How can onchocerciasis elimination in Africa be accelerated? Modelling the impact of increased ivermectin treatment frequency and complementary vector control
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Background:
Great strides have been made toward onchocerciasis elimination by mass drug administration (MDA) of ivermectin. Focusing on MDA-eligible areas, we investigated where the elimination goal can be achieved by 2025 by continuation of current practice (annual MDA with ivermectin) and where intensification or additional vector control is required. We did not consider areas hypoendemic for onchocerciasis with loiasis coendemicity where MDA is contraindicated.
Methods:
We used 2 previously published mathematical models, ONCHOSIM and EPIONCHO, to simulate future trends in microfilarial prevalence for 80 different settings (defined by precontrol endemicity and past MDA frequency and coverage) under different future treatment scenarios (annual, biannual, or quarterly MDA with different treatment coverage through 2025, with or without vector control strategies), assessing for each strategy whether it eventually leads to elimination.
Results:
Areas with 40%–50% precontrol microfilarial prevalence and ≥10 years of annual MDA may achieve elimination with a further 7 years of annual MDA, if not achieved already, according to both models. For most areas with 70%–80% precontrol prevalence, ONCHOSIM predicts that either annual or biannual MDA is sufficient to achieve elimination by 2025, whereas EPIONCHO predicts that elimination will not be achieved even with complementary vector control.
Conclusions:
Whether elimination will be reached by 2025 depends on precontrol endemicity, control history, and strategies chosen from now until 2025. Biannual or quarterly MDA will accelerate progress toward elimination but cannot guarantee it by 2025 in high-endemicity areas. Long-term concomitant MDA and vector control for high-endemicity areas might be useful.
Great strides have been made toward onchocerciasis elimination by mass drug administration (MDA) of ivermectin. Focusing on MDA-eligible areas, we investigated where the elimination goal can be achieved by 2025 by continuation of current practice (annual MDA with ivermectin) and where intensification or additional vector control is required. We did not consider areas hypoendemic for onchocerciasis with loiasis coendemicity where MDA is contraindicated.
Methods:
We used 2 previously published mathematical models, ONCHOSIM and EPIONCHO, to simulate future trends in microfilarial prevalence for 80 different settings (defined by precontrol endemicity and past MDA frequency and coverage) under different future treatment scenarios (annual, biannual, or quarterly MDA with different treatment coverage through 2025, with or without vector control strategies), assessing for each strategy whether it eventually leads to elimination.
Results:
Areas with 40%–50% precontrol microfilarial prevalence and ≥10 years of annual MDA may achieve elimination with a further 7 years of annual MDA, if not achieved already, according to both models. For most areas with 70%–80% precontrol prevalence, ONCHOSIM predicts that either annual or biannual MDA is sufficient to achieve elimination by 2025, whereas EPIONCHO predicts that elimination will not be achieved even with complementary vector control.
Conclusions:
Whether elimination will be reached by 2025 depends on precontrol endemicity, control history, and strategies chosen from now until 2025. Biannual or quarterly MDA will accelerate progress toward elimination but cannot guarantee it by 2025 in high-endemicity areas. Long-term concomitant MDA and vector control for high-endemicity areas might be useful.
Date Issued
2018-06-01
Date Acceptance
2017-12-28
Citation
Clinical Infectious Diseases, 2018, 66 (Suppl. 4), pp.S267-S274
ISSN
1058-4838
Publisher
Oxford University Press (OUP)
Start Page
S267
End Page
S274
Journal / Book Title
Clinical Infectious Diseases
Volume
66
Issue
Suppl. 4
Copyright Statement
© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society
of America. This is an Open Access article distributed under the terms of the Creative Commons
Attribution 3.0 IGO (CC BY 3.0 IGO) License (https://creativecommons.org/licenses/by/3.0/igo/)
which permits unrestricted reuse, distribution, and reproduction in any medium, provided the
original work is properly cited.
of America. This is an Open Access article distributed under the terms of the Creative Commons
Attribution 3.0 IGO (CC BY 3.0 IGO) License (https://creativecommons.org/licenses/by/3.0/igo/)
which permits unrestricted reuse, distribution, and reproduction in any medium, provided the
original work is properly cited.
Sponsor
The Task Force for Global Health
Grant Number
MA4501180169
Subjects
Science & Technology
Life Sciences & Biomedicine
Immunology
Infectious Diseases
Microbiology
onchocerciasis
modeling
mass drug administration
ivermectin
elimination
RIVER-BLINDNESS
ECONOMIC-EVALUATION
CONTROL PROGRAM
WEST-AFRICA
TRANSMISSION
EFFICACY
VOLVULUS
06 Biological Sciences
11 Medical And Health Sciences
Publication Status
Published