Waterborne Shigellosis at a Public School

Abstract

In November 1972 an outbreak of gastrointestinal illness occurred at a public school in Stockport, Iowa. One hundred ninety-four (72%) of 269 pupils and 14 (16%) of 23 staff members were affected. The etiologic agent was a strain of Shigella sonnei resistant to multiple antimicrobials. Waterborne transmission of shigellosis was documented epidemiologically and by isolation of the organism from the school water system. Ninety-seven (14%) of 698 of the students' household contacts developed diarrhea, and possible secondary cases also occurred in 3 (9%) of 32 household contacts of school staff.

A community waterborne outbreak of gastro-enteritis attributed to Shigella sonnei

“…It is possible that a number of patients with mild symptoms did not contact any hospital. It is known that shigella infection can be present with mild or no symptoms [15,16]. We should also consider that a small number of patients would have contacted private physicians.…”

An outbreak of diarrhoeal disease attributed to Shigella sonnei

“…However, the organism was not isolated from water, including samples from the suspected fountain. This is not unusual in a waterborne outbreak [10,11,16]. Shigella is difficult to culture from water and may require samples of as much as 10 litres [6].…”

“…We believe that a significant number of villagers with mild symptoms did not contact the investigators' team, since the majority of patients were reluctant to seek medical care. For the same reason, asymptomatic patients were not examined, although shigella infection can be present with mild or no symptoms at all [10,11,17]. Hence, we believe that a number of asymptomatic villagers could have been infected by shigella and spread the organism in their households and contacts, especially at school.…”

“…Shigellosis is usually transmitted from person to person in households [5,6], however outbreaks due to contaminated food [7][8][9] or water [6,10] are not unusual. We report an outbreak of shigellosis in a Greek village on the island of Crete, which was linked to contaminated drinking water.…”

Shigellosis outbreak associated with swimming.

“…'-3 However, common source outbreaks due to contaminated food,' and water4 7 have been reported. Only rarely has Shigella been shown to be spread by swimming in contaminated water.…”