title: Mathematical inference on helminth egg counts in stool and its applications in mass drug administration programmes to control soil-transmitted helminthiasis in public health.
abstract: In the present study, we present a hierarchical model based on faecal egg counts (FECs; expressed in eggs per 1g of stool) in which we first describe the variation in FECs between individuals in a particular population, followed by describing the variance due to counting eggs under a microscope separately for each stool sample. From this general framework, we discuss how to calculate a sample size for assessing a population mean FEC and the impact of an intervention, measured as reduction in FECs, for any scenario of soil-transmitted helminth (STH) epidemiology (the intensity and aggregation of FECs within a population) and diagnostic strategy (amount of stool examined (∼sensitivity of the diagnostic technique) and examination of individual/pooled stool samples) and on how to estimate prevalence of STH in the absence of a gold standard. To give these applications the most wide relevance as possible, we illustrate each of them with hypothetical examples.
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Bruno
authors.initials: B
authors.lastname: Levecke
authors.affiliation: Imperial College London, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health St Mary's Campus, Norfolk Place, London, UK.
authors.forename: Roy M
authors.initials: RM
authors.lastname: Anderson
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Berkvens
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Johannes
authors.initials: J
authors.lastname: Charlier
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium; Institute of Health and Society (IRSS), Université catholique de Louvain, Brussels, Belgium.
authors.forename: Brecht
authors.initials: B
authors.lastname: Devleesschauwer
authors.affiliation: Institute of Health and Society (IRSS), Université catholique de Louvain, Brussels, Belgium.
authors.forename: Niko
authors.initials: N
authors.lastname: Speybroeck
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Jozef
authors.initials: J
authors.lastname: Vercruysse
authors.affiliation: Department of Applied Mathematics, Computer Science and Statistics, Faculty of Sciences, Ghent University, Ghent, Belgium; Department of Mathematics, Faculty of Sciences, KU Leuven University, Leuven, Belgium.
authors.forename: Stefan
authors.initials: S
authors.lastname: Van Aelst
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D005243:Feces / Q000469:parasitology*; D006373:Helminthiasis / Q000188:drug therapy* / Q000453:epidemiology / Q000469:parasitology / Q000517:prevention & control*; D006376:Helminths / Q000502:physiology; D006801:Humans; D008962:Models, Theoretical; D010270:Parasite Egg Count; D012987:Soil / Q000469:parasitology*
chemical_list: D000871:Anthelmintics; D012987:Soil
keywords: Anthelminthic resistance; Faecal egg counts; Hierarchical model; Mass drug administration; Monitoring system; Sample size; Soil-transmitted helminths; Survey design; True prevalence