Infectious Disease Epidemiology & Prevention, Statens Serum Institut, Copenhagen, Denmark.
Department of Biostatistics & Epidemiology, Hudson College of Public Health, The University of Oklahoma Health Sciences Center, Oklahoma, United States.
Methods Mol Biol. 2021;2182:17-32. doi: 10.1007/978-1-0716-0791-6_3.
An outbreak is defined as the occurrence of disease cases in excess of normal expectancy within a particular area and a given time. Foodborne outbreaks caused by gastrointestinal bacteria such as Salmonella Typhimurium are among the most commonly reported and most extensively investigated. The classic outbreak investigation follows a series of well-defined steps which lead to a faster confirmation of the source and hopefully preventing of further cases. These steps are ideally undertaken using a One Health cross-sectorial collaboration approach involving partners from public health, food safety, and the veterinary and environmental sectors. In order to firmly identify the source of the outbreak, descriptive epidemiology is often combined with more robust evidence from analytical epidemiology such as a case-control study. A case-control study assesses whether a specific exposure is associated with illness, firstly by identifying cases (persons known to have been ill) and controls (persons who have not been ill, used as a reference group), and then retrospectively through interviews determining specific exposures for all persons. This information ultimately leads to the calculation of an odds ratio (see Note 3) which indicates the strength of the association between specific exposures and the outcome (illness or no illness). A well-conducted case-control study may substantiate or form core evidence as to the vehicle of a foodborne outbreak and is often a very important investigation tool, particularly in situations where microbiological proof cannot be obtained.
暴发是指在特定地区和特定时间内，疾病病例超过正常预期的发生。食源性暴发由胃肠道细菌引起，如鼠伤寒沙门氏菌，是最常报告和最广泛调查的暴发之一。经典的暴发调查遵循一系列明确的步骤，这些步骤可以更快地确认来源，并希望防止进一步的病例发生。这些步骤理想情况下是使用涉及公共卫生、食品安全以及兽医和环境部门的合作伙伴的跨部门“One Health”合作方法来完成。为了确定暴发的来源，描述性流行病学通常与更具说服力的分析性流行病学证据相结合，例如病例对照研究。病例对照研究通过识别病例（已知患病的人）和对照（未患病的人，用作参考组），然后通过访谈回顾性地确定所有人群的具体暴露情况，来评估特定暴露是否与疾病相关。该信息最终计算出比值比（见注 3），该比值比表示特定暴露与结果（患病或未患病）之间的关联强度。精心设计的病例对照研究可以证实或形成食源性暴发传播媒介的核心证据，并且通常是一种非常重要的调查工具，特别是在无法获得微生物证据的情况下。
