A brief introduction to a nation-wide sampling survey on schistosomiasis.

A nation-wide sampling survey using a stratified group randomized sampling technique was conducted in 1989 in 8 provinces where schistosomiasis was still endemic. Among 343 sampling spots, 197 were in controlled areas and 146 in endemic areas. 16,953 (10.2%) of 165,834 persons were found infected according to stool examination in the endemic areas with a population of 1.03% of the total in China. The positive rates of stool examination in Hunan, Hubei, Jiangxi, Anhui, Jiangsu, Zhejiang, Yunnan and Sichuan provinces were 14.4%, 13.5%, 5.5%, 8.6%, 0%, 0%, 4.4%, and 16.8%, respectively. Thirty-two (0.1%) out of 34,556 children aged 10-14 years were found infected in the areas where schistosomiasis was under control. Also included in this survey were the relationship between schistosome infection and age, sex, and occupation of the population in the endemic areas, the distribution of snail habitats, the roles of domestic animals in the transmission and epidemiological characteristics of different endemic areas.