[Endemic features and control strategies of schistosomiasis in Dongting Lake area, Hunan Province, P. R. China].

This paper describes the epidemic status and current endemic features of schistosomiasis in Dongting Lake area and analyzes the achievements and weakness of various control measures. It also summarizes the characteristics of epidemic situation in the Dongting Lake region, which indicates the long-term and the arduous work in the future for the control of schistosomiasis. In strategy, comprehensive measures should be implemented and routine prevention control work should be remained combing with the control of transmission sources.

[The use of unsupervised classification of Landsat-5 TM images in analysing the types of vegetation in the areas of "breaking dikes or opening sluice for water store"].

Objective: To clarify the change of vegetation types and its relationship between the density of alive-snails in the areas of "breaking dikes or opening sluice for water store" in Jicheng.

Methods: Synthesized false color images of Jicheng before and after 1998 (1994 and 2003) were classified without supervision and results were compared. Vegetation types were identified on the spot.

[Application of "time series analysis" in the prediction of schistosomiasis prevalence in areas of "breaking dikes or opening sluice for waterstore" in Dongting Lake areas, China].

Objective: To provide the fittest model for forecasting schistosomiasis prevalence in Haokou village of "breaking dikes or opening sluice for waterstore" in Dongting Lake areas by comparing the results of Moving Average, Exponential Smoothing, Autoregressive Model and Autoregressive integrated moving average model (ARIMA model) from 1990 to 2002.

Methods: Error sum of square of four statistical methods was compared and the fittest model was chosen.

Results: Error sum of square of predicted schistosomiasis prevalence rates in Haokou village from 1994 to 2002 were 39.

Relationship between the transmission of schistosomiasis japonica and the construction of the Three Gorge Reservoir.

Objective: To study the relationship between the changes of environment and the transmission of Schistosomiasis japonica after the construction of the Three Gorge Reservoir.

Methods: On the basis of the predictive data on changes of water level and sediment in the middle and lower reaches of the Yangtze River after the dam construction provided by the Yangtze River Committee on Water Conservancy, corresponding data were collected and analyzed. In order to understand the effects of changes of water level and sediment on Oncomelania hupensis, the intermediate host of Schistosoma japonicum, field surveys and ecologically intimated experiments were done.