Anthelmintic activity of artesunate against Fasciola hepatica in naturally infected sheep.

In light of rapidly spreading triclabendazole resistance alternative fasciocidal drugs are urgently needed. Following up on promising results obtained with artemether in Fasciola hepatica infected sheep, we here report the efficacy and safety of artesunate in sheep with a natural F. hepatica infection. Artesunate was administered intravenously and intramuscularly, adverse events were monitored and drug efficacy was elucidated by means of faecal egg and worm burden reductions. A single 40 mg/kg intravenous dose of artesunate induced an egg count reduction of 68.9% and a worm burden reduction of 77.4%. Intramuscular artesunate at 40 mg/kg reduced faecal egg count and worm burden by 97.6% and 91.9%, respectively; whereas at 60 mg/kg it caused 93.2% and 87.1% reduction in faecal egg count and worm burden, respectively. Three sheep died 24-72 h post-treatment with a double dose of 40 mg/kg intramuscular artesunate, showing lethargy, sialorrhoea, reduced rumination and tremors. Egg and worm burden reductions of 93.3% and 83.9%, respectively, were calculated in the three surviving sheep. In conclusion, the interesting fasciocidal properties of artesunate in sheep warrant further investigations with an emphasis on toxicity studies.