title: Effect of sampling and diagnostic effort on the assessment of schistosomiasis and soil-transmitted helminthiasis and drug efficacy: a meta-analysis of six drug efficacy trials and one epidemiological survey.
abstract: It is generally recommended to perform multiple stool examinations in order to improve the diagnostic accuracy when assessing the impact of mass drug administration programmes to control human intestinal worm infections and determining efficacy of the drugs administered. However, the collection and diagnostic work-up of multiple stool samples increases costs and workload. It has been hypothesized that these increased efforts provide more accurate results when infection and drug efficacy are summarized by prevalence (proportion of subjects infected) and cure rate (CR, proportion of infected subjects that become egg-negative after drug administration), respectively, but not when these indicators are expressed in terms of infection intensity and egg reduction rate (ERR). We performed a meta-analysis of six drug efficacy trials and one epidemiological survey. We compared prevalence and intensity of infection, CR and ERR based on collection of one or two stool samples that were processed with single or duplicate Kato-Katz thick smears. We found that the accuracy of prevalence estimates and CR was lowest with the minimal sampling effort, but that this was not the case for estimating infection intensity and ERR. Hence, a single Kato-Katz thick smear is sufficient for reporting infection intensity and ERR following drug treatment.
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine,Ghent University,Salisburylaan 133, 9820 Merelbeke,Belgium.
authors.forename: Bruno
authors.initials: B
authors.lastname: Levecke
authors.affiliation: Department of Disease Control,London School of Hygiene & Tropical Medicine,Keppel Street, London WC1E 7HT,UK.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Brooker
authors.affiliation: Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences,Natural History Museum,Cromwell Road, London SW7 5BD,UK.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Knopp
authors.affiliation: Department of Epidemiology and Public Health,Swiss Tropical and Public Health Institute,Socinstrasse 57, CH-4002 Basel,Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Steinmann
authors.affiliation: Department of Infectious and Tropical Diseases,London School of Hygiene & Tropical Medicine,Keppel Street, London WC1E 6HT,UK.
authors.forename: Jose Carlos
authors.initials: JC
authors.lastname: Sousa-Figueiredo
authors.affiliation: Department of Parasitology,Liverpool School of Tropical Medicine,Liverpool L3 5QA,UK.
authors.forename: J Russell
authors.initials: JR
authors.lastname: Stothard
authors.affiliation: Department of Epidemiology and Public Health,Swiss Tropical and Public Health Institute,Socinstrasse 57, CH-4002 Basel,Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine,Ghent University,Salisburylaan 133, 9820 Merelbeke,Belgium.
authors.forename: Jozef
authors.initials: J
authors.lastname: Vercruysse
mesh_terms: D000818:Animals; D005243:Feces / Q000469:parasitology; D006373:Helminthiasis / Q000175:diagnosis* / Q000188:drug therapy / Q000469:parasitology; D006376:Helminths / Q000302:isolation & purification*; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000175:diagnosis* / Q000188:drug therapy / Q000469:parasitology; D008297:Male; D010270:Parasite Egg Count / Q000191:economics / Q000379:methods; D015995:Prevalence; D012547:Schistosoma / Q000302:isolation & purification*; D012552:Schistosomiasis / Q000175:diagnosis* / Q000188:drug therapy / Q000469:parasitology; D012987:Soil / Q000469:parasitology; D013048:Specimen Handling / Q000379:methods*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D012987:Soil