RESUMO
BACKGROUND: In August 2006 a physician from a rural village reported an outbreak of acute gastroenteritis. An investigation was undertaken in order to determine the magnitude of the outbreak, the source of infection and to prevent further disease. This is the first published outbreak of acute gastroenteritis caused by contaminated drinking water in Austria. METHODS: For descriptive epidemiology, the investigators had to rely on voluntary cooperation from physicians and patients, data collected by a police officer and data on sick leave reported by physicians to the health insurance system. RESULTS: Microbiological testing of water samples indicated that this cluster was caused by fecal contamination of untreated drinking water. Age and sex distributions were available for 146 of 160 cases: ages ranged from 5 to 91 years (median 45) and 81 cases (55.5%) were female. Stool samples from 14 patients were sent for microbiological analysis: all tested negative for Salmonella, Campylobacter, Shigella and Yersinia enterocolitica. Specimens were not tested for viruses, parasites or enteropathogenic Escherichia coli. DISCUSSION: In this outbreak no identification was made of pathogenic microorganisms in stool samples from affected patients, despite the occurrence of fecal indicator organisms in samples of drinking water. In outbreaks of gastroenteritis, medical practitioners should encourage microbiological testing beyond the limited routine program. Public health officers must be made aware that the spectrum of routine laboratory tests on stool specimens does not cover the wide array of pathogens capable of causing waterborne outbreaks. The springs serving the affected village originate in a mountainous area of karst formations, and heavy falls of rain that occurred at the beginning of the outbreak may explain introduction of fecal bacteria. In view of the unsolved problem of possible future contamination of springs in karst areas, the water department of this district authority has issued an order requesting installation of a permanent ultraviolet water-treatment facility.
