Diarrhoea in close contacts as a risk factor for childhood haemolytic uraemic syndrome. The CPKDRC co-investigators.

To determine whether the risk factors for childhood haemolytic uraemic syndrome (HUS) are similar to risk factors previously reported for Escherichia coli O 157. H7 gastroenteritis, we conducted a case-control study at eight paediatric hospitals in the summer of 1990. Thirty-four consecutive children with HUS were prospectively enrolled; all had diarrhoea and 88% had laboratory evidence of exposure to verotoxin-producing E. coli (VTEC). The 102 controls were otherwise healthy children with minor acute injuries. Parents of all subjects responded to a questionnaire about each child's exposure to various foods, methods of food preparation, sources of water, travel, and individuals with diarrhoea. Children with HUS were significantly more likely than controls to have had close contact with an individual with diarrhoea in the 2 weeks before the onset of illness (74 v. 29%, P < 0.00001; odds ratio 7.0, 95% CI 2.7-18.5). The onset of diarrhoea in the contacts occurred a median of 6 days (range, 1- > 14 days) before the onset of diarrhoea in the HUS patients. Exposure to undercooked ground meat was not significantly more common in the patients with HUS (15 v. 8%; P = 0.05). These data provide evidence consistent with person-to-person transmission of VTEC in a substantial proportion of episodes of childhood HUS.