A Study of the Mode of Action of Hycanthone against Schistosoma Mansoni in Vivo and in Vitro *

Abstract

Schistosomes obtained by perfusion from host animals as early as 2 hours after in vivo treatment with hycanthone and transferred into untreated recipient hamsters died in the recipient host. In contrast, unexposed schistosomes transferred into recipient hamsters treated from 7 days to 36 hours previously showed a normal survival. In vitro treatment of schistosomes with hycanthone concentrations comparable to those used in in vivo studies, followed by transfer of the parasites into normal hamsters, resulted in death of the worms. The time of lethal hycanthone exposure in vitro could be as short as 15 minutes. Hycanthone-resistant schistosomes or immature worms were not affected under similar in vitro conditions. Our data suggest that the schistosomicidal effect of hycanthone is not caused by a host-derived metabolite.