| Popis: |
The first outbreak of hemorrhagic colitis due to Escherichia coli 0157:H7 in Canada occurred in 1982. There were 31 cases with one death in a home for the aged; undercooked hamburger was the suspected vehicle. The serotype 0157 :H7 had rarely been encountered prior to 1982, but since then, sporadic and outbreak cases of hemorrhagic colitis and its complication, hemolytic uremic syndrome, have steadily increased. In Canada, the most severe of all outbreaks, with a case fatality rate of 31%, occurred in a nursing home in 1985. In 1987, 315 cases in eight outbreaks were reported. At least six outbreaks of hemorrhagic colitis in North America have been linked to ingestion of undercooked beef and one to raw milk. E. coli 0157:H7 has been isolated from market samples of beef, pork, poultry and lamb, feces of healthy heifers and calves, and raw milk. Although E. coli 0157:H7 has been responsible for outbreaks of hemorrhagic colitis, other serotypes have also been implicated in sporadic cases, especially in children with hemolytic uremic syndrome. All isolates produce high levels of cytotoxin(s) affecting Vero cells (verotoxin). Since food of animal origin is the primary source of infection in humans, careful handling and adequate cooking of all raw meats is required to minimize or eliminate the risk of infection with E. coli 0157:H7 and other verotoxin-producing serotypes. |
