A randomized, double-blind, multicenter clinical trial on the efficacy of ivermectin against intestinal nematode infections in China.

To assess the efficacy of ivermectin against intestinal nematode infections, a randomized, double-blind, multicenter clinical trial was carried out in a total of 816 human individuals infected with different nematodes from three counties in China. The subjects were randomly assigned into experimental and control groups and orally given a single dose of 0.1, 0.2, 0.2 and 0.2mg/kg ivermectin against Ascaris lumbricoides, hookworm, Trichuris trichiura and Enterobius vermicularis, respectively. Parallel control groups to each of the ivermectin groups were given a single oral dose of 6.7 mg/kg albendazole. The cure rates with ivermectin and albendazole were 100% (102/102) and 99.0% (101/102) for Ascaris, and 66.7% (68/102) and 67.7% (69/102) for Trichuris, respectively, with no significant difference (P>0.05) between the two treatments. The parasitological cure rates of albendazole were 69.6% (71/102) for hookworm and 94.1% (96/102) for Enterobius, which were significantly higher than ivermectin (33.3% and 52.9%, respectively, P<0.0001). The expulsion of worm in the feces reached its peak 1-2 days after ivermectin treatment. The study showed that ivermectin, with few side effects, could be used as an additional treatment tool for intestinal nematodes, especially for the treatment of Ascaris and Trichuris infections in China.

[Prophylactic effect of artesunate against experimental infection of Schistosoma mansoni].

OBJECTIVE: To study the prophylactic effect of artesunate against the infection of Schistosoma mansoni in mice and its optimal scheme for preventing schistosomiasis mansoni. METHODS: BALB/c mice were infected by tail dipping method with S. mansoni cercariae. Mice were administered orally with artesunate at different developmental stage of the parasite, with different regimens. The reduction rates of total and female worms, the number of eggs in the liver and intestine, and the fecundity were calculated and treated statistically. RESULTS: The optimal dosage of artesunate to prevent murine schistosomiasis was 300 mg/kg. The parasite was found to be especially susceptible to artesunate in its schistosomula stage of 14 and 21 d after infection, resulting in worm reduction rate of 84% and 93% respectively compared with control. High protection was reached with worm reduction rate of 99% by the regimens of 300 mg/kg once a week for 4 consecutive weeks beginning 14 d after infection. The fecundity was significantly suppressed, suggesting that the drug inhibited sexual maturation of female worms. The effective protection could also be gained with prolonged interval time of two weeks with worm reduction rate of 97% and 96% beginning 14 or 21 d after infection. CONCLUSION: Artesunate kills schistosomula and reduces the fecundity of females effectively, the infected mice do not develop schistosomiasis mansoni when treated with artesunate. It's proposed that an optimal scheme for field use be the first administration 14 or 21 days after infection with 1 or 2 weeks interval.

[Clinical observation on the efficacy of ivermectin in the treatment of intestinal nematode infections].

OBJECTIVE: To observe the efficacy and side effects of ivermectin in the treatment of intestinal nematode infections. METHODS: A single dose of ivermectin 0.1, 0.2, 0.2 and 0.2 mg/kg was orally administered to cases with infection of Ascaris, hookworm, Trichuris and Enterobius respectively. A single dose of albendazole 400 mg was used as control. RESULTS: The egg negative conversion rates of ivermectin and albendazole were both 100% (34/34) for Ascaris infection, 17.6% (6/34) and 76.5% (26/34) respectively for hookworm infection, 67.6% (23/34) and 47.1% (16/34) respectively for Trichuris infection, 58.8% (20/34) and 100% (34/34) respectively for Enterobius infection. The worm discharge reached a peak in 1-2 days after treatment. The side effect of ivermectin was mild and transient showing no adverse effect on blood picture, liver function, renal function or ECG. CONCLUSION: Ivermectin shows similar effect on Ascaris with albendazole, better effect on Trichuris and poorer effect on hookworm and Enterobius than albendazole.