prevalence and intensity of soil transmitted helminth infections of children in sub saharan CORD-Papers-2022-06-02 (Version 1)

Title: Prevalence and intensity of soil-transmitted helminth infections of children in sub-Saharan Africa 200018: a geospatial analysis
Abstract: BACKGROUND: Driven by global targets to eliminate soil-transmitted helminths as a public health problem governments have rapidly rolled out control programmes using school and community-based platforms. To justify and target ongoing investment quantification of impact and identification of remaining high-risk areas are needed. We aimed to assess regional progress towards these targets. METHODS: We did a continental-scale ecological analysis using a Bayesian spacetime hierarchical model to estimate the effects of known environmental socioeconomic and control-related factors on the prevalence of soil-transmitted helminths and we mapped the probability that implementation units had achieved moderate-to-heavy intensity infection prevalence of less than 2% among children aged 514 years between Jan 1 2000 and Dec 31 2018. FINDINGS: We incorporated data from 26 304 georeferenced surveys spanning 3096 (60%) of the 5183 programmatic implementation units. Our findings suggest a reduction in the prevalence of soil-transmitted helminths in children aged 514 years in sub-Saharan Africa from 44% in 2000 to 13% in 2018 driven by sustained delivery of preventive chemotherapy improved sanitation and economic development. Nevertheless 1301 (25%) of 5183 implementation units still had an estimated prevalence of moderate-to-heavy intensity infection exceeding the 2% target threshold in 2018 largely concentrated in nine countries (in 1026 [79%] of 1301 implementation units): Nigeria Democratic Republic of the Congo Ethiopia Cameroon Angola Mozambique Madagascar Equatorial Guinea and Gabon. INTERPRETATION: Our estimates highlight the areas to target and strengthen interventions and the areas where data gaps remain. If elimination of soil-transmitted helminths as a public health problem is to be achieved in sub-Saharan Africa by 2030 continued investment in treatment and prevention activities are essential to ensure that no areas are left behind. FUNDING: Bill & Melinda Gates Foundation.
Published: 2020-12-15
Journal: Lancet Glob Health
DOI: 10.1016/s2214-109x(20)30398-3
Author Name: Sartorius Benn
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Author Name: Cano Jorge
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Author Name: Simpson Hope
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Author Name: Tusting Lucy S
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Author Name: Marczak Laurie B
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Author Name: Miller Petrie Molly K
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Author Name: Kinvi Boniface
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Author Name: Zoure Honorat
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Author Name: Mwinzi Pauline
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Author Name: Hay Simon I
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Author Name: Rebollo Maria
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Author Name: Pullan Rachel L
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license: cc-by
source_x: Medline; PMC
pubmed_id: 33338459
pmcid: PMC7786448
has_full_text: TRUE
Keywords Extracted from PMC Text: western-central human Gabon eggs DRC appendix p 64).18 portal lymphatic appendix pp 83–85 Congo Kato-Katz stool Mozambique appendix appendix p 65 appendix pp 69–73 parts appendix pp 60–62 reassessment.33 moderate-to-heavy Out-of-sample appendix p 71 Necator americanus 60–62 ivermectin appendix pp 67–68 topsoil off-sample ... joint GDP children Ancylostoma duodenale appendix p 63 CIs appendix pp 56–59 appendix pp 66–67 appendix p 87 T trichiura Lin's Concordance Correlation Coefficient 52–53).9 high.28 appendix pp 74–76 Ascaris lumbricoides appendix p 82 7·4 appendix pp 54–55 COVID-19 effects.25 p>0·80 exceedance people.2 Madagascar appendix p 55 left Trichuris trichiura 3·9 lumbricoides Madagascar, Zimbabwe Nigeria GDP PPP programmes.31 hookworm.34 Nigeria (247 implementation units two-chain WINBUGS appendix p 86 soil
