Escherichia coli O157 : H7; an economic assessment of an outbreak

Background The aim of the study was to assess the impact of an outbreak of Escherichia coli O157:H7 that occurred in 1994 in a rural community, with a population of approximately 107 000, to the west of Edinburgh. Methods The impact of the outbreak was assessed during the acute phase of t he illness and in the subsequent 12 months. The method involved three surve ys of confirmed cases using general practice notes, hospital records and in terviews with cases. Key persons involved in the investigation and control of the outbreak were also interviewed. The impact of the illness on cases a nd their families was estimated and the resources used to treat cases and t o control the outbreak were costed and long-term costs projected. Results There were 71 cases whose ages ranged from 7 months to 84 years. Th e mortality rate was 1.4 per hundred cases. There were 10 cases of haemolyt ic uraemic syndrome (HUS) and one case of thrombotic thrombocytopenia purpu rpa (TTP). Two children were on long-term dialysis. Co-morbidity involving the immune system was associated with hospital admission. The illness laste d on average 6.9 weeks. Twenty-six per cent of cases reported symptoms 12 m onths later. The average cost per HUS case was pound 62 353, the TTP case c ost pound 21 422, non-HUS and non-TTP cases cost pound 1030. The costs of i nvestigating and controlling the outbreak were pound 171 848. The costs of cases projected over 30 years were pound 11.9 million, or pound 168 032 per case. Conclusions The impact on the health of cases was considerable and the cost s were high. Every effort should be made to prevent the disease and to iden tify and control outbreaks quickly.