Pathogenic factors in the later pulmonary phase of Angiostrongylus cantonensis-infected rats

[Effect of the anthelminthic levamisole on the first-stage larva of Angiostrongylus cantonensis in infected rats]

Effects of levamisole, orally administered at 1, 3, 5 or 7 successive daily doses of 30 mg/kg, on the number of first-stage larvae of Angiostrongylus cantonensis released in the faeces of treated rats were examined. First-stage larval counts (larvae per gram of faeces per female worm recovered, LPG/female) were conspicuously reduced 1 day after administration in all treated groups. In the group treated with a single dose, the larval counts increased 2 days after administration, but no larvae could be detected in the other treated groups. Histological observations of lung tissues of the host showed the degenerative changes in the reproductive system of the worms. These results suggest that levamisole affects the larval output of A. cantonensis through a direct paralyzing action and an indirect mode of action including inhibition in energy metabolism.