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1. Gaining and sustaining schistosomiasis control: study protocol and baseline data prior to different treatment strategies in five African countries.

Author

Ezeamama, Amara E., Chun-La He, Ye Shen, Xiao-Ping Yin, Binder, Sue C., Campbell Jr., Carl H., Rathbun, Stephen, Whalen, Christopher C., N'Goran, Eliézer K., Olsen, Annette, Magnussen, Pascal, Kinung'hi, Safari, Fenwick, Alan, Phillips, Anna, Ferro, Josefo, Karanja, Diana M. S., Mwinzi, Pauline N. M., Montgomery, Susan, Evan Secor, W., and Hamidou, Amina

Subjects
SCHISTOSOMIASIS prevention, SCHISTOSOMIASIS treatment, DISTOMATOSIS, DRUG therapy, CANCER treatment, CANCER chemotherapy, ANIMALS, ANTHELMINTICS, CLINICAL trials, EXPERIMENTAL design, ISOQUINOLINE, PREVENTIVE health services, SCHISTOSOMIASIS, TREMATODA, DISEASE prevalence
Abstract

Background: The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in 2008 to answer strategic questions about schistosomiasis control. For programme managers, a high-priority question is: what are the most cost-effective strategies for delivering preventive chemotherapy (PCT) with praziquantel (PZQ)? This paper describes the process SCORE used to transform this question into a harmonized research protocol, the study design for answering this question, the village eligibility assessments and data resulting from the first year of the study.Methods: Beginning in 2009, SCORE held a series of meetings to specify empirical questions and design studies related to different schedules of PCT for schistosomiasis control in communities with high (gaining control studies) and moderate (sustaining control studies) prevalence of Schistosoma infection among school-aged children. Seven studies are currently being implemented in five African countries. During the first year, villages were screened for eligibility, and data were collected on prevalence and intensity of infection prior to randomisation and the implementation of different schemes of PZQ intervention strategies.Results: These studies of different treatment schedules with PZQ will provide the most comprehensive data thus far on the optimal frequency and continuity of PCT for schistosomiasis infection and morbidity control.Conclusions: We expect that the study outcomes will provide data for decision-making for country programme managers and a rich resource of information to the schistosomiasis research community.Trial Registration: The trials are registered at International Standard Randomised Controlled Trial registry (identifiers: ISRCTN99401114 , ISRCTN14849830 , ISRCTN16755535 , ISRCTN14117624 , ISRCTN95819193 and ISRCTN32045736 ). [ABSTRACT FROM AUTHOR]

Published
2016
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2. What impact will the achievement of the current World Health Organisation targets for anthelmintic treatment coverage in children have on the intensity of soil transmitted helminth infections?

Author

Roy M. Anderson, James E. Truscott, and Hugo C. Turner

Subjects
Ancylostomatoidea, Veterinary medicine, Trichuris, Helminthiasis, Mycology & Parasitology, law.invention, law, 1108 Medical Microbiology, EPIDEMIOLOGY, Anthelmintic, Intestinal Diseases, Parasitic, Child, TRICHURIS-TRICHIURA, Anthelmintics, education.field_of_study, biology, Age Factors, CHEMOTHERAPY, ASCARIS-LUMBRICOIDES, COMMUNITY, Treatment Outcome, Infectious Diseases, Transmission (mechanics), 1117 Public Health And Health Services, Ascaris lumbricoides, Life Sciences & Biomedicine, medicine.drug, INTESTINAL HELMINTHS, TRANSMISSION, Population, World Health Organization, MORBIDITY, AGE, Drug Therapy, Environmental health, Disease Transmission, Infectious, medicine, Animals, Humans, Disease Eradication, education, Science & Technology, Ascaris, Research, Models, Theoretical, biology.organism_classification, medicine.disease, Trichuris trichiura, Parasitology, EGG COUNTS
Abstract

Background It is the aim of the World Health Organisation to eliminate soil-transmitted helminths (STH) as a health problem in children. To this end, the goal is to increase anthelmintic treatment coverage for soil transmitted helminths to reach 75 % in pre-school aged and school aged children by 2020 in endemic countries. In this paper, we use mathematical models to investigate the impact of achieving this goal on the burdens of Ascaris lumbricoides, Trichuris trichuria and hookworm. Methods We employ a deterministic fully age-structured model of STH transmission and mass drug administration to examine the changes in worm burden in response to the known and projected coverage trends in children up to 2020 and beyond. Parameters are estimated from worm expulsion data and age intensity profiles before treatment using maximum likelihood methods. Model validation is performed using reinfection studies for Ascaris and analyses are conducted to assess the sensitivity of the predicted outcomes to variation in parameter estimates including transmission intensity (R0), children’s contributions to the pool of infective stages and drug coverage levels. Results The impact of the required increase in coverage trends are quite different across the three species. Ascaris burdens are reduced dramatically by 2020 with elimination predicted within studied the setting a further 10 years. For Trichuris and hookworm, however, impact is more limited, due to issues of drug efficacy (Trichuris) and distribution of worms in the population (hookworm). Sensitivity analysis indicates that results are largely robust. However, validation against Ascaris data indicates that assumptions concerning re-infection among children may have to be revised. Conclusions The 2020 coverage target is predicted to have a major impact on Ascaris levels by 2020. However, there is evidence from model validation that Ascaris in children is more resilient to treatment than currently assumed in the model. Broader coverage across all age classes is required to break transmission for hookworm and alternative dual drug treatment approaches are needed for Trichuris. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1135-4) contains supplementary material, which is available to authorized users.

Published
2015