CONICET | Buscador de Institutos y Recursos Humanos

Cystic echinococcosis (CE) is a worldwide zoonotic disease causedby Echinococcus granulosus, which produces long-term infections inhumans and animals. Available anti-parasitic treatment against CEis mostly limited to the use of benzimidazoles, mainly albendazole(ABZ). However, it has undesirable side effects and their efficacy isabout 50%. Based on the problematic described, new treatment al-ternatives are urgently needed. Plants from the Stevia genus (As-teraceae) are a potential source of anti-protozoal and anti-microbialcompounds. The aim of the present study was to evaluate the invitro and in vivo efficacy of the Stevia aristata dichloromethane ex-tract against E. granulosus. Viable and free protoscoleces or cystswere treated with 100, 50, 10 and 5 μg/ml of the extract. Viabilityassessment using the methylene blue exclusion test and scanningelectron microscopy (SEM) (for protoscoleces) or evaluation of ger-minal layer collapse (for cysts) was performed. CF-1 mice (n=30)infected with E. granulosus were allocated into the following exper-imental groups (6 months post-infection): (1) Control, (2) ABZ 25mg/kg, every 24 h for 30 days; (3) S. aristata 50 mg/kg, every 24 hfor 23 days. At the end of the treatment the weight of the cysts wasrecorded and samples were analysed by SEM. Protoscoleces via-bility decreased quickly with 100 μg/ml, reaching 0% after 20 daysof treatment. After 4 days of incubation, the collapse of the germinallayer was observed in 60 ± 5.8% and 83.3 ± 12.0% of cysts treatedwith 50 and 100 μg/ml, respectively. Whilst ultrastructural damagewas observed in the cysts obtained from S. aristata or ABZ treatedmice, no significant differences in the weight of the cysts were ob-tained (P > 0.05). In conclusion, S. aristata treatment caused highprotoscolicidal and cysticidal effects, but not significant reduction inthe weight of the cysts in experimentally infected mice.