Anthelmintic effect of levamisole against Angiostrongylus cantonensis in mice.

Levamisole, in dosages of 2.5, 5, 10, and 25 mg/kg/day, was given orally by orogastric tube beginning 5, 10, 15, and 20 days after the infection of ICR mice with 50 third-stage larvae of Angiostrongylus cantonensis. Medication was given for 7, 14 or 21 consecutive days. The mice in each group were sacrificed 3 days after cessation of treatment and the brains were examined for parasites. Complete anthelmintic effects could be obtained when treatment was started 10 days post-infection with dosages as low as 2.5 mg/kg/day for 21 consecutive days. Over 90% worm reduction was achieved in the two-week treatment group with medication beginning 5 days after infection at diverse dosages. High dose were given in the treatment groups beginning 15 days post-infection. When the commencement of medication was delayed to 20 days post-infection, worm reduction rates were around 50% in spite of long periods and/or high dosages of medication.