Validating Egg-based Diagnostics and Molecular Markers for the Spread of Anthelmintic Resistance

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.

Timeline

Start

2016-08-15

Primary completion

2018-01-01

Completion

2019-09-01

Publications

• Coffeng LE, Vlaminck J, Cools P, Denwood M, Albonico M, Ame SM, Ayana M, Dana D, Cringoli G, de Vlas SJ, Fenwick A, French M, Kazienga A, Keiser J, Knopp S, Leta G, Matoso LF, Maurelli MP, Montresor A, Mirams G, Mekonnen Z, Correa-Oliveira R, Pinto SA, Rinaldi L, Sayasone S, Steinmann P, Thomas E, Vercruysse J, Levecke B. A general framework to support cost-efficient fecal egg count methods and study design choices for large-scale STH deworming programs-monitoring of therapeutic drug efficacy as a case study. PLoS Negl Trop Dis. 2023 May 17;17(5):e0011071. doi: 10.1371/journal.pntd.0011071. eCollection 2023 May.
• Walker M, Cools P, Albonico M, Ame SM, Ayana M, Dana D, Keiser J, Matoso LF, Montresor A, Mekonnen Z, Correa-Oliveira R, Pinto SA, Sayasone S, Vercruysse J, Vlaminck J, Levecke B. Individual responses to a single oral dose of albendazole indicate reduced efficacy against soil-transmitted helminths in an area with high drug pressure. PLoS Negl Trop Dis. 2021 Oct 19;15(10):e0009888. doi: 10.1371/journal.pntd.0009888. eCollection 2021 Oct.
• Vlaminck J, Cools P, Albonico M, Ame S, Ayana M, Cringoli G, Dana D, Keiser J, Maurelli MP, Matoso LF, Montresor A, Mekonnen Z, Mirams G, Correa-Oliveira R, Pinto SA, Rinaldi L, Sayasone S, Thomas E, Vercruysse J, Verweij JJ, Levecke B. Therapeutic efficacy of albendazole against soil-transmitted helminthiasis in children measured by five diagnostic methods. PLoS Negl Trop Dis. 2019 Aug 1;13(8):e0007471. doi: 10.1371/journal.pntd.0007471. eCollection 2019 Aug.
• Cools P, Vlaminck J, Albonico M, Ame S, Ayana M, Jose Antonio BP, Cringoli G, Dana D, Keiser J, Maurelli MP, Maya C, Matoso LF, Montresor A, Mekonnen Z, Mirams G, Correa-Oliveira R, Pinto SA, Rinaldi L, Sayasone S, Thomas E, Verweij JJ, Vercruysse J, Levecke B. Diagnostic performance of a single and duplicate Kato-Katz, Mini-FLOTAC, FECPAKG2 and qPCR for the detection and quantification of soil-transmitted helminths in three endemic countries. PLoS Negl Trop Dis. 2019 Aug 1;13(8):e0007446. doi: 10.1371/journal.pntd.0007446. eCollection 2019 Aug.
• Vlaminck J, Cools P, Albonico M, Ame S, Ayana M, Bethony J, Cringoli G, Dana D, Keiser J, Maurelli MP, Montresor A, Mekonnen Z, Mirams G, Correa-Oliveira R, Prichard R, Rashwan N, Rinaldi L, Sayasone S, Thomas E, Verweij JJ, Vercruysse J, Levecke B. Comprehensive evaluation of stool-based diagnostic methods and benzimidazole resistance markers to assess drug efficacy and detect the emergence of anthelmintic resistance: A Starworms study protocol. PLoS Negl Trop Dis. 2018 Nov 2;12(11):e0006912. doi: 10.1371/journal.pntd.0006912. eCollection 2018 Nov.

Drugs

Indications