Epidemic Escherichia coli O157:H7 gastroenteritis and hemolytic-uremic syndrome in a Canadian inuit community: intestinal illness in family members as a risk factor.

OBJECTIVE

To evaluate risk factors for childhood hemolytic-uremic syndrome (HUS) and gastroenteritis during an epidemic of Escherichia coli O157:H7 infection.

DESIGN

Case-control study.

SETTING

Remote Inuit community of Arviat in northern Canada.

PARTICIPANTS

Of the 565 Arviat residents less than 15 years of age, 19 had HUS and 65 more had E. coli O157:H7 gastroenteritis. The 19 children with HUS were compared with 19 age- and gender-matched children with uncomplicated E. coli O157:H7 gastroenteritis, and both HUS and gastroenteritis patients were compared with 19 healthy control subjects.

INTERVENTIONS

Questionnaire administered face-to-face to parents of participants in the home.

MAIN OUTCOME MEASURES

Rates of exposure to foods, travel, sources of water, and gastrointestinal illness in family members.

RESULTS

Patients with HUS and those with uncomplicated E. coli O157:H7 gastroenteritis differed only on measures of clinical severity. In the 7 days before the onset of gastrointestinal symptoms, children with HUS and those with uncomplicated gastroenteritis were more likely to have been exposed to a family member with diarrhea than were the healthy control subjects (odds ratio = 9 for HUS vs healthy control subjects; 95% confidence interval 2 to 43; p < 0.01). Undercooked ground meat and foods traditionally consumed by the Inuit were not implicated as risk factors in E. coli O157:H7 infection.

CONCLUSIONS

These findings emphasize the potential for extensive intrafamilial transmission of verotoxin-producing E. coli once infection is introduced into certain communities.