The investigation of related cases for the control of diarrhea in cities in developing countries

An example of how follow-up of related cases of diarrhea by epidemiologically-oriented health promoters can result in important public health measures is described. The follow-up of related cases involved a search for an outbreak in which a population with a high attack rate could be defined in order to increase the likelihood of a successful investigation by means of a cross-sectional retrospective study design. Then, through standard epidemiologic techniques, the risk factors to be studied were selected and a questionnaire was designed and executed. The results of this investigation demonstrate that greater meticulousness in pursuing epidemiologic principles is required for success in diarrhea outbreak investigations in developing countries than in developed countries despite the fact that controllable contaminations discoverable by these techniques are much more frequent in the former. In the present investigation it was found that flavored drinks packaged in plastic by a process assuming increasing importance in food distribution were causing diarrhea because of unhygienic manufacturing procedures. A concomitant bacteriologic study helped confirm the epidemiologic findings, and bacteriologic cultures at different points in the manufacturing process suggested a solution to the contamination problem found.