Alveolar echinococcosis (AE) is caused by the metacestode stage of the fox tapeworm Echinococcus multilocularis and causes severe disease in the human liver, and occasionally in other organs, that is fatal when treatment is unsuccessful. The present
chemotherapy against AE is based on
mebendazole and
albendazole.
Albendazole treatment has been found to be ineffective in some instances, is parasitostatic rather than parasiticidal, and usually involves the lifelong uptake of large doses of drugs. Thus, new treatment options are urgently needed. In this study we investigated the in vitro and in vivo efficacy of
mefloquine against E. multilocularis metacestodes. Treatment using
mefloquine (20 μM) against in vitro cultures of metacestodes resulted in rapid and complete detachment of large parts of the germinal layer from the inner surface of the laminated layer within a few hours. The in vitro activity of
mefloquine was dependent on the dosage. In vitro culture of metacestodes in the presence of 24 μM
mefloquine for a period of 10 days was parasiticidal, as determined by murine bioassays, while treatment with 12 μM was not. Oral application of
mefloquine (25 mg/kg of
body weight administered twice a week for a period of 8 weeks) in E. multilocularis-infected mice was ineffective in achieving any reduction of parasite weight, whereas treatment with
albendazole (200 mg/kg/day) was highly effective. However, when the same
mefloquine dosage was applied intraperitoneally, the reduction in parasite weight was similar to the reduction seen with oral
albendazole application. Combined application of both drugs did not increase the treatment efficacy. In conclusion,
mefloquine represents an interesting
drug candidate for the treatment of AE, and these results should be followed up in appropriate in vivo studies.