Abstract: AIM: To study the preventive effect of oral artemether (Art) in a schistosomiasis endemic area of mountainous type. METHOD:Three villages of Eryuan County, Dali City, Yunnan Province were selected as the pilot of the study where the infection rate of the snail was 8.7% with a mean density of infected snail of 0.2219/0.11 m.2 and the infection rate of the residents was 16.4%. Residents aged 4-60 in the pilot were selected for study and allocated randomly to Art group and the control group. One month before the performance of prevention with Art, stool examination was carried out in all residents and praziquantel was given orally to the egg-negative residents and egg-positive residents at a single dose of 40 mg/kg and 50 mg/kg, respectively. In Art group, the first dose of 6mg/kg was given to the residents in the late May, i. e., about 15 days after contacting with infested water, followed by repeated dosing every 15 days for 3 times. Placebo(starch) was given to the residents in the control group at the same time as in Art group. The efficacy was evaluated by stool examination 25- 32 days after the last medication. RESULTS: In Art group 13 out of 307 residents examined revealed stool positive with an infection rate of 4.2%, while in the control group 46 out of 306 residents examined showed stool positive with an infection rate of 15%. Meantime, the egg per gram of feces (EPG) determined with the Kato-Katz method was 49.8±28.6 in the cont ro l group and 2818±1017 in A rt group. The differences in infect ion rates and EPG ( s) between the two groups were statistically significant. Furthermore, 4 cases of acute schistosomiasis were seen in the control group, but none was found in Art group. CONCLUSION: In schistosomiasis endemic area of mountainous type, oral Art exhibited a promising preventive effect on both reducing infection rate and controlling acute schistosomiasis.

Key words: Schistosomiasis, acute schistosomiasis, prevention, infection rate, artemether