An outbreak of diarrhoeal disease attributed to Shigella sonnei

Abstract

SUMMARYAn 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.

Molecular Epidemiology of a Shigella flexneri Outbreak in a Mountainous Township in Taiwan, Republic of China

“…The disease is highly contagious due to its low infection dose (3). Epidemics usually occur in areas with crowding and poor sanitary conditions, where transmission from person to person is common, or when food or water is contaminated by the organism (5,9,15,17). In Taiwan, about 250 to 550 cases of shigellosis were identified annually during the years from 1995 to 1999, with an average annual incidence rate of 1 to 3 cases per 100,000 persons.…”

Incorporating Time–Dose–Response Into Shigella flexneri and Shigella sonnei Outbreak Models

“…The untreated pond water was stored in towers and piped to the school without treatment, and students reportedly drank from this source frequently. The S. sonnei case was modeled using a primary wave affecting 148 villagers in Crete, Greece (Samonis et al 1994). Illnesses were attributed to a spring water source contaminated with fecal coliforms from a nearby sewage facility.…”

“…Outbreak models. The outbreak model was next fit to two outbreak data sets: the primary spread of S. flexneri that originated from a school well in Sichuan Province and was investigated by He et al (2012) and the primary S. sonnei outbreak in a Crete village that was linked to contaminated spring water and was investigated by Samonis and colleagues (1994). Since the BPwE was the best‐fit model, this was the time‐dependency kinetic model that was used in the incubation distributions.…”

“…The mean values of the exposure distribution range from 2.85 to 23.74 days. Samonis et al (1994) were not able to determine a range of exposure times for the residents exposed to S. sonnei through contaminated drinking water. The first case occurred on December 11, and water chlorination and other environmental control measures were initiated on December 24, presumably ending the Shigella exposures.…”

Surveillance of waterborne disease in European member states: a qualitative study

“…Cryptosporidium (Guyonnet & Claudet 2002), Escherichia coli O157 (Dev et al 1991), Giardia (Gornik et al 2000), norovirus (Kukkula et al 1999) and Shigella (Samonis et al 1994). The early detection of outbreaks of infectious intestinal waterborne disease can reduce morbidity and mortality provided that appropriate steps are taken to identify and control the source.…”