THE DOT MAP AS AN EPIDEMIOLOGIC TOOL - A CASE-STUDY OF SCHISTOSOMA-MANSONI INFECTION IN AN URBAN SETTING

In this paper dot maps are used as an epidemiological tool to describe the spatial patterns of cases, non-cases and some relevant risk facto rs associated with the occurrence of Schistosoma mansoni infection in an urban environment. The study was carried out in Santo Antonio de Je sus, a town in north-east Brazil with a population of around 45 000 in habitants. The survey was targeted at all children aged between 12 yea rs 8 months and 14 years 11 months who were living in the town at the time of the survey. An extensive questionnaire was used to collect inf ormation on each child and on family and household conditions; stool s amples were also taken for quantitative examination. A computerized di gitizer was used on a map (scale 1:4000) to create x and y coordinates for each child's household. The result was matched with individual da ta from the questionnaires and the stool examination. From this data b ase it was possible, by using a statistical package, to make epidemiol ogical analyses and by using the statistical package associated with a geocartographic system package it was possible to dot plot selected v alues of defined variables. These techniques substantiated the finding s on the risk factors at a local level and, as a consequence, improve our ability to define targeted actions towards local control of schist osomiasis.