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Elimination of onchocerciasis in Ecuador: findings of post-treatment surveillance.

Guevara, Á; Lovato, R; Proaño, R; Rodriguez-Perez, MA; Unnasch, T; Cooper, PJ; Guderian, RH (2018) Elimination of onchocerciasis in Ecuador: findings of post-treatment surveillance. Parasit Vectors, 11. p. 265. ISSN 1756-3305 https://doi.org/10.1186/s13071-018-2851-3
SGUL Authors: Cooper, Philip John

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Abstract

BACKGROUND: The Esmeraldas focus of onchocerciasis in Ecuador expanded geographically during the 1980s and was associated with severe ocular and skin disease. Mass drug administration (MDA) with ivermectin started in 1991, initially once but later twice a year, in the principle endemic focus followed by all satellite foci. Treatment was stopped in 2009 when entomological assessments determined that transmission of Onchocerca volvulus had been interrupted. METHODS: Three years after the cessation of ivermectin treatment in 2012, as defined by the WHO guidelines for onchocerciasis elimination, blackfly collections were done in four sentinel sites in former hyperendemic areas. The presence of infective larvae in local vectors, Simulium exiguum and Simulum quadrivittatum, was assessed by detection of O. volvulus DNA by PCR. Additional flies captured in four extra-sentinel sites located in former hyper- and mesoendemic dispersed isolated areas were also assessed. RESULTS: The results from 68,310 captured blackflies, 40,114 from four sentinel villages in the previously hyperendemic areas (Corriente Grande, El Tigre, San Miguel on Río Cayapas and Naranjal on Río Canandé) and 28,197 from extra-sentinel locations, were all negative for the presence of O. volvulus. These extra-sentinel sites (Hualpí on Río Hoja Blanca, Capulí on Río Onzole, La Ceiba on Río Tululví and Medianía on Río Verde) were included to provide additional evidence of the impact of MDA on the transmission of O. volvulus in isolated endemic areas. CONCLUSIONS: Our data indicate that transmission of O. volvulus has been stopped in all endemic areas in Ecuador, including all satellite foci outside the main focus. These findings indicate that a strategy of ivermectin distribution twice a year to over 85% of the treatment-eligible population was effective in eliminating the infection from Ecuador in a focus with a highly competent primary vector, S. exiguum, and where the infection rates were equal to or greater than observed in many onchocerciasis foci in Africa.

Item Type: Article
Additional Information: © 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.
Keywords: Ecuador, Elimination, Onchocerciasis, Transmission, Mycology & Parasitology, 1108 Medical Microbiology, 1117 Public Health And Health Services
SGUL Research Institute / Research Centre: Academic Structure > Infection and Immunity Research Institute (INII)
Journal or Publication Title: Parasit Vectors
ISSN: 1756-3305
Language: eng
Dates:
DateEvent
24 April 2018Published
16 April 2018Accepted
Publisher License: Creative Commons: Attribution 4.0
PubMed ID: 29690907
Go to PubMed abstract
URI: https://openaccess.sgul.ac.uk/id/eprint/109796
Publisher's version: https://doi.org/10.1186/s13071-018-2851-3

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