[Experimental studies on the preventive effect of artemether against schistosomal infection]

In order to study the preventive effect of artemether (Art) against schistosomal infection, mice, rabbits and dogs infected with Schistosoma japonicum cercariae were treated intragastrically (ig) with Art on various days after infection. The preventive effect was assessed by total and female worm reduction rate, the number of the animals without female worm, measurement of some parameters relevant to the acute schistosomiasis, and histopathological observation on the liver. The results showed that in mice a promising effect was obtained when an initial dose of Art 300 mg/kg was given ig on d7 after infection with cercariae, followed by repeated dosing every wk for 4 times. In rabbits and dogs treated ig with Art according to above-mentioned appropriate regimen on d7 after infection at a dosage of 10 or 15 mg/kg given every 1 or 2 wk for 2-4 times, the total and female worm reduction rates were 96.8%-100%, and part of the animals were free from female worm. After preventive treatment of the rabbits with Art, the body temperature and eosinophil count were normal and no schistosome egg was found in the feces. When rabbits infected with 48-52 schistosome cercariae once every other day for 5 times were initially treated ig with Art 15 mg/kg on d7 after the first infection, and the same dosing was given repeatedly every 1 or 2 wk for 2-4 times, the total and female worm reduction rates were 97.6%-98.4%. Histopathological observation showed that the above-mentioned infected dogs and rabbits received preventive treatment with Art exhibited a promising protective effect on their livers. The protective effect of Art given every 1 wk on the liver was similar to that of the drug given every 2 wk. The results indicate that Art possesses an effect for prevention of schistosomiasis which could be helpful for reducing infection rate and intensity of infection, and controlling acute schistosomiasis.