Spatiotemporal distribution and population at risk of soil-transmitted helminth infections following an eight-year school-based deworming programme in Burundi, 2007-2014
Author(s)
Type
Journal Article
Abstract
Background: Investigating the effect of successive annual deworming rounds on the spatiotemporal distribution of
infection prevalence and numbers at risk for soil-transmitted helminths (STHs) can help identify communities
nearing elimination and those needing further interventions. In this study, we aim to quantify the impact of
an 8-year mass drug administration (MDA) programme (from 2007 to 2014) on the spatiotemporal distribution of
prevalence of STH infections and to estimate the number of school-aged children infected with STHs in Burundi.
Methods: During annual longitudinal school-based surveys in Burundi between 2007 and 2011, STH infection and
anthropometric data for a total of 40,656 children were collected; these data were supplemented with data from
a national survey conducted in 2014. Bayesian model based geostatistics (MBG) were used to generate predictive
prevalence maps for each STH species and year. The numbers of children at-risk of infection per district between
2008 and 2014 were estimated as the product of the predictive prevalence maps and population density maps.
Results: Overall, the degree of spatial clustering of STH infections decreased between 2008 and 2011; in 2014 the
geographical clusters of all STH infections reappeared. The reduction in prevalence was small for Ascaris lumbricoides
and Trichuris trichiura in the centre and central north of the country. Our predictive prevalence maps for hookworm
indicate a reduction in prevalence along the periphery of the country. The predicted number of children infected with
any STH species decreased substantially between 2007 and 2011, but in 2014 there was an increase in the predicted
number of children infected with A. lumbricoides and T. trichiura. In 2014, the districts with the highest predicted
number of children infected with A. lumbricoides, T. trichiura and hookworms were Kibuye district (n = 128,903),
Mabayi district (n = 35,302) and Kiremba (n = 87,511), respectively.
Conclusions: While the MDA programme in Burundi resulted in a reduction in STH prevalence, this reduction
was spatiotemporally heterogeneous, with some pockets of high prevalence remaining, suggesting that treatment
coverage and complementary interventions should be evaluated to improve impact.
infection prevalence and numbers at risk for soil-transmitted helminths (STHs) can help identify communities
nearing elimination and those needing further interventions. In this study, we aim to quantify the impact of
an 8-year mass drug administration (MDA) programme (from 2007 to 2014) on the spatiotemporal distribution of
prevalence of STH infections and to estimate the number of school-aged children infected with STHs in Burundi.
Methods: During annual longitudinal school-based surveys in Burundi between 2007 and 2011, STH infection and
anthropometric data for a total of 40,656 children were collected; these data were supplemented with data from
a national survey conducted in 2014. Bayesian model based geostatistics (MBG) were used to generate predictive
prevalence maps for each STH species and year. The numbers of children at-risk of infection per district between
2008 and 2014 were estimated as the product of the predictive prevalence maps and population density maps.
Results: Overall, the degree of spatial clustering of STH infections decreased between 2008 and 2011; in 2014 the
geographical clusters of all STH infections reappeared. The reduction in prevalence was small for Ascaris lumbricoides
and Trichuris trichiura in the centre and central north of the country. Our predictive prevalence maps for hookworm
indicate a reduction in prevalence along the periphery of the country. The predicted number of children infected with
any STH species decreased substantially between 2007 and 2011, but in 2014 there was an increase in the predicted
number of children infected with A. lumbricoides and T. trichiura. In 2014, the districts with the highest predicted
number of children infected with A. lumbricoides, T. trichiura and hookworms were Kibuye district (n = 128,903),
Mabayi district (n = 35,302) and Kiremba (n = 87,511), respectively.
Conclusions: While the MDA programme in Burundi resulted in a reduction in STH prevalence, this reduction
was spatiotemporally heterogeneous, with some pockets of high prevalence remaining, suggesting that treatment
coverage and complementary interventions should be evaluated to improve impact.
Date Issued
2017-11-23
Date Acceptance
2017-10-29
Citation
Parasites & Vectors, 2017, 10
ISSN
1756-3305
Publisher
BioMed Central
Journal / Book Title
Parasites & Vectors
Volume
10
Copyright Statement
© The Author(s). 2017 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
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
License URL
Subjects
Science & Technology
Life Sciences & Biomedicine
Parasitology
Tropical Medicine
Spatiotemporal modelling
Soil-transmitted helminths
Predictive risk mapping
Number of infections
NEGLECTED TROPICAL DISEASES
INTEGRATED CONTROL
HEALTH-EDUCATION
SPATIAL-ANALYSIS
WEST-AFRICA
SCHISTOSOMIASIS
SANITATION
IMPACT
EPIDEMIOLOGY
TRANSMISSION
Publication Status
Published
Article Number
583