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Are poor responses to praziquantel for the treatment of Schistosoma mansoni infections in Senegal due to resistance? An overview of the evidence

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Show simple item record Gryseels, B. en_US Mbaye, A. en_US de Vlas, S. J. en_US Stelma, F. F. en_US Guissé, F. en_US van Lieshout, L. en_US Faye, D. en_US Diop, M. en_US Tchuem Tshuenté, L. A. en_US Engels, D. en_US Polman, K. en_US 2007-12-06T14:33:34Z 2007-12-06T14:33:34Z 2001 en_US
dc.identifier.issn 1360-2276 en_US
dc.identifier.other ITG-P1A en_US
dc.identifier.other ITG-P2B en_US
dc.identifier.other ITG-P10B en_US
dc.identifier.other ITG-X11P en_US
dc.identifier.other ITG-PLA en_US
dc.identifier.other PARAS en_US
dc.identifier.other U-SCHISTO en_US
dc.identifier.other DIREC en_US
dc.identifier.other JIF en_US
dc.identifier.other DOI en_US
dc.identifier.other FTB en_US
dc.identifier.other ABSTRACT en_US
dc.description The definitive version is available at
dc.description.abstract This paper summarizes and concludes in-depth field investigations on suspected resistance of Schistosoma mansoni to praziquantel in northern Senegal. Praziquantel at 40 mg/kg usually cures 70–90% of S. mansoni infections. In an initial trial in an epidemic S. mansoni focus in northern Senegal, only 18% of the cases became parasitologically negative 12 weeks after treatment, although the reduction in mean egg counts was within normal ranges (86%). Among other hypotheses to explain the observed low cure rate in this focus, the possibility of drug resistance or tolerance had to be considered. Subsequent field trials with a shorter follow-up period (6–8 weeks) yielded cure rates of 31–36%. Increasing the dose to 2 × 30 mg/kg did not significantly improve cure rates, whereas treatment with oxamniquine at 20 mg/kg resulted in a normal cure rate of 79%. The efficacy of praziquantel in this focus could be related to age and pre-treatment intensity but not to other host factors, including immune profiles and water contact patterns. Treatment with praziquantel of individuals from the area residing temporarily in an urban region with no transmission, and re-treatment after 3 weeks of non-cured individuals within the area resulted in normal cure rates (78–88%). The application of an epidemiological model taking into account the relation between egg counts and actual worm numbers indicated that the low cure rates in this Senegalese focus could be explained by assuming a 90% worm reduction after treatment with praziquantel; in average endemic situations, such a drug efficacy would result in normal cure rates. Laboratory studies by others on the presence or absence of praziquantel resistance in Senegalese schistosome strains have so far been inconclusive. We conclude that there is no convincing evidence for praziquantel-resistant S. mansoni in Senegal, and that the low cure rates can be attributed to high initial worm loads and intense transmission in this area. en_US
dc.language English en_US
dc.publisher Blackwell Publishing
dc.subject Helminthic diseases en_US
dc.subject Schistosoma mansoni en_US
dc.subject Anthelmintics en_US
dc.subject Praziquantel en_US
dc.subject Treatment failure en_US
dc.subject Drug resistance en_US
dc.subject Modeling en_US
dc.subject Review en_US
dc.subject Senegal en_US
dc.subject Africa, West en_US
dc.subject Review of the literature en_US
dc.subject Senegal en_US
dc.subject Africa, West en_US
dc.title Are poor responses to praziquantel for the treatment of Schistosoma mansoni infections in Senegal due to resistance? An overview of the evidence en_US
dc.type Article en_US
dc.citation.jtitle Tropical Medicine and International Health en_US
dc.citation.volume 6 en_US
dc.citation.pages 864-873 en_US Oxford
dc.citation.jabbreviation Trop Med Int Health en_US

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