E. coli outbreak linked to fall fair

It appears that autumn poses special risks for infection by verotoxin-producing Escherichia coli (VTEC), the Canadian Food Inspection Agency (CFIA) and a health unit in London, Ont., report.

Last fall the Middlesex-London Health Unit reported 159 suspected cases of E. coli O157:H7 infection that were linked to an agriculture pavilion at the Western Fair. The investigators found "very strong evidence" linking the outbreak to sheep and goats at the fair's petting zoo. VTEC, commonly found in the intestines of healthy cattle, is transmitted to humans by fecaloral contact. One 9-year-old London boy was hospitalized with hemolytic uremic syndrome (HUS). Another infected child attended a day-care centre, prompting the health unit to remove temporarily all children who had diarrhea. Children and elderly persons are especially vulnerable to VTEC infection.

Southwestern Ontario is no stranger to the bacterium. A 1985 outbreak in London, which was traced to sandwiches containing uncooked meat or poultry, killed 19 nursing-home residents. Soon after, another outbreak in nearby Sarnia affected children who had consumed unpasteurized milk during a school visit to a dairy farm. Last fall, at least 116 people attending a fall fair near Albany, NY, were also affected. Eleven of the children involved developed HUS, and a 3-year-old girl and 79-year-old man died. The problem was traced to high levels of E. coli O157:H7 found in unchlorinated water from a shallow well that had been used by some of the fair's food vendors.

In October, the CFIA warned about the risk of VTEC infection from unpasteurized fruit juice or cider. The problem may arise when cider is made from dropped apples contaminated by grazing cattle. In 1998 at least 6 people in Ontario's Perth County were infected with VTEC after consuming cider from a 264-L batch produced by 2 farm families and shared with friends and relatives.