Reduced efficacy of praziquantel against Schistosoma mansoniis associated with multiple rounds of mass drug administration

Crellen, T., Walker, M., Lamberton, P. H.L. , Kabatereine, N. B., Tukahebwa, E. M., Cotton, J. A. and Webster, J. P. (2016) Reduced efficacy of praziquantel against Schistosoma mansoniis associated with multiple rounds of mass drug administration. Clinical Infectious Diseases, 63(9), pp. 1151-1159. (doi: 10.1093/cid/ciw506) (PMID:27470241) (PMCID:PMC5064161)

Abstract

Background: Mass drug administration (MDA) with praziquantel is the cornerstone of schistosomiasis control in sub-Saharan Africa. The effectiveness of this strategy is dependent on the continued high efficacy of praziquantel; however, drug efficacy is rarely monitored using appropriate statistical approaches that can detect early signs of wane. Methods: We conducted a repeated cross-sectional study, examining children infected with Schistosoma mansoni from 6 schools in Uganda that had previously received between 1 and 9 rounds of MDA with praziquantel. We collected up to 12 S. mansoni egg counts from 414 children aged 6–12 years before and 25–27 days after treatment with praziquantel. We estimated individual patient egg reduction rates (ERRs) using a statistical model to explore the influence of covariates, including the number of prior MDA rounds. Results: The average ERR among children within schools that had received 8 or 9 previous rounds of MDA (95% Bayesian credible interval [BCI], 88.23%–93.64%) was statistically significantly lower than the average in schools that had received 5 rounds (95% BCI, 96.13%–99.08%) or 1 round (95% BCI, 95.51%–98.96%) of MDA. We estimate that 5.11%, 4.55%, and 16.42% of children from schools that had received 1, 5, and 8–9 rounds of MDA, respectively, had ERRs below the 90% threshold of optimal praziquantel efficacy set by the World Health Organization. Conclusions: The reduced efficacy of praziquantel in schools with a higher exposure to MDA may pose a threat to the effectiveness of schistosomiasis control programs. We call for the efficacy of anthelmintic drugs used in MDA to be closely monitored.

• Item Type: Articles
• Additional Information: T. C. was supported by a Medical Research Council studentship. Fieldwork costs were supported by a grant from the Schistosomiasis Control Initiative. M. W. received financial support from the UNICEF/UNDP/World Bank WHO Special Programme for Research and Training in Tropical Disease. J. A. C. is supported by the Wellcome Trust through their core funding of the Wellcome Trust Sanger Institute (grant number 098051).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lamberton, Professor Poppy and Cotton, Professor James
• Authors: Crellen, T., Walker, M., Lamberton, P. H.L., Kabatereine, N. B., Tukahebwa, E. M., Cotton, J. A., and Webster, J. P.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing; College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Clinical Infectious Diseases
• Publisher: Oxford University Press
• ISSN: 1058-4838
• ISSN (Online): 1537-6591
• Published Online: 28 July 2016
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in Clinical Infectious Diseases 63
• Publisher Policy: Reproduced under a Creative Commons License