Zlot Amy, Simckes Maayan, Vines Jennifer, Reynolds Laura, Sullivan Amy, Scott Agdalena Kendall, McLuckie J Michael, Kromer Dan, Hill Vincent R, Yoder Jonathan S, Hlavsa Michele C
MMWR Morb Mortal Wkly Rep. 2015 May 15;64(18):485-90.
In July 2014, Multnomah County public health officials investigated a norovirus outbreak among persons visiting Blue Lake Regional Park in Oregon. During the weekend of the reported illnesses (Friday, July 11-Sunday, July 13) approximately 15,400 persons visited the park. The investigation identified 65 probable and five laboratory-confirmed cases of norovirus infection (70 total cases). No hospitalizations or deaths were reported. Analyses from a retrospective cohort study revealed that swimming at Blue Lake during July 12-13 was significantly associated with illness during July 13-14 (adjusted relative risk = 2.3; 95% confidence interval [CI] = 1.1-64.9). Persons who swam were more than twice as likely to become ill compared with those who did not swim in the lake. To control the outbreak, Blue Lake was closed for 10 days to prevent further illness. This investigation underscores the need for guidance for determining when to reopen untreated recreational water venues (e.g., lakes) associated with outbreaks, and communication tools to inform the public about the risks associated with swimming in untreated recreational water venues and measures that can prevent illness.
2014年7月，马尔特诺马县公共卫生官员对俄勒冈州蓝湖地区公园游客中发生的诺如病毒疫情展开调查。在报告发病的那个周末（7月11日星期五至7月13日星期日），约15400人到访该公园。调查确认了65例可能感染及5例实验室确诊的诺如病毒感染病例（共70例）。未报告有住院或死亡情况。一项回顾性队列研究的分析显示，7月12 - 13日在蓝湖游泳与7月13 - 14日发病显著相关（调整后相对风险 = 2.3；95%置信区间[CI] = 1.1 - 64.9）。游泳者患病的可能性是未在湖中游泳者的两倍多。为控制疫情，蓝湖关闭了10天以防止病情进一步蔓延。此次调查凸显了制定相关指南以确定与疫情相关的未处理过的娱乐用水场所（如湖泊）何时重新开放的必要性，以及需要有沟通工具来告知公众在未处理过的娱乐用水场所游泳的相关风险和可预防疾病的措施。
