In vitro tegumental alterations on adult Fasciola gigantica caused by mefloquine.

Emergence of drug-resistant Fasciola strains has drawn the attention of many authors to alternative drugs. The purpose of this study is to explore the in vitro effect of the antimalarial mefloquine against adult Fasciola gigantica. Light and scanning electron microscopic observations could be used to determine the target of the drug following 6 and 12 h of incubation in medium containing mefloquine at three different concentrations 10, 20 and 30 μg/mL, as morphological changes could be observed. These changes occurred in definite sequences in response to mefloquine, and were consisted of swelling, vacuolization that was later disrupted, leading to desquamation of the tegument, resulting in exposure and disruption of basal lamina and the dislodging of spines. It is concluded that mefloquine presented itself as a drug that might become important in trematode chemotherapy, with the tegument being an important drug target.