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Global Eradication of Lymphatic Filariasis: The Value Of Chronic Disease Control in Parasite Elimination Programs

Edwin Michael¹, Mwele N. Malecela², Mihail Zervos³ & James W. Kazura⁴

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1. Department of Infectious Disease Epidemiology, Imperial College
2. National Institute for Medical Research, Dar es Salaam, Tanzania
3. Mathematics Department, London School of Economics and Political Science
4. Center for Global Health and Diseases, Case Western Reserve University

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Document Type:

Manuscript

Date:

Received 02 February 2008 16:14 UTC; Posted 04 February 2008

Subjects:

Ecology

Tags:

• lymphatic filariasis
• disease eradication
• mathematical modeling
• parasite

Abstract:

The ultimate goal of the global programme against lymphatic filariasis is eradication through irrevocable cessation of transmission using 4 to 6 years of annual single dose mass drug administration. The costs of eradication, and logistical and managerial impediments to executing national and regional control programmes, and scientific uncertainty about transmission endpoints, are challenges to the success of this effort, especially in areas of high endemicity where financial resources are limited. We used a combined analysis of empirical community data describing the association between infection and chronic disease prevalence, mathematical modelling, and economic analyses to identify and evaluate the feasibility of setting an infection target level at which the chronic pathology attributable to lymphatic filariasis – lymphoedema of the extremities (elephantiasis) and hydroceles – becomes negligible in the face of continuing transmission as a first stage option in achieving the elimination of this parasitic disease. The results show that microfilaria prevalences below a threshold of 3.55% at a blood sampling volume of 1 ml could constitute readily achievable and sustainable targets to control disease due to lymphatic filariasis. They also show that as a result of the high marginal cost of curing the last few individuals to achieve elimination, maximal benefits can occur at the disease control threshold. Indeed, a key finding from our coupled economic and epidemiological analysis is that when initial uncertainty regarding eradication occurs and prospects for improving information to resolve such uncertainty over time exist, it is economically beneficial to adopt a flexible, sequential, eradication strategy based on controlling chronic disease initially. These results suggest that it may be optimal to set phased targets for the elimination of lymphatic filariasis, starting with disease control followed by intensified efforts to eradicate transmission as better knowledge regarding transmission dynamics and issues of implementation feasibility becomes evident. They also illustrate the importance of taking explicit accounts of uncertainties, multi-staged endpoints, and the value of embedding flexibility in the decision making process when determining optimal parasite eradication strategies.

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License:

This document is licensed to the public under the Creative Commons Attribution 3.0 License

How to cite this document:

Michael, Edwin, Malecela, Mwele, Zervos, Mihail, and Kazura, James. Global Eradication of Lymphatic Filariasis: The Value Of Chronic Disease Control in Parasite Elimination Programs. Available from Nature Precedings <http://hdl.handle.net/10101/npre.2008.1564.1> (2008)

Version info:

Published version:

10.1371/journal.pone.0002936 (Peer Reviewed) Published as: Michael E, Malecela MN, Zervos M, Kazura JW (2008) Global Eradication of Lymphatic Filariasis: The Value of Chronic Disease Control in Parasite Elimination Programmes. PLoS ONE 3(8): e2936.

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