Fifty-four Rotterdam patients in which a primary infection with Campylobacter jejuni had been detected (index patients) were compared with 54 control subjects with regard to the consumption and preparation of foods 7 days before onset of illness and the keeping of pet animals. Significantly more index patients than controls had eaten chicken meat (47 v. 29; P = 0·0002), particularly at barbecues (14 v. 2; P = 0·0015). Marginally more index patients had eaten pork (47 v. 39; P = 0·048) or inadequately heated meat (13 v. 8), though in the last case numbers were too small to be statistically significant. The consumption of beef or mutton and outdoor eating (other than at barbecues) were essentially the same in both groups. There was no significant association with the keeping of pet animals, although a few more index patients had cage birds than controls (18 v. 12).
Twenty-one (15%) of 130 household contacts of index patients also suffered from diarrhoea during the same period. Circumstantial evidence pointed to a common source of infection with the index patient in 13 instances (nine households) and probable intrafamilial spread of infection in six instances.
Campylobacters were isolated from one of 110 swabs of kitchen work surfaces and eight of 107 swabs taken from lavatory bowls in index households.