Department of Zoonoses, Food- and Waterborne Diseases, Norwegian Institute of Public Health, Oslo, Norway.
University of Oslo, Faculty of Medicine, Institute of Health and Society, Oslo, Norway.
Euro Surveill. 2020 Sep;25(35). doi: 10.2807/1560-7917.ES.2020.25.35.2000011.
On 6 June 2019, the Norwegian Institute of Public Health was notified of more than 50 cases of gastroenteritis in Askøy. A reservoir in a water supply system was suspected as the source of the outbreak because of the acute onset and geographical distribution of cases. We investigated the outbreak to confirm the source, extent of the outbreak and effect of control measures. A case was defined as a person in a household served by Water Supply System A (WSS-A) who had gastroenteritis for more than 24 h between 1 and 19 June 2019. We conducted pilot interviews, a telephone survey and an SMS-based cohort study of residents served by WSS-A. System information of WSS-A was collected. Whole genome sequencing on human and environmental isolates was performed. Among 6,108 individuals, 1,573 fulfilled the case definition. Residents served by the reservoir had a 4.6× higher risk of illness than others. isolated from cases (n = 24) and water samples (n = 4) had identical core genome MLST profiles. Contamination through cracks in the reservoir most probably occurred during heavy rainfall. Water supply systems are susceptible to contamination, particularly to certain weather conditions. This highlights the importance of water safety planning and risk-based surveillance to mitigate risks.
2019 年 6 月 6 日，挪威公共卫生研究所收到来自 Askøy 地区超过 50 例肠胃炎报告。由于发病急且病例呈地域性分布，因此怀疑供水系统中的蓄水池是此次暴发的源头。我们对此次暴发进行了调查，以确认源头、暴发范围和控制措施的效果。病例定义为 2019 年 6 月 1 日至 19 日期间，居住在由供水系统 A（WSS-A）供水的家庭中，出现肠胃炎症状超过 24 小时的人员。我们开展了试点访谈、电话调查和基于短信的 WSS-A 居民队列研究。收集了 WSS-A 的系统信息，并对人类和环境分离株进行了全基因组测序。在 6108 人中，有 1573 人符合病例定义。与其他人群相比，来自蓄水池的居民患病风险高 4.6 倍。从病例（n=24）和水样（n=4）中分离出的菌株具有相同的核心基因组 MLST 图谱。最有可能是在强降雨期间通过蓄水池裂缝发生了污染。供水系统容易受到污染，特别是在某些天气条件下。这突显了进行水安全规划和基于风险的监测来降低风险的重要性。
