Table 1.
Characteristics of outbreaks by year in which outbreak started*, North East England, 2012–2014
| Characteristic | 2012 | 2013 | 2014 | Total (2012–2014) |
|---|---|---|---|---|
| Total no. outbreaks | 12 (100%) | 9 (100%) | 25 (100%) | 46 (100%) |
| Setting† | ||||
| Care home | 12 (100%) | 8 (89%) | 18 (72%) | 38 (83%) |
| Food outlet | 0 | 0 | 4 (16%) | 4 (9%) |
| Private caterer | 0 | 1 (12%) | 3 (12%) | 4 (9%) |
| Symptoms | ||||
| Diarrhoea only | 6 (50%) | 4 (45%) | 16 (64%) | 26 (57%) |
| Diarrhoea and vomiting | 6 (50%) | 5 (56%) | 9 (36%) | 20 (43%) |
| Associated illness | ||||
| Total cases‡ | 176 (100%) | 102 (100%) | 384 (100%) | 662 (100%) |
| Median no. per outbreak (IQR) | 16 (10–19) | 11 (9–16) | 12 (9–15) | 13 (9–18) |
| Median attack rate (IQR)§ | 21 (15–24) | 12 (10–14)) | 15 (10–33) | 15 (11–23) |
| No. cases hospitalized | 7 (4%) | 0 | 1 (0·3%) | 8 (1%) |
| No. deaths | 3 (2%) | 0 | 1 (0·3%) | 4 (0·6%) |
IQR, Interquartile range.
*
Defined as the date of onset of illness in the first case at the time of reporting.
† Care home defined as a residential or nursing home for elderly or mentally infirm individuals. Food outlet defined as a premise at which food is regularly served, e.g. restaurant/pub/takeaway/mobile food van. Private caterer as an individual or business providing food on an ad hoc basis at an external event, e.g. wedding/festival.
‡ Defined on the basis of clinical symptoms.
§ Median attack rate only calculated for those outbreaks in which there was a clearly defined population at risk (n = 43).