Validating Egg-based Diagnostics and Molecular Markers for the Spread of Anthelmintic Resistance
Condition: Soil-transmitted Helminth Infections
MeSH terms: Helminthiasis
Study type: Interventional

Summary: 
      Soil-transmitted helminths (STHs) are a group of parasitic worms that infect millions of
      children in sub-tropical and tropical countries, resulting in malnutrition, growth stunting,
      intellectual retardation and cognitive deficits. To control the morbidity due to these worms,
      school-based deworming programs are implemented, in which anthelminthic drugs are
      administered to children without prior diagnosis. The continued fight against these worms is
      aided by the London declaration on neglected tropical diseases, which helps sustain and
      expand global drug donation program, resulting in an unprecedented growth of deworming
      programs. However, the high degree of drug pressure makes deworming programs vulnerable to
      the development of anthelmintic resistance because they only rely on one drug with sometimes
      suboptimal efficacy and there is no availability of alternative drugs. Moreover, at present,
      there is no surveillance system to monitor the emergence and spread of anthelmintic
      resistance. It remains unclear to what extent the efficacy of drugs may have dropped and
      whether anthelmintic resistance is already present.

      This project aims to strengthen the monitoring and surveillance of drug efficacy and
      anthelmintic resistance in STH programs. As such, it will support deworming programs in their
      quest to eliminate STHs as a public health problem.

      The specific objectives of the first work package are to validate diagnostic tools to monitor
      drug efficacy and the spread of anthelmintic resistance, and to validate molecular markers
      for benzimidazole resistance.

      This study will be conducted at four different sites (Ethiopia, Tanzania, Lao PDR and Brazil)
      and will focus on school-aged children (age 5-14). At baseline subjects will be asked to
      provide a recent stool sample which will be processed using 3 different microscopic
      techniques (KK, Mini-Flotac and FECPAKG2). All children will be treated with a single-oral
      dose of albendazole (ALB) 400 mg and 14-21 days after treatment, a second stool sample will
      be collected from all children to again determine the fecal egg counts. At each sampling,
      stool is stored in preservative. Stored stool will be shipped to Belgium for DNA extraction
      and quantitative PCR (qPCR) analysis. A subset of the samples will be analysed by
      pyrosequencing to evaluate the single nucleotide polymorphisms in the b-tubulin gene. Pooling
      of the stored samples will also be performed to compare with the values obtained from
      analysing individual samples.
    

Detailed description: 
      Background Soil-transmitted helminths (STHs) are a group of parasitic worms that infect
      millions of children in sub-tropical and tropical countries, resulting in malnutrition,
      growth stunting, intellectual retardation and cognitive deficits. To control the morbidity
      due to these worms, school-based deworming programs are implemented, in which anthelminthic
      drugs are administered to children without prior diagnosis. The continued fight against these
      worms is aided by the London Declaration on Neglected Tropical Diseases, which helps sustain
      and expand global drug donation program, resulting in an unprecedented growth of deworming
      programs. to illustrate, in the last four years the coverage of mass drug administration
      (MDA) has doubled from 30 to 60%, and ongoing global efforts are made to ultimately reach the
      milestone of 75% by 2020.

      Threats While the laudable long-term aim is to eliminate STHs as a public health problem by
      2020, and to eventually declare targeted geographical areas free from infections, this high
      degree of drug pressure makes deworming programs vulnerable to the development of
      anthelmintic resistance because the programs only rely on one drug with sometimes suboptimal
      efficacy and there is no availability of alternative drugs.

      Challenges

      At present, there is no surveillance system to monitor the emergence and spread of
      anthelmintic resistance. It remains unclear to what extent the efficacy of drugs may have
      dropped and whether anthelmintic resistance is already present. However, developing such a
      system is not straightforward. Deworming programs typically operate in resource-constrained
      settings, and program managers require some flexibility to minimize both financial and
      technical resources, while ensuring a reliable assessment of the drug efficacy. The most
      important obstacles to globally monitor patterns of changing drug efficacy and spread of
      anthelmintic resistance are the following:

        -  the shortage of diagnostic laboratories with experienced staff to perform the surveys
           and analyze and report the obtained data

        -  the absence of a quality assurance system that guarantees auditable results

        -  the lack of guidance in designing surveys as the programs progresses

        -  the lack of data supporting the validity of molecular markers to detect anthelmintic
           resistance in human STHs

        -  the lack of sensitive and point-of-care tools that allow the detection of low
           frequencies of anthelmintic resistance Main objective This project aims to strengthen
           the monitoring and surveillance of drug efficacy and anthelmintic resistance in STH
           programs. As such, it will support deworming programs in their quest to eliminate STHs
           as a public health problem by 2020.

      The specific objectives of the first part of the project are to validate diagnostic tools to
      monitor drug efficacy and the spread of anthelmintic resistance, and to validate molecular
      markers for benzimidazole resistance.

      Study protocol This study will conducted at four different sites at Africa (Ethiopia and
      Tanzania), Asia (Lao PDR) and Latin-America (Brazil). The selection of these sites is based
      on their experience in assessing drug efficacy and evaluating the performance of diagnostic
      tools, the availability of well-equipped diagnostic facilities and skilled personnel, and
      their national MDA history.

      The study will focus on school-aged children (age of 5 to 14 years). At baseline subjects
      will be asked to provide a recent (within 4 hours) stool sample of at least 9 grams. All
      stool samples will be processed using the FECPAKG2, a duplicate Kato-Katz thick smear (the
      most commonly applied fecal egg count (FEC) technique) and Mini-Flotac (a novel technique
      that has a sensitivity at least equal to that of Kato-Katz). All children providing a stool
      sample will be provided a single-oral dose of ALB 400 mg under supervision. Fourteen to 21
      days after treatment, a second stool sample will be collected from all the children that
      proved positive for any STH species at baseline to determine the FECs.

      At each sampling, 2x 1 gram of stool is stored in preservative for downstream molecular
      analysis. Stored stool will be shipped to Belgium for DNA extraction and qPCR analysis. A
      subset of the samples will be analysed by Pyrosequencing to evaluate the single nucleotide
      polymorphisms in the b-tubulin gene.

      Pooling of the stored samples will also be performed to compare with the values obtained from
      analysing individual samples.

      Data handling Data will first be recorded on specific study record forms. These results will
      then be entered into the custom designed Excel-files by two different data entry clerks to
      minimize errors in data due to incorrect data entry.

      Study management Studies in the different sites will be organized and supported out of Ghent
      University. The project team members will travel to each individual trial site to train local
      personnel in the different coprological techniques and to get them acquainted with the trial
      protocol and documents.
    

Intervention name(s): Albendazole Pill 400mg (GSK)
Intervention type(s): Drug
Intervention description(s): One single dose of 400mg Albendazole is provided at baseline.
Other intervention name(s): Albendazole 400mg form GlaxoSmithKline (Batch Nr: 335726)
Intervention MeSH terms: Albendazole
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: parasitology; helminth infections; diagnosis; drug resistance; albendazole; benzimidazole drugs; Ascaris; Trichuris; hookworm; qPCR; microscopy