Effect of tribendimidine on adult Echinostoma caproni harbored in mice, including scanning electron microscopic observations

Food-borne trematodiasis is an emerging public health problem with more than 10% of the world's population at risk of infection, yet there are only 2 drugs available for treatment and morbidity control. We assessed the effect of a promising broad-spectrum anthelmintic drug, i.e., tribendimidine, with an experimental focus on adult Echinostoma caproni. Female NMRI mice were infected with 30 E. caproni for 2 wk and then administered single oral doses of tribendimidine ranging between 25 and 500 mg/kg. Three days post-treatment, mice were necropsied, and adult worms were recovered from their intestines. Worm burden reductions were assessed against untreated control mice. In addition, scanning electron microscopic observations were done on adult E. caproni recovered from mice given a single dose of 150 mg/kg tribendimidine intragastrically 2, 4, and 8 hr post-treatment. Worm burden reductions of 100% were achieved at doses of 125 mg/kg and above. Severe damage of the tegument, including extensive peeling, formation of blebs, and structural loss of the definition of collar and tegumentary spines already occurred within 2 hr after drug administration. Our findings call for further investigations using tribendimidine in other trematode-animal models, because this compound shows promising trematocidal activity.