Comparison of coproprevalence and seroprevalence to guide decision-making in national soil-transmitted helminthiasis control programs: Ethiopia as a case study.
Journal
PLoS neglected tropical diseases
ISSN: 1935-2735
Titre abrégé: PLoS Negl Trop Dis
Pays: United States
ID NLM: 101291488
Informations de publication
Date de publication:
10 2022
10 2022
Historique:
received:
25
05
2022
accepted:
16
09
2022
entrez:
5
10
2022
pubmed:
6
10
2022
medline:
12
10
2022
Statut:
epublish
Résumé
WHO recommends periodical assessment of the prevalence of any soil-transmitted helminth (STH) infections to adapt the frequency of mass drug administration targeting STHs. Today, detection of eggs in stool smears (Kato-Katz thick smear) remains the diagnostic standard. However, stool examination (coprology) has important operational drawbacks and impedes integrated surveys of multiple neglected tropical diseases. Therefore, the aim of the present study was to assess the potential of applying serology instead of coprology in STH control program decision-making. An antibody-ELISA based on extract of Ascaris lung stage larvae (AsLungL3-ELISA) was applied in ongoing monitoring activities of the Ethiopian national control program against schistosomiasis and soil-transmitted helminthiasis. Blood and stool samples were collected from over 6,700 students (median age: 11) from 63 schools in 33 woredas (districts) across the country. Stool samples of two consecutive days were analyzed applying duplicate Kato-Katz thick smear. On woreda level, qualitative (seroprevalence) and quantitative (mean optical density ratio) serology results were highly correlated, and hence seroprevalence was chosen as parameter. For 85% of the woredas, prevalence based on serology was higher than those based on coprology. The results suggested cross-reactivity of the AsLungL3-ELISA with Trichuris. When extrapolating the WHO coproprevalence thresholds, there was a moderate agreement (weighted κ = 0.43) in program decision-making. Using the same threshold values would predominantly lead to a higher frequency of drug administration. This is the first time that serology for soil-transmitted helminthiasis is applied on such large scale, thereby embedded in a control program context. The results underscore that serology holds promise as a tool to monitor STH control programs. Further research should focus on the optimization of the diagnostic assay and the refinement of serology-specific program decision-making thresholds.
Sections du résumé
BACKGROUND
WHO recommends periodical assessment of the prevalence of any soil-transmitted helminth (STH) infections to adapt the frequency of mass drug administration targeting STHs. Today, detection of eggs in stool smears (Kato-Katz thick smear) remains the diagnostic standard. However, stool examination (coprology) has important operational drawbacks and impedes integrated surveys of multiple neglected tropical diseases. Therefore, the aim of the present study was to assess the potential of applying serology instead of coprology in STH control program decision-making.
METHODOLOGY
An antibody-ELISA based on extract of Ascaris lung stage larvae (AsLungL3-ELISA) was applied in ongoing monitoring activities of the Ethiopian national control program against schistosomiasis and soil-transmitted helminthiasis. Blood and stool samples were collected from over 6,700 students (median age: 11) from 63 schools in 33 woredas (districts) across the country. Stool samples of two consecutive days were analyzed applying duplicate Kato-Katz thick smear.
PRINCIPAL FINDINGS
On woreda level, qualitative (seroprevalence) and quantitative (mean optical density ratio) serology results were highly correlated, and hence seroprevalence was chosen as parameter. For 85% of the woredas, prevalence based on serology was higher than those based on coprology. The results suggested cross-reactivity of the AsLungL3-ELISA with Trichuris. When extrapolating the WHO coproprevalence thresholds, there was a moderate agreement (weighted κ = 0.43) in program decision-making. Using the same threshold values would predominantly lead to a higher frequency of drug administration.
SIGNIFICANCE
This is the first time that serology for soil-transmitted helminthiasis is applied on such large scale, thereby embedded in a control program context. The results underscore that serology holds promise as a tool to monitor STH control programs. Further research should focus on the optimization of the diagnostic assay and the refinement of serology-specific program decision-making thresholds.
Identifiants
pubmed: 36197895
doi: 10.1371/journal.pntd.0010824
pii: PNTD-D-22-00678
pmc: PMC9534397
doi:
Substances chimiques
Soil
0
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
e0010824Déclaration de conflit d'intérêts
The authors have declared that no competing interests exist.
