Ancylostoma Caninum Clinical Trial
Official title:
The Efficacy of a Single-dose Mebendazole Against Soil-transmitted Helminths in School Children
Objectives:
The overall objective is to monitor efficacy of mebendazole (MBZ) against Soil-Transmitted
Helminths (STH).
The primary objective is:
(1) to monitor the efficacy a single dose 500 mg of mebendazole (MBZ) against
Soil-Transmitted Helminths (STH) infections by means of Faecal Egg Count Reduction (FECR)
and Cure Rate (CR).
The secondary objectives are:
1. to assess the occurrence of Necator americanus and Ancylostoma duodenal.
2. to assess the occurrence of β-tubulin mutations related to resistance before and after
drug administration.
3. to evaluate the role of dogs and pigs as reservoir for zoonotic transmission.
Primary objective:
Following obtaining informed consent, schoolchildren in the target age range group will be
recruited and asked to provide a recent stool sample (an interval of less than 4 hours) that
will be processed to determine the Faecal Egg Count (FEC) for each Soil-Transmitted
Helminths (STH) present. For the initial sampling the aim is to enroll at least 250 infected
children for at least one of the Soil-Transmitted Helminths (STH). This sample size was
selected based on statistical analysis of study power, using random simulations of
correlated over-dispersed Faecal Egg Count data reflecting the variance-covariance structure
in a selection of real Faecal Egg Count (FEC) data sets. This analysis suggested that a
sample size of up to 200 individuals (α = 0.05, power = 80%) was required to detect a 10
percentage point drop from a null efficacy of ~ 80% (mean percentage FEC ∆ per individual)
over a wide range of infection scenarios. Standard power analyses for proportions also
indicated that the detection of a ~10 percentage point drop from a null cure rate required
sample sizes up to 200 (the largest samples being required to detect departures from null
efficacies of around 50%). Given an anticipated non-compliance rate of 25%, a sample of 250
infected subjects was therefore considered necessary at each study site.
All children providing stool samples will be treated with mebendazole (MBZ) single table of
500mg under supervision (chewing + water). The mebendazole (MBZ) will be provided (free) by
the coordinating group. Seven up to fourteen days (maximum interval) after treatment a
second faecal sample will be collected from the children to determine again FEC. Subjects
who are unable to provide a stool sample at follow-up, or who are experiencing a severe
concurrent medical condition or have diarrhea at time of the first sampling, will be
excluded from the study.
Secondary objectives:
In 5 study sites, faecal samples of 100 infected subjects should be preserved before
treatment with mebendazole (MBZ) in one tube (1 gram in 10 ml 70% ethanol). Samples of the
same children should be also preserved again in one tube (1 gram in 10 ml 70% ethanol) after
treatment. Samples have be send to the Laboratory of Parasitology, Ghent University.
The samples, collected before and after treatment will be subsequently examined by molecular
assays the occurrence Necator americanus/Ancylostoma duodenal and the occurrence of
β-tubulin mutations related to resistance.
The samples collected before treatment will be subsequently examined by molecular assays to
assess the role of animals as a reservoir for human Soil-Transmitted Helminths (STH).
Parasitological techniques, determination of Faecal Egg Count of Soil-Transmitted Helminths
(STH). All fecal samples were processed using the McMaster egg counting technique for the
detection and the enumeration of infections with A. lumbricoides, T. trichiura and
hookworms. All study sites are familiar with the technique and McMaster slides were provided
previously.
Molecular assays (Laboratory of Parasitology, Ghent University)and Deoxyribonucleic acid
(DNA) extraction.
DNA of Soil-Transmitted Helminths (STH) will be extracted from the samples preserved in
ethanol 70% using the Qiagen mini stool kit.
Molecular identification of Soil-Transmitted Helminths (STH). The presence of the
Soil-Transmitted Helminths species: Ascaris (n= 2), Trichuris (n = 2) and hookworms (n = 4)
will be assessed using different molecular assays. For the differentiation of Trichuris
species, species-specific polymerase chain reaction (PCR) will be applied. For the
differentiation of Ascaris and the canine hookworms a PCR-Restriction Fragment Length
Polymorphism (PCR-RFLP) will be used. For the human hookworms, a quantitative PCR will be
applied.
Presence of mutations in β-tubulin related to mebendazole (MBZ) resistance This specific
objective will be performed in collaboration with McGill University (Canada).
Statistical analysis. Both Cure Rate (CR) and Faecal Egg Count Reduction (FECR) will be
considered to monitor to efficacy of mebendazole (MBZ) against Soil-Transmitted Helminths.
The statistical analysis will be assessed as described by Vercruysse et al., 2011.
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Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment