Identifying co-endemic areas for major filarial infections in sub-Saharan Africa: seeking synergies and preventing severe adverse events during mass drug administration campaigns
File(s)
Supporting information
Author(s)
Type
Journal Article
Abstract
BACKGROUND: Onchocerciasis and lymphatic filariasis (LF) are major filarial infections targeted for elimination in most endemic sub-Saharan Africa (SSA) countries by 2020/2025. The current control strategies are built upon community-directed mass administration of ivermectin (CDTI) for onchocerciasis, and ivermectin plus albendazole for LF, with evidence pointing towards the potential for novel drug regimens. When distributing microfilaricides however, considerable care is needed to minimise the risk of severe adverse events (SAEs) in areas that are co-endemic for onchocerciasis or LF and loiasis. This work aims to combine previously published predictive risk maps for onchocerciasis, LF and loiasis to (i) explore the scale of spatial heterogeneity in co-distributions, (ii) delineate target populations for different treatment strategies, and (iii) quantify populations at risk of SAEs across the continent. METHODS: Geographical co-endemicity of filarial infections prior to the implementation of large-scale mass treatment interventions was analysed by combining a contemporary LF endemicity map with predictive prevalence maps of onchocerciasis and loiasis. Potential treatment strategies were geographically delineated according to the level of co-endemicity and estimated transmission intensity. RESULTS: In total, an estimated 251 million people live in areas of LF and/or onchocerciasis transmission in SSA, based on 2015 population estimates. Of these, 96 million live in areas co-endemic for both LF and onchocerciasis, providing opportunities for integrated control programmes, and 83 million live in LF-monoendemic areas potentially targetable for the novel ivermectin-diethylcarbamazine-albendazole (IDA) triple therapy. Only 4% of the at-risk population live in areas co-endemic with high loiasis transmission, representing up to 1.2 million individuals at high risk of experiencing SAEs if treated with ivermectin. In these areas, alternative treatment strategies should be explored, including biannual albendazole monotherapy for LF (1.4 million individuals) and 'test-and-treat' strategies (8.7 million individuals) for onchocerciasis. CONCLUSIONS: These maps are intended to initiate discussion around the potential for tailored treatment strategies, and highlight populations at risk of SAEs. Further work is required to test and refine strategies in programmatic settings, providing the empirical evidence needed to guide efforts towards the 2020/2025 goals and beyond.
Date Issued
2018-01-31
Date Acceptance
2018-01-16
Citation
Parasites & Vectors, 2018, 11 (1), pp.70-70
ISSN
1756-3305
Publisher
BioMed Central
Start Page
70
End Page
70
Journal / Book Title
Parasites & Vectors
Volume
11
Issue
1
Copyright Statement
© The Author(s). 2018
Open Access
This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (
http://creativecommons.org/licenses/by/4.0/
), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/
) applies to the data made available in this article, unless otherwise stated.
Open Access
This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (
http://creativecommons.org/licenses/by/4.0/
), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/
) applies to the data made available in this article, unless otherwise stated.
Sponsor
Bill & Melinda Gates Foundation
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/29382363
PII: 10.1186/s13071-018-2655-5
Grant Number
WPIA_P65811
Subjects
Albendazole
DEC
Filariasis
GIS
Ivermectin
Loiasis
Lymphatic filariasis
Mapping
Onchocerciasis
Severe adverse events
Publication Status
Published online
Coverage Spatial
England