Objective To analyze the current endemic situation of schistosomiasis and evaluate the control effects of the implementation of comprehensive management measures for 4 years,so as to provide references for making control strategy in the next stage. Methods The endemic villages were grouped into categories based on egg positive rates of fecal examinations among villagers. Praziquantel chemotherapy regimens were provided for villagers and domestic animals,respectively. Snail control on the basis of niclosamide was conducted in snail habitat areas in the hilly area and inside embankment in Dongting Lake,and in infected snail distributed areas outside the embankment in the lake. A slow releasing formation of niclosamide were applied for cercariae killing in transmission areas outside the embankment in the lake in the flood season. The modification of snail habitat areas was integrated into the water conservancy and agricultural development projects. The varied health education,safe water supply and disinfestation toilet facilities were provided for residents in the community. Results The infection rate of schistosomiasis in residents dropped by 49.88%,and the estimated patients reduced by 39.62%. Acute schistosomiasis cases significantly decreased. The total number of advanced schistosomiasis cases slightly increased. The infection rate of schistosomiasis in livestock dropped by 66.36% and snail areas reduced by 33.31% as well as no infected snails were found inside the embankment. Yet,the total areas of snail habitats and distributed areas of infected snails slightly increased,with a high density. The first scale of villages and the second scale of villages were lowered into the third or fourth scale of villages. Out of 31 endemic counties (districts,farms),7 reached the criteria of transmission control,24 reached the criteria of infection control. Conclusions The implementation of the comprehensive management measure has achieved the anticipated results of reducing the infection rate of schistosomiasis among villagers and dropping the incidence of acute schistosomiasis. Yet the snail area on beaches outside the embankment slightly increases,with a high density of infected snails and so there is an infection danger there.

Objective To analyse the effects of Word Bank Loan Schistosomiasis Control Project in Hunan Province from 1992 to 2000. Methods The administrative villages in Hunan endemic areas were divided into heavy, moderate and low zones respectively, based on human infection rates. Control strategies including a major approach of chemotherapy to inhabitants and bovines with praziquantel, complemented with health education as well as snail control by environment modification, were adopted in each endemic zone. Schistosomiasis prevalence surveillance was carried out in 50 moving pilots selected from endemic villages in each zone every year. Results At the beginning of the programm, there were total of 35 endemic counties (cities, districts, farms) and 471 endemic towns in Hunan Province. Up to 2000, 8 endemic counties (farms) reach the transmission interruption criteria, and 25 counties and 300 towns reach the transmission control criteria. Heavy endemic villages decreased from 762 to 271, while moderate endemic villages from 1728 to 1053, and low endemic villages increased from 1447 to 2716. Human infection rates dropped from 11.59% to 5.64%. Conclusion The schistosomiasis epidemic situation decreased obviously after implementing the project in Hunan Province.

Objective To understand endemic diversity on schistosomiasis transmission after reserving plain for flooding. Methods In two study pilots, Jicheng and Qingshanhu, epidemiological factors were investigated longitudinally, and the effectiveness of the interventions was evaluated. Results The infection rates of mobile people who engaged in activities in the discarded plain were increased year by year. The density of infected snails was high. The snail habitats increased significantly in Jicheng, but decreased in Qingshanhu. The infection rate and number of livestock pastured in the discarded plain increased. In the discarded plain, most of the mobile people came from the local areas, and main activities for water contact were fishing and pasturing. About 90% of local residents migrated into endemic areas, and the others into non-endemic areas. Conclusions The discarded plains were evolving to a serious transmission zone of schistosomiasis. Interventions combined with agriculture and fisher productions can decrease snail-spreading. Schistosomiasis examination and chemotherapy for the migrants to non-endemic areas are vital.

Objective To evaluate the effect of elimination of schistosomiasis infectivity in water body by applying molluscicide on transmission marshland outside an embankment in Dongting Lake.Methods Two patches of transmission marshland with similar Oncomelania snails and infectious snails density in the northern part of eastern Dongting Lake regions were selected as molluscicide trail and control groups,respectively,and the snails and water body infectious indicators were investigated and compared between them.Results Adjusted death rate of snails in the trail group 15 days after applying molluscicide was 94.13%,without infected snails.The infection rate of sentinel mice in the trial group 50 days after applying molluscicide was 100.00%,with average 56.6 worms per mice.The infection rate of sentinel mice in the control group without molluscicide was also 100.00%,with average 147.8 worms per mice.Conclusions In transmission marshland areas outside the embankment of rivers or lakes,it is impossible for focus mollusciciding to eliminate the infectivity of schistosomiasis in water body,yet possible to reduce the degree of infectivity to a certain extent.

Objective To analyze the schistosomiasis epidemic of 4 national pilots in Dongting Lake regions during 5 years period, and provide references for control strategy and policy making. Methods Four longitudinal monitoring pilots were set up in Dongting Lake regions from 2000 to 2004, and the field work in pilots was carried out based on “National Scheme on Schistosomiasis Epidemic Monitoring”. Results During the monitoring period, the infection rate of Schistosoma japonicum kept at 4% in Dongjia, 5% in Xinshang and over 12% in Quanxing, but in Changjiang, the rate was 8.92% in the first year of monitoring period, and stayed at 4% in the next 4 years. For all pilots, 20-49 age group had the highest infection rate, with the rate in male being higher than that in female and centering on the fishermen, farmers and students in occupation. There was the occurrence of acute and new advanced cases. The infection rate in domestic animals was fluctuated at 20%. There was extensive distribution of infected snails on marshlands outside embankments. Conclusion Schistosomiasis is seriously endemic in Dongting Lake regions, and intensive control measures are necessary.

Objective To investigate the distribution and characteristics of advanced schistosomi-asis in Hunan Province in order to provide some references for policy making of the control program. Methods The survey scheme of advanced schistosomiasis was made out, in which investigation variables and diagnostic criteria were standardized. The survey was carried out in the whole province. Results There were 5 405 cases of advanced schistosomiasis, reduced by 21. 64% compared with the registration number in the previous files. The prevalence rate was 8. 69/10 000, of which 16. 21% was new cases, 97. 06% were distributed in lake regions and 2. 94% in hilly regions. Of total cases, 78. 70% was located in transmission areas, 15.64% in transmission controlled areas, and 5. 66% in transmission interrupted areas. Cases with splenomegaly made up 59. 4%, ones with ascitis 37. 30% and colonic granulomatous and dwarfism type 3. 16%. Male cases took up 77.39% and female ones 22.61%. In the splenomegaly type 52.24% of patients had performed splenectomy. The youngest case was 14 years old and the oldest 90 years old. Cases of 50-, 60- age group made up 65. 18%, and 32.7% of cases came from 30-, 40-, 70- age group and 2. 09% from the remaining age groups. Farmer took up 87. 58% of all occupations and others occupied 12. 42%. Conclusion The advanced schistosomiasis cases in Hunan Province are showing the falling tendency, although some new cases occur. The main advanced cases come from the farmer in lake regions.