Références
Vet Parasitol. 2019 Apr;268:67-72
pubmed: 30981308
PLoS Negl Trop Dis. 2020 Apr 13;14(4):e0008037
pubmed: 32282815
Parasit Vectors. 2020 Sep 1;13(1):437
pubmed: 32873333
Lancet. 2006 May 6;367(9521):1521-32
pubmed: 16679166
Parasite Immunol. 2006 Jul;28(7):285-93
pubmed: 16842265
PLoS Negl Trop Dis. 2021 Jan 22;15(1):e0009032
pubmed: 33481808
PLoS Negl Trop Dis. 2013 Dec 05;7(12):e2588
pubmed: 24340121
Vet Parasitol. 2012 Oct 26;189(2-4):267-73
pubmed: 22560331
PLoS Negl Trop Dis. 2021 Apr 28;15(4):e0009369
pubmed: 33909616
Trans R Soc Trop Med Hyg. 2007 Feb;101(2):140-5
pubmed: 16824566
PLoS Negl Trop Dis. 2018 Jan 18;12(1):e0005988
pubmed: 29346376
Vet Parasitol. 2015 Jul 30;211(3-4):306-11
pubmed: 26095952
Rev Infect Dis. 1991 Sep-Oct;13(5):1018-22
pubmed: 1962076
Parasit Vectors. 2018 Jan 25;11(1):59
pubmed: 29370855
PLoS Negl Trop Dis. 2021 Sep 14;15(9):e0009740
pubmed: 34520474
PLoS Negl Trop Dis. 2018 Jan 18;12(1):e0006166
pubmed: 29346377
Lab Anim. 2001 Jul;35(3):205-12
pubmed: 11463066
PLoS Negl Trop Dis. 2021 Dec 9;15(12):e0009908
pubmed: 34882670
Vet Parasitol. 2015 Jun 15;210(3-4):151-8
pubmed: 25952722
Parasit Vectors. 2009 Feb 10;2(1):11
pubmed: 19208229
Vet Parasitol. 2011 Aug 4;180(1-2):72-81
pubmed: 21684689
Parasit Vectors. 2017 Feb 17;10(1):93
pubmed: 28212667
Parasitol Today. 2000 Dec;16(12):540-4
pubmed: 11121853
Lancet. 2012 Jan 28;379(9813):289-90
pubmed: 22284644
PLoS Negl Trop Dis. 2012;6(7):e1746
pubmed: 22860146
PLoS Negl Trop Dis. 2020 Dec 31;14(12):e0008933
pubmed: 33382694
Vet Parasitol. 2017 Dec 15;248:33-38
pubmed: 29173538
Vet Parasitol. 2019 Jan;265:85-90
pubmed: 30638525
PLoS Negl Trop Dis. 2008 Oct 01;2(10):e297
pubmed: 18827883
PLoS Negl Trop Dis. 2018 Mar 01;12(3):e0006213
pubmed: 29494581
Vet Parasitol. 2017 Nov 15;246:82-87
pubmed: 28969785
PLoS Negl Trop Dis. 2021 Jun 3;15(6):e0009422
pubmed: 34081694
Parasit Vectors. 2017 Jun 30;10(1):321
pubmed: 28666452
PLoS Negl Trop Dis. 2016 Mar 18;10(3):e0004532
pubmed: 26991326
PLoS Negl Trop Dis. 2022 Apr 8;16(4):e0010353
pubmed: 35394996
Nature. 2011 Oct 26;479(7374):529-33
pubmed: 22031327
Microbes Infect. 2021 Sep-Oct;23(8):104836
pubmed: 34020024
Trans R Soc Trop Med Hyg. 2021 Jan 28;115(2):129-135
pubmed: 33169166
Nature. 1993 Oct 28;365(6449):797-805
pubmed: 8413664
PLoS Negl Trop Dis. 2018 Mar 26;12(3):e0006325
pubmed: 29579038
Parasitology. 2014 Dec;141(14):1904-11
pubmed: 24775944
PLoS Negl Trop Dis. 2022 Jan 18;16(1):e0010131
pubmed: 35041666
Parasitology. 1997 Oct;115 ( Pt 4):439-42
pubmed: 9364571
J Infect Dis. 2022 Apr 19;225(8):1435-1446
pubmed: 32524140
Lancet. 2020 Oct 17;396(10258):1204-1222
pubmed: 33069326
Parasit Vectors. 2019 Oct 29;12(1):503
pubmed: 31665080
Ethiop Med J. 2017;55(Suppl 1):55-63
pubmed: 28878430