The 0157 and H7 are taken from the laboratory designation that identifies the harmful strain of E. coli from harmless strains. E. coli comes from human and animal wastes. During heavy rain, E. coli may be washed into creeks, rivers, streams, lakes, or groundwater. One of the worst outbreaks occurred in 1997 in thousands of ground beef patties distributed by a Hudson Foods meat processing plant in Columbus, Nebraska. Although most infections have come from eating undercooked ground beef, new food sources such as leaf lettuce, alfalfa sprouts, and goat's milk have recently been identified.
More severe cases develop severe diarrhea and abdominal cramps.
Blood is often seen in the stool. Usually little or no fever is present. Symptoms usually appear about three days after exposure, with a possible range of one to nine days. Infections spread through contaminated water and by many food sources such as undercooked ground beef, unpasteurized milk and apple cider, ham, turkey, roast beef, sandwich meats, raw vegetables, cheese. Exposure to contaminated water in recreational swimming sites can also spread E.Coli.