DIAGNOSIS OF SCHISTOSOMIASIS-JAPONICA IN CHINESE SCHOOLCHILDREN BY ADMINISTRATION OF A QUESTIONNAIRE

This paper describes a rapid, simple, cost-effective questionnaire for screening school-aged children at risk for Asian schistosomiasis in C hina. Five hundred and thirty-two children, aged 8-14 years, were sele cted from 3 schools in an area moderately endemic for Schistosoma japo nicum in Hunan province. The questionnaire, comprising 15 multiple-cho ice questions, was administered by teachers in order to collect both e thnographic and epidemiological data relevant to current S, japonicum infections.This was followed by Kato-Katz thick smear stool examinatio ns, miracidium hatching tests, and soluble egg antigen-enzyme linked i mmunosorbent assays in order to validate the efficacy of the questionn aire approach. The results from a combination of all 3 procedures indi cated that the overall schistosomiasis prevalence in the 3 schools was 29.9% (138/472). Six risk factors (episodes of diarrhoea, frequency o f water contact, school grade attained, weakness, past history of S. j aponicum infection(s), and whether a subject had been previously treat ed for schistosomiasis) in the questionnaire were determined by logist ic regression to be highly statistically significant predictors of ind ividual current infection. The sensitivity (93.7%), specificity (91.9% ) and low cost (c. US$ 0.6/true positive case) associated with the 6 v ariables model make the questionnaire approach a very useful diagnosti c tool for screening marshland and lake communities at high risk for s chistosomiasis in China before selective treatment with praziquantel o r diagnostic follow-up. An even simpler 3 variables 'yes/no' model was derived from the questionnaire and found to be nearly as good at pred icting individual infection (sensitivity 86.2% and specificity exceedi ng 97.6%) and extremely simple to use. If validated in other ecologica l settings in China the questionnaire, modified or as presented here, could be adopted by the national schistosomiasis control programme.