Extracted PMC Text Content in Record: First 5000 Characters:Soil-transmitted helminths (including Ascaris lumbricoides, Trichuris trichiura, and the hookworms Ancylostoma duodenale and Necator americanus) are among the most widespread of the neglected tropical diseases (NTDs).1, 2, 3 In 2010, soil-transmitted helminths were estimated to infect more than a billion people.2, 4, 5 The past decade has seen substantial progress in the roll out of control measures for soil-transmitted helminths, driven by strengthened collaboration and country commitment and expanded donor support. During this time, the WHO 2020 NTD Roadmap target has been to provide regular anthelmintic treatment to at least 75% of children in settings where infection prevalence in children aged 5–14 years exceeds 20%. By 2018, this goal was nearly met in sub-Saharan Africa, with an estimated 70% of at-risk children receiving regular deworming.5 The new WHO 2030 NTD Roadmap now looks beyond coverage, with a goal of eliminating morbidity associated with soil-transmitted helminths (ie, elimination as a public health problem, defined as a moderate-to-heavy intensity infection prevalence of <2%).6 Although deworming through mass treatment platforms is known to be a highly cost-effective public health intervention,7, 8 little is known regarding the effects of mass treatment on the changing prevalence and intensity of soil-transmitted helminths in children. Such an evaluation has been hampered because, in many endemic countries, control was initiated in the absence of comprehensive baseline data—either due to resource constraints or because anthelmintics were already being delivered through other programmes—and surveys have not been done. In 2016, the WHO Africa Regional Office established the Expanded Special Project to Eliminate NTDs (ESPEN) to provide technical support to national NTD programmes. ESPEN includes the development of a pioneering open-access platform that enables health ministries and stakeholders to share, synthesise, and evaluate subnational programmatic data on multiple NTDs. Here, we incorporate epidemiological and programmatic data collated through this platform into a robust space–time modelling framework, with the aim of producing programmatic implementation unit-level estimates of the prevalence of soil-transmitted helminths infections among children aged 5–14 years across sub-Saharan Africa in 2000–18. Research in contextEvidence before this studyGlobal and national estimates of soil-transmitted helminth burden, incorporating data up to 2010, estimated the prevalence of hookworm in sub-Saharan Africa at 13·6%, Ascaris lumbricoides at 13·6%, and Trichuris trichiura at 11·6%. Estimates for sub-Saharan Africa have been subsequently updated using a geostatistical approach to include additional datapoints up to 2012, resulting in period estimates (before 2000 and from and including 2000) at high resolution. Although these estimates suggested reductions in soil-transmitted helminth infections, their utility for tracking control targets remains limited. To our knowledge, no previous estimates have quantified the effects of preventive chemotherapy and other key determinants of soil-transmitted helminths at implementation unit-year level or estimated the prevalence of moderate-to-heavy intensity infection at scale.Added value of this studyThis study provides estimates of the prevalence of moderate-to-heavy intensity soil-transmitted helminths at the implementation unit level to track progress toward the soil-transmitted helminth goals for 2020 and 2030 and help identify areas at highest risk of not attaining target thresholds. We used a georeferenced database of soil-transmitted helminth prevalence for sub-Saharan Africa, to which we applied a Bayesian space–time model that included key time-varying determinants. We estimate prevalence (with CIs) of infection, and of moderate-to-heavy intensity infection, for each soil-transmitted helminth species by implementation unit among children in 2000–18. Our model improves upon previous efforts by using a longitudinal perspective not included in earlier national or regional estimates, accounting for subnational variation in space–time, and including time-varying preventive chemotherapy, water and sanitation, and socioeconomic patterns. We also include summaries for each country to increase the accessibility to and transparency of our estimates.Implications of all the available evidenceThis space–time analysis quantifies progress towards elimination in 2000–18. Although the prevalence of soil-transmitted helminths has substantially reduced over the past two decades, with consideration of a revised control strategy warranted in many areas, it is still highly unlikely that all areas will achieve the global targets for 2020 and beyond. Our estimates can be used by national programmes and implementing partners to identify areas likely to require reassessment surveys, and areas that still require surveillance or intervention to better target preventive chemo
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