Romaine harvested outside these six California regions is not related to the current outbreak, according to the FDA, which is working with the US Centers for Disease Control and Prevention as well as state and local agencies in its investigation. Based on this information, the CDC has narrowed its warning to consumers: Romaine lettuce harvested from those six California counties should not be eaten. If you don't know where your romaine was grown, do not eat it.Romaine lettuce entering the market will be labeled with either a harvest location and date or hydroponic or greenhouse information, according to the FDA. If your romaine does not have this information, you should not eat it, the agency says.Forty-three people have been infected with the outbreak strain, including 16 who have been hospitalized, in 12 states since October, according to the FDA. People have become sick in California, Connecticut, Illinois, Massachusetts, Maryland, Michigan, New Hampshire, New Jersey, New York, Ohio, Rhode Island and Wisconsin. At least one of the hospitalized people developed hemolytic uremic syndrome, a potentially life-threatening form of kidney failure. No deaths have been reported.Symptoms of an E. coli infection, which usually begin about three or four days after consuming the bacteria, can include watery or bloody diarrhea, fever, abdominal cramps, nausea and vomiting, according to the CDC. Most people infected by the bacteria get better within five to seven days, though this particular strain of E. coli tends to cause more severe illness.The outbreak is not related to another multistate outbreak linked to romaine lettuce this summer.The Public Health Agency of Canada and the Canadian Food Inspection Agency are investigating a similar outbreak and coordinating with US public health authorities. Twenty-two people have become infected with E. coli illness in Ontario, Quebec and New Brunswick, Canadian health authorities reported as of November 23. Eight people, including one with hemolytic uremic syndrome, have been hospitalized. No deaths have been reported.