filariasis control and elimination and discuss how modelling methods could be extended to more accurately capture vector dynamics

Methods

Results

Discussion

Conclusion