Rumble C, Addiman S, Balasegaram S, Chima K, Ready D, Heard J, Alexander E
Field Epidemiology Service South East and London, Public Health England, 151 Buckingham Palace Road, London, SW1W 9SZ, UK.
North East and North Central London Health Protection Team, Public Health England, Ground Floor, South Wing, Fleetbank House, 2-6 Salisbury Square, London, EC4Y 8JX, UK.
J Food Prot. 2017 Feb;80(2):257-264. doi: 10.4315/0362-028X.JFP-16-083.
Outbreaks caused by norovirus infection are common and occur throughout the year. Outbreaks can be related to food outlets either through a contaminated food source or an infected food handler. Both asymptomatic and symptomatic food handlers are potentially implicated in outbreaks, but evidence of transmission is limited. To understand potential food handler transmission in outbreak scenarios, epidemiological and microbiological data on possible and confirmed norovirus outbreaks reported in London and South East England in a 2-year period were reviewed. One hundred eighty-six outbreaks were associated with a food outlet or registered caterer in this period. These occurred throughout the year with peaks in quarter 1 of study years. A case series of 17 outbreaks investigated by the local field epidemiological service were evaluated further, representing more than 606 cases. In five outbreaks, symptomatic food handlers were tested and found positive for norovirus. In four outbreaks, symptomatic food handlers were not tested. Asymptomatic food handlers were tested in three outbreaks but positive for norovirus in one only. Environmental sampling did not identify the causative agent conclusively in any of the outbreaks included in this analysis. Food sampling identified norovirus in one outbreak. Recommendations from this study include for outbreak investigations to encourage testing of symptomatic food handlers and for food and environmental samples to be taken as soon as possible. In addition, sampling of asymptomatic food handlers should be considered when possible. However, in light of the complexity in conclusively identifying a source of infection, general measures to improve hand hygiene are recommended, with specific education among food handlers about the potential for foodborne pathogen transmission during asymptomatic infection, as well as reinforcing the importance of self-exclusion from food handling activities when symptomatic.
诺如病毒感染引发的疫情很常见，且全年都会发生。疫情可能通过受污染的食物来源或受感染的食品从业人员与食品销售点相关联。无症状和有症状的食品从业人员都可能与疫情有关，但传播证据有限。为了解疫情场景中食品从业人员的潜在传播情况，我们回顾了伦敦和英格兰东南部在两年期间报告的可能和确诊的诺如病毒疫情的流行病学和微生物学数据。在此期间，186起疫情与食品销售点或注册餐饮服务商有关。这些疫情全年都有发生，在研究年份的第一季度达到高峰。对当地现场流行病学服务部门调查的17起疫情的病例系列进行了进一步评估，涉及606多例病例。在5起疫情中，对有症状的食品从业人员进行了检测，结果发现诺如病毒呈阳性。在4起疫情中，未对有症状的食品从业人员进行检测。在3起疫情中对无症状的食品从业人员进行了检测，但只有1人诺如病毒呈阳性。在本分析纳入的任何一起疫情中，环境采样均未最终确定病原体。食品采样在1起疫情中发现了诺如病毒。本研究的建议包括在疫情调查中鼓励对有症状的食品从业人员进行检测，并尽快采集食品和环境样本。此外，应尽可能考虑对无症状食品从业人员进行采样。然而，鉴于最终确定感染源的复杂性，建议采取一般措施改善手部卫生，对食品从业人员进行关于无症状感染期间食源性病原体传播可能性的特定教育，并强化有症状时自我排除食品处理活动的重要性。
