Schistosomiasis control in the people's Republic of China.

Evidence exists that schitosomiasis japonica has been present in China for more than 2,200 years. The first parasitologically confirmed clinical case was reported in 1905. Fragmentary surveys before 1949 suggested that there were 5 million schistosomiasis patients distributed in 138 hsiens (counties); however, a more systematic survey after the founding of the People's Republic showed that these figures represented only 50% of patients and 40% of infected hsiens. Based on the epidemiological pattern and ecological characteristics of the snail intermediate host, endemic areas have been divided into three strata: plain region, mountainous and hill region, and marshland and lake region. Following comprehensive control measures, with stress on applied research and integrating technical work with involvement of the population, in 204 hsiens the snail control programs are now considered to be relatively consolidated and the number of patients needing treatment is relatively few. In the marshland and lake region and mountainous region eradication of schistosomiasis remains a difficult problem.