Elimination of onchocerciasis in Africa by 2025: the need for a broad perspective

Ed Cupp,Thomas R Unnasch,Vitaliano Cama,Mauricio Sauerbrey,Mark Eberhard,Patrick J Lammie

doi:10.1186/s40249-019-0557-1

Abstract

BackgroundIn response to the recent publication “Is onchocerciasis elimination in Africa feasible by 2025: a perspective based on lessons learnt from the African control programmes” by Dadzie et al., it is important to clarify and highlight the positive and unequivocal research and operational contributions from the American experience towards the worldwide elimination of human onchocerciasis (river blindness).Main textThe strategies of twice or more rounds of mass drug administration (MDA) of ivermectin per year, as well as the use of OV-16 serology have allowed four American countries to be verified by World Health Organization to have eliminated transmission of Onchocerca volvulus, the etiological agent. These advances were also implemented in Sudan and Uganda; currently, both are the only African countries where ivermectin MDA was safely stopped in several transmission zones.ConclusionsProgrammatic treatment and evaluation approaches, pioneered in the Americas, are the most efficient among the existing tools for elimination, and their broader use could catalyze the successful elimination of this disease in Africa.

Highlights

The strategies of twice or more rounds of mass drug administration (MDA) of ivermectin per year, as well as the use of OV-16 serology have allowed four American countries to be verified by World Health Organization to have eliminated transmission of Onchocerca volvulus, the etiological agent
The recent publication “Is onchocerciasis elimination in Africa feasible by 2025: a perspective based on lessons learnt from the African control programmes” by Dadzie et al [1] is quite informative in recounting the evolution of onchocerciasis control programs in Africa and the history behind the decision to move from control to elimination
The use of twice per year mass drug administration (MDA) of ivermectin Onchocerciasis Elimination Program for the Americas (OEPA) pioneered the use of twice per year treatments at high coverage rates, and in so doing has eliminated onchocerciasis from four of the six countries affected in the region; Colombia [5], Ecuador [6], Mexico [7] and Guatemala [8]

Summary

Main text

The use of twice per year mass drug administration (MDA) of ivermectin OEPA pioneered the use of twice per year treatments at high coverage rates, and in so doing has eliminated onchocerciasis from four of the six countries affected in the region; Colombia [5], Ecuador [6], Mexico [7] and Guatemala [8]. Epidemiological models Dadzie et al highlight the fact that APOC relied heavily on models to inform their strategy Both OCP and APOC worked closely with modelers to develop predictions for the effects of vector control and ivermectin MDA on the dynamics of infection in the human population and transmission of O. volvulus. The value of relying on models to make such strategic decisions is predicated on the underlying accuracy of the model predictions In this regard, it is disturbing that the two models developed with APOC and OCP support (EPIONCHO and ONCHOSIM) have produced predictions that varied widely in some operationally important areas, such as the risk of recrudescence of infection following cessation of annual ivermectin distribution in areas where vector biting rates are high [32]. The Mali/ Senegal report (which soon gave way to APOC elimination guidelines) made no mention of the official 2001 WHO published guidelines, and especially ignored the principle of monitoring infection in children as a measure of recent incidence

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