METHODOLOGICAL APPROACHES IN A BASE-LINE STUDY OF DIARRHEAL MORBIDITYIN WEANING-AGE CHILDREN IN RURAL ZAIRE

A community-based prospective study of diarrhoeal morbidity of weaning -age children in 18 geographically separate village clusters was condu cted as the baseline phase of a controlled trial of a hygiene educatio n intervention to reduce diarrhoeal diseases in rural Zaire, For 12 we eks trained interviewers collected information at weekly home visits a bout the diarrhoeal morbidity of 2082 children aged 3-35 months. Inclu ded in the analyses were 1914 children (92%) with 9 or more complete w eeks of data. Mothers' reporting of the existence or otherwise of epis odes appeared reliable, and more than 70% of children had at least one episode of diarrhoea during the 12-week study period, the mean number of episodes being 1.9 per child. Reporting of the start and terminati on of diarrhoeal episodes was, however, irregularly distributed among the 7 days between successive home interviews, with 36% of all episode s reported as starting on interview days, and 29% reported as ending t he day before an interview: in each case, only 14% would have been exp ected. After adjusting for these reporting biases, 61% of the episodes lasted 2-4 days, but a number of very long duration were also reporte d, and the mean duration of the episodes was 4.8 days. Children, had, on average, 9.2 days of diarrhoea during the study period. Contrasts w ith previous characterizations of reporting error in diarrhoeal studie s are noted.