Godoy P, Borrull C, Palà M, Caubet I, Bach P, Nuín C, Espinet L, Torres J, Mirada G
Delegación Territorial del Departamento de Sanidad y Seguridad Social de Lleida. Facultad de Medicina. Universidad de Lleida, Spain.
Gac Sanit. 2003 May-Jun;17(3):204-9. doi: 10.1016/s0213-9111(03)71729-4.
The chlorination of public water supplies has led researchers to largely discard drinking water as a potential source of gastroenteritis outbreaks. The aim of this study was to investigate an outbreak of waterborne disease associated with drinking water from public supplies.
A historical cohort study was carried out following notification of a gastroenteritis outbreak in Baqueira (Valle de Arán, Spain). We used systematic sampling to select 87 individuals staying at hotels and 67 staying in apartments in the target area. Information was gathered on four factors (consumption of water from the public water supply, sandwiches, water and food in the ski resorts) as well as on symptoms. We assessed residual chlorine in drinking water, analyzed samples of drinking water, and studied stool cultures from 4 patients. The risk associated with each water source and food type was assessed by means of relative risk (RR) and 95% confidence intervals (CI).
The overall attack rate was 51.0% (76/149). The main symptoms were diarrhea 87.5%, abdominal pain 80.0%, nausea 50.7%, vomiting 30.3%, and fever 27.0%. The only factor associated with a statistically significant risk of disease was consumption of drinking water (RR = 11.0; 95% CI, 1.6-74.7). No residual chlorine was detected in the drinking water, which was judged acceptable. A problem associated with the location of the chlorinator was observed and corrected. We also recommended an increase in chlorine levels, which was followed by a reduction in the number of cases. The results of stool cultures of the four patients were negative for enterobacteria.
This study highlights the potential importance of waterborne outbreaks of gastroenteritis transmitted through drinking water considered acceptable and suggests the need to improve microbiological research into these outbreaks (viruses and protozoa detection).
公共供水系统的氯化处理使研究人员基本不再将饮用水视为肠胃炎暴发的潜在源头。本研究的目的是调查一起与公共供水系统的饮用水相关的水源性疾病暴发事件。
在西班牙巴凯拉（阿兰谷）通报一起肠胃炎暴发事件后，开展了一项历史性队列研究。我们采用系统抽样方法，从目标区域选取了87名入住酒店的人员和67名入住公寓的人员。收集了关于四个因素（公共供水系统的水、三明治、滑雪胜地的水和食物）以及症状的信息。我们评估了饮用水中的余氯，分析了饮用水样本，并研究了4名患者的粪便培养物。通过相对风险（RR）和95%置信区间（CI）评估了与每种水源和食物类型相关的风险。
总体发病率为51.0%（76/149）。主要症状为腹泻87.5%、腹痛80.0%、恶心50.7%、呕吐30.3%和发热27.0%。与疾病风险具有统计学显著关联的唯一因素是饮用水的消费（RR = 11.0；95% CI，1.6 - 74.7）。在饮用水中未检测到余氯，判定其可接受。观察到并纠正了与加氯器位置相关的问题。我们还建议提高氯含量，随后病例数有所减少。4名患者的粪便培养结果显示肠杆菌呈阴性。
本研究凸显了通过被认为可接受的饮用水传播的水源性肠胃炎暴发的潜在重要性，并表明有必要改进对这些暴发事件的微生物学研究（检测病毒和原生动物）。
