An outbreak of diarrhoeal disease attributed to Shigella sonnei

An outbreak of gastroenteritis occurred in a village on the Island of Crete, with 1479 inhabitants. One hundred and thirty-eight symptomatic patients from 57 different families were examined. Thirty percent of children under 12 years were affected compared with 4% of adolescents and adults (P < 0.0001). Thirty-five out of 105 stool cultures (33%) grew Shigella sonnei. Thirty-four isolates had the same susceptibility pattern and were sensitive to ampicillin, while one was resistant to this antibiotic. Thirty-three isolates had the same plasmid profile. Based on epidemiologic and environmental findings, it was concluded that the transmission of shigellosis was waterborne. Shigella were not isolated from water, but one of the three village springs was found to be contaminated with faecal coliforms. This spring was probably contaminated by sewage material, due to its proximity to a source of untreated sewage effluent. Implementation of environmental and control measures brought the epidemic to an end.