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Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis
BACKGROUND: Diagnostics provide a means to measure progress toward disease elimination. Many countries in Africa are approaching elimination of onchocerciasis after successful implementation of mass drug administration programs as well as vector control. An understanding of how markers for infection...
Autores principales: | , , , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4907250/ https://www.ncbi.nlm.nih.gov/pubmed/27296630 http://dx.doi.org/10.1186/s13071-016-1623-1 |
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author | Golden, Allison Faulx, Dunia Kalnoky, Michael Stevens, Eric Yokobe, Lindsay Peck, Roger Karabou, Potochoziou Banla, Méba Rao, Ramakrishna Adade, Kangi Gantin, Richard G. Komlan, Kossi Soboslay, Peter T. de los Santos, Tala Domingo, Gonzalo J. |
author_facet | Golden, Allison Faulx, Dunia Kalnoky, Michael Stevens, Eric Yokobe, Lindsay Peck, Roger Karabou, Potochoziou Banla, Méba Rao, Ramakrishna Adade, Kangi Gantin, Richard G. Komlan, Kossi Soboslay, Peter T. de los Santos, Tala Domingo, Gonzalo J. |
author_sort | Golden, Allison |
collection | PubMed |
description | BACKGROUND: Diagnostics provide a means to measure progress toward disease elimination. Many countries in Africa are approaching elimination of onchocerciasis after successful implementation of mass drug administration programs as well as vector control. An understanding of how markers for infection such as skin snip microfilaria and Onchocerca volvulus-specific seroconversion perform in near-elimination settings informs how to best use these markers. METHODS: All-age participants from 35 villages in Togo were surveyed in 2013 and 2014 for skin snip Onchocerca volvulus microfilaria and IgG4 antibody response by enzyme-linked immunosorbent assay (ELISA) to the Onchocerca volvulus-specific antigen Ov16. A Gaussian mixture model applying the expectation-maximization (EM) algorithm was used to determine seropositivity from Ov16 ELISA data. For a subset of participants (n = 434), polymerase chain reaction (PCR) was performed on the skin snips taken during surveillance. RESULTS: Within the 2,005 participants for which there was Ov16 ELISA data, O. volvulus microfilaremia prevalence and Ov16 seroprevalence were, 2.5 and 19.7 %, respectively, in the total population, and 1.6 and 3.6 % in children under 11. In the subset of 434 specimens for which ELISA, PCR, and microscopy data were generated, it was found that in children under 11 years of age, the anti-Ov16 IgG4 antibody response demonstrate a sensitivity and specificity of 80 and 97 %, respectively, against active infections as determined by combined PCR and microscopy on skin snips. Further analysis was performed in 34 of the 35 villages surveyed. These villages were stratified by all-age seroprevalence into three clusters: < 15 %; 15–20 %; and > 20 %. Age-dependence of seroprevalence for each cluster was best reflected by a two-phase force-of-infection (FOI) catalytic model. In all clusters, the lower of the two phases of FOI was associated with a younger age group, as reflected by the seroconversion rates for each phase. The age at which transition from lower to higher seroconversion, between the two phases of FOI, was found to be highest (older) for the cluster of villages with < 15 % seroprevalence and lowest (younger) for the cluster with the highest all-age seroprevalence. CONCLUSIONS: The anti-Ov16 IgG4 antibody response is an accurate marker for active infection in children under 11 years of age in this population. Applying Ov16 surveillance to a broader age range provides additional valuable information for understanding progression toward elimination and can inform where targeted augmented interventions may be needed. Clustering of villages by all-age sero-surveillance allowed application of a biphasic FOI model to differentiate seroconversion rates for different age groups within the village cluster categories. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1623-1) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-4907250 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-49072502016-06-15 Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis Golden, Allison Faulx, Dunia Kalnoky, Michael Stevens, Eric Yokobe, Lindsay Peck, Roger Karabou, Potochoziou Banla, Méba Rao, Ramakrishna Adade, Kangi Gantin, Richard G. Komlan, Kossi Soboslay, Peter T. de los Santos, Tala Domingo, Gonzalo J. Parasit Vectors Research BACKGROUND: Diagnostics provide a means to measure progress toward disease elimination. Many countries in Africa are approaching elimination of onchocerciasis after successful implementation of mass drug administration programs as well as vector control. An understanding of how markers for infection such as skin snip microfilaria and Onchocerca volvulus-specific seroconversion perform in near-elimination settings informs how to best use these markers. METHODS: All-age participants from 35 villages in Togo were surveyed in 2013 and 2014 for skin snip Onchocerca volvulus microfilaria and IgG4 antibody response by enzyme-linked immunosorbent assay (ELISA) to the Onchocerca volvulus-specific antigen Ov16. A Gaussian mixture model applying the expectation-maximization (EM) algorithm was used to determine seropositivity from Ov16 ELISA data. For a subset of participants (n = 434), polymerase chain reaction (PCR) was performed on the skin snips taken during surveillance. RESULTS: Within the 2,005 participants for which there was Ov16 ELISA data, O. volvulus microfilaremia prevalence and Ov16 seroprevalence were, 2.5 and 19.7 %, respectively, in the total population, and 1.6 and 3.6 % in children under 11. In the subset of 434 specimens for which ELISA, PCR, and microscopy data were generated, it was found that in children under 11 years of age, the anti-Ov16 IgG4 antibody response demonstrate a sensitivity and specificity of 80 and 97 %, respectively, against active infections as determined by combined PCR and microscopy on skin snips. Further analysis was performed in 34 of the 35 villages surveyed. These villages were stratified by all-age seroprevalence into three clusters: < 15 %; 15–20 %; and > 20 %. Age-dependence of seroprevalence for each cluster was best reflected by a two-phase force-of-infection (FOI) catalytic model. In all clusters, the lower of the two phases of FOI was associated with a younger age group, as reflected by the seroconversion rates for each phase. The age at which transition from lower to higher seroconversion, between the two phases of FOI, was found to be highest (older) for the cluster of villages with < 15 % seroprevalence and lowest (younger) for the cluster with the highest all-age seroprevalence. CONCLUSIONS: The anti-Ov16 IgG4 antibody response is an accurate marker for active infection in children under 11 years of age in this population. Applying Ov16 surveillance to a broader age range provides additional valuable information for understanding progression toward elimination and can inform where targeted augmented interventions may be needed. Clustering of villages by all-age sero-surveillance allowed application of a biphasic FOI model to differentiate seroconversion rates for different age groups within the village cluster categories. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1623-1) contains supplementary material, which is available to authorized users. BioMed Central 2016-06-13 /pmc/articles/PMC4907250/ /pubmed/27296630 http://dx.doi.org/10.1186/s13071-016-1623-1 Text en © The Author(s). 2016 Open AccessThis 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. |
spellingShingle | Research Golden, Allison Faulx, Dunia Kalnoky, Michael Stevens, Eric Yokobe, Lindsay Peck, Roger Karabou, Potochoziou Banla, Méba Rao, Ramakrishna Adade, Kangi Gantin, Richard G. Komlan, Kossi Soboslay, Peter T. de los Santos, Tala Domingo, Gonzalo J. Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis |
title | Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis |
title_full | Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis |
title_fullStr | Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis |
title_full_unstemmed | Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis |
title_short | Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis |
title_sort | analysis of age-dependent trends in ov16 igg4 seroprevalence to onchocerciasis |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4907250/ https://www.ncbi.nlm.nih.gov/pubmed/27296630 http://dx.doi.org/10.1186/s13071-016-1623-1 |
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