title: How is the source of food poisoning outbreaks established? The example of three consecutive Salmonella enteritidis PT4 outbreaks linked to eggs.
abstract: Three consecutive outbreaks of Salmonella enteritidis PT4 occurred in Wales in 1989 in which epidemiological and microbiological investigation established eggs as the likely source although kitchen inspection and food preparation histories suggested other vehicles of infection. This paper examines the contribution of analytical epidemiology in attributing causation, with particular reference to those limitations which are regarded as inherent in epidemiological evidence. Such evidence, implicating eggs in the three outbreaks, fulfilled 6/7 widely accepted criteria for causation; data to assess the seventh were lacking. Collaboration between different agencies and professionals in investigating outbreaks is very important.
authors.affiliation: PHLS Communicable Disease Surveillance Centre (Welsh Unit), Cardiff, United Kingdom.
authors.forename: R L
authors.initials: RL
authors.lastname: Salmon
authors.forename: S R
authors.initials: SR
authors.lastname: Palmer
authors.forename: C D
authors.initials: CD
authors.lastname: Ribeiro
authors.forename: P
authors.initials: P
authors.lastname: Hutchings
authors.forename: T J
authors.initials: TJ
authors.lastname: Coleman
authors.forename: F J
authors.initials: FJ
authors.lastname: Willis
authors.forename: T N
authors.initials: TN
authors.lastname: Allsup
authors.forename: W N
authors.initials: WN
authors.lastname: Ritchie
mesh_terms: D004196:Disease Outbreaks; D004531:Eggs; D005516:Food Microbiology; D006801:Humans; D012478:Salmonella Food Poisoning / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology; D012477:Salmonella enteritidis / Q000302:isolation & purification*; D014852:Wales / Q000453:epidemiology