Epidemiological investigation of the Central Scotland outbreak of Escherichia coli 0157 infection, November to December 1996

On Friday, 22 November 1996, the microbiologist at a hospital in Lanarkshir e, Scotland, identified presumptive Escherichia coli O157 in faecal specime ns submitted by three patients with bloody diarrhoea, and confirmed its pre sence in one. Over the next 6 h, 12 more potential cases were identified. I nvestigations first indicated then confirmed a single food premises as the source of infection. Effective control measures were applied promptly. The outbreak was declared over on 20 January 1997, by which time 512 cases had been identified, and infection with the outbreak strain confirmed in 279. T wenty deaths occurred in cases during the outbreak and there were two more in cases during 1997. Seventeen of these deaths resulted from the outbreak. This paper describes the outbreak's epidemiological investigation, referri ng to other investigations, and control measures, where appropriate.