A prevalence-based transmission model for the study of the epidemiology and control of soil-transmitted helminthiasis.

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  • Additional Information
    • Source:
      Publisher: Public Library of Science Country of Publication: United States NLM ID: 101285081 Publication Model: eCollection Cited Medium: Internet ISSN: 1932-6203 (Electronic) Linking ISSN: 19326203 NLM ISO Abbreviation: PLoS One Subsets: MEDLINE
    • Publication Information:
      Original Publication: San Francisco, CA : Public Library of Science
    • Subject Terms:
      Helminthiasis*/drug therapy ; Helminthiasis*/epidemiology ; Helminthiasis*/prevention & control ; Helminths*; Animals ; Feces/parasitology ; Humans ; Mass Drug Administration ; Prevalence ; Sanitation ; Soil/parasitology
    • Abstract:
      Much effort has been devoted by the World Health Organization (WHO) to eliminate soil-transmitted helminth (STH) infections by 2030 using mass drug administration targeted at particular risk groups alongside the availability to access water, sanitation and hygiene services. The targets set by the WHO for the control of helminth infections are typically defined in terms of the prevalence of infection, whereas the standard formulation of STH transmission models typically describe dynamic changes in the mean-worm burden. We develop a prevalence-based deterministic model to investigate the transmission dynamics of soil-transmitted helminthiasis in humans, subject to continuous exposure to infection over time. We analytically determine local stability criteria for all equilibria and find bifurcation points. Our model predicts that STH infection will either be eliminated (if the initial prevalence value, y(0), is sufficiently small) or remain endemic (if y(0) is sufficiently large), with the two stable points of endemic infection and parasite eradication separated by a transmission breakpoint. Two special cases of the model are analysed: (1) the distribution of the STH parasites in the host population is highly aggregated following a negative binomial distribution, and (2) no density-dependent effects act on the parasite population. We find that disease extinction is always possible for Case (1), but it is not so for Case (2) if y(0) is sufficiently large. However, by introducing stochastic perturbation into the deterministic model, we discover that chance effects can lead to outcomes not predicted by the deterministic model alone, with outcomes highly dependent on the degree of worm clumping, k. Specifically, we show that if the reproduction number and clumping are sufficiently bounded, then stochasticity will cause the parasite to die out. It follows that control of soil-transmitted helminths will be more difficult if the worm distribution tends towards clumping.
      Competing Interests: The authors have declared that no competing interests exist.
    • References:
      J Health Care Poor Underserved. 2010 Feb;21(1):53-69. (PMID: 20173255)
      PLoS Med. 2012 Jan;9(1):e1001162. (PMID: 22291577)
      Parasitology. 1985 Apr;90 ( Pt 4):629-60. (PMID: 3892436)
      PLoS Negl Trop Dis. 2019 Mar 21;13(3):e0007196. (PMID: 30897089)
      Adv Parasitol. 1985;24:1-101. (PMID: 3904343)
      PLoS Negl Trop Dis. 2020 Aug 10;14(8):e0008505. (PMID: 32776942)
      Parasitology. 1982 Oct;85 (Pt 2):411-26. (PMID: 6755367)
      J Theor Biol. 1980 Jan 21;82(2):283-311. (PMID: 7374181)
      Nature. 1985 Nov 28-Dec 4;318(6044):323-9. (PMID: 3906406)
      Lancet. 2018 Jan 20;391(10117):252-265. (PMID: 28882382)
      PLoS Negl Trop Dis. 2021 Aug 2;15(8):e0009625. (PMID: 34339450)
      Infect Dis Poverty. 2014 Jul 31;3:21. (PMID: 25110585)
      PLoS Negl Trop Dis. 2015 Aug 20;9(8):e0003897. (PMID: 26291538)
      Nature. 1982 Jun 17;297(5867):557-63. (PMID: 7088139)
      BMJ. 2017 Sep 25;358:j4307. (PMID: 28947636)
      PLoS Negl Trop Dis. 2021 May 13;15(5):e0009373. (PMID: 33983940)
      Parasit Vectors. 2019 May 28;12(1):273. (PMID: 31138266)
      J Theor Biol. 2020 Feb 7;486:110076. (PMID: 31733259)
      Clin Infect Dis. 2019 Jan 1;68(1):96-105. (PMID: 29788074)
      Trends Parasitol. 2003 Dec;19(12):547-51. (PMID: 14642761)
      J Theor Biol. 2018 Sep 14;453:96-107. (PMID: 29800536)
      Epidemics. 2017 Mar;18:38-47. (PMID: 28279454)
      Parasit Vectors. 2017 Jun 12;10(1):291. (PMID: 28606164)
      PLoS Negl Trop Dis. 2018 Jan 18;12(1):e0006195. (PMID: 29346383)
      Matern Child Nutr. 2008 Apr;4 Suppl 1:118-236. (PMID: 18289159)
      Lancet Infect Dis. 2017 Feb;17(2):e64-e69. (PMID: 27914852)
      Parasit Vectors. 2017 Jun 30;10(1):321. (PMID: 28666452)
    • Grant Information:
      MR/R015600/1 United Kingdom MRC_ Medical Research Council
    • Accession Number:
      0 (Soil)
    • Publication Date:
      Date Created: 20220825 Date Completed: 20220829 Latest Revision: 20230208
    • Publication Date:
      20230208
    • Accession Number:
      PMC9409602
    • Accession Number:
      10.1371/journal.pone.0272600
    • Accession Number:
      36006929