Background: The soil-transmitted helminths (STHs) are a group of intestinal worms that infect humans through the contact with worm eggs or larvae present in the soil (referring to their common name). The four main STHs are Ascaris lumbricoides, Trichuris trichiura, and two hookworm species, Necator americanus and Ancylostoma duodenale. In 2010, it was estimated that 1.4 billion people were infected with at least one of the four STH species, resulting in a global burden of approximately 5.2 million disability-adjusted life years. Up-to-date, mass drug administration (MDA) programs, in which a single oral dose of albendazole or mebendazole are periodically administered to school-aged children, are the main strategy to control the morbidity caused by these worms, and these programs have recently received increased political and scientific attention. For example, the global treatment coverage of school-aged children has doubled between 2011 (~30%) and 2016 (~70%). A further upscale in MDA is ongoing with the ultimate goal of treating at least 75% of school-aged children in all endemic countries by 2020.

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 of infections, this high level of drug pressure makes MDA programs highly vulnerable to the development of anthelmintic resistance (AR).

Objectives: the overall goal of the network is to strengthen the monitoring of drug efficacy and detecting of the emergence of AR in STH control programs, and this through a series of different specific goals:

·        development of a tool box for monitoring drug efficacy based on reduction in fecal egg counts (FECs);

·        proof-of-principle of a tool box for detecting of the emergence of AR;

·        pilot a monitoring system in STH endemic country where monitoring efficacy and detection of the emergence of AR is warranted;

·        development of a decision algorithm that guides programs to mitigate the spread of AR;

·        revision of the WHO guidelines on assessment of drug efficacy;

·        establishment of a laboratory network to support monitoring of drug efficacy and detection of the emergence of AR

Methods

Development of a tool box for monitoring drug efficacy based on reduction in fecal egg counts (FECs): we will determine which diagnostic method is best to assess drug efficacy. To minimize the variation in operational procedures across laboratories/countries we will develop the necessary standard operating procedures (SOPs), checklists and training material. In addition, we will determine how to best analyze and provide the necessary tool to analyze data. Final, we will establish a sample repository of field strains.

Proof-of-principle (POC) of a tool box for detecting AR: we will explore genetic markers and how they are linked with changes in drug efficacy. We will compare different methods for AR detection, of which some can potentially be implemented in country, and optimize a sampling strategy to detect the emergence of AR (number of schools and number of children per school).

Pilot a monitoring system in STH endemic countries where monitoring efficacy and detecting of the emergence of AR is warranted: We will field test the aforementioned tool boxes and sampling strategies in a selection of priority countries. In addition, we collect data on the costs to estimate the required technical and financial resources to roll out a global monitoring system.

Development of a decision algorithm that guides programs to mitigate the spread of AR: we will use the data obtained in the pilot study to model when and how programs should change their control strategy in order to mitigate further spread of AR.

Revision of the WHO guidelines on assessment of drug efficacy: based on the outcome of the previous specific objectives, we will revise the current WHO guidelines on the assessment of drug efficacy where necessary. In addition, we will strengthen the capacity of a global surveillance system through a network of national reference laboratories. We will train / support national laboratories which in turn will help strengthening a global surveillance system.