Churcher T. S. auteur aut IRD Pion Sébastien auteur aut IRD Osei-Atweneboana M. Y. auteur aut IRD Prichard R. K. auteur aut IRD Awadzi K. auteur aut IRD Boussinesq Michel auteur aut IRD Collins R. C. auteur aut IRD Whitworth J. A. auteur aut IRD Basanez M. G. auteur aut IRD text journalArticle eng text/pdf born digital access Identification of drug resistance before it becomes a public health concern requires a clear distinction between what constitutes a normal and a suboptimal treatment response. A novel method of analyzing drug efficacy studies in human helminthiases is proposed and used to investigate recent claims of atypical responses to ivermectin in the treatment of River Blindness. The variability in the rate at which Onchocerca volvulus microfilariae repopulate host's skin following ivermectin treatment is quantified using an individual-based onchocerciasis mathematical model. The model estimates a single skin repopulation rate for every host sampled, allowing reports of suboptimal responses to be statistically compared with responses from populations with no prior exposure to ivermectin. Statistically faster rates of skin repopulation were observed in 3 Ghanaian villages (treated 12-17 times), despite the wide variability in repopulation rates observed in ivermectin-naive populations. Another village previously thought to have high rates of skin repopulation was shown to be indistinguishable from the normal treatment response. The model is used to generate testable hypotheses to identify whether atypical rates of skin repopulation by microfilariae could result from low treatment coverage alone or provide evidence of decreased ivermectin efficacy. Further work linking phenotypic poor responses to treatment with parasite molecular genetics markers will be required to confirm drug resistance. Limitations of the skin-snipping method for estimating parasite load indicates that changes in the distribution of microfilarial repopulation rates, rather than their absolute values, maybe a more sensitive indicator of emerging ivermectin resistance. specialized drug resistance helminth parasites Onchocerca volvulus overdispersion 052 106 39 16716-16721 2009 0027-8424 https://www.documentation.ird.fr/hor/fdi:010048258 10.1073/pnas.0906176106 0027-8424 [F B010048258] https://www.documentation.ird.fr/hor/fdi:010048258 https://www.documentation.ird.fr/intranet/publi/2009/10/010048258.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2009-11-09 2017-08-23 fdi:010048258 fre