Little information is available to the public in the U.S. or Canada more than six weeks into a deadly E. coli O157:H7 outbreak linked to romaine lettuce.

The risk is ongoing in both countries, officials report. Canadian officials are suggesting consumers in some provinces avoid all romaine lettuce. Government officials haven’t revealed any information about implicated suppliers, distributors or retailers in the romaine supply chain.

Almost 60 people are confirmed to have fallen ill, including one in Canada who died, since mid-November. Initially thought to be limited to certain provinces in Canada, 17 of the confirmed victims are in the U.S. They are spread across 13 states from coast to coast, according to a Dec. 28 statement from the the Centers for Disease Control and Prevention.

Whole genome sequencing shows E. coli O157:H7 samples from sick people in both countries are the same strain, which is evidence that a single source is likely, the CDC reports.

The 41 Canadian victims are from five provinces. More than 40 percent of them have been hospitalized. The health agency first reported the outbreak on Dec. 11. At that time Canadian officials identified romaine lettuce as the probable source.

Three days later those federal health officials reported the death, updated the number of confirmed cases, and said people in Eastern provinces should “consider consuming other types of lettuce, instead of romaine lettuce.”

That suggestion remained in place as of Dec. 28 when the Canadian health agency last updated its outbreak information.

“The outbreak appears to be ongoing, as illnesses linked to romaine lettuce continue to be reported to the Public Health Agency of Canada. These illnesses indicate that contaminated romaine lettuce may still be on the market, including in restaurants, grocery stores and any establishments that serve food,” the Dec. 28 updat reported.

“At this time, the investigation evidence suggests that there continues to be a risk of E. coli infections associated with the consumption of romaine lettuce.

The U.S. CDC acknowledged the Canadian warning and reported it’s investigators are considering leafy greens and romaine as a possible source. But the U.S. officials stopped short of recommending any changes for consumers.

“CDC is still collecting information to determine whether there is a food item in common among sick people, including leafy greens and romaine,” according to the CDC statement.

“Because we have not identified a source of the infections, CDC is unable to recommend whether U.S. residents should avoid a particular food. This investigation is ongoing, and more information will be released as it becomes available.

The U.S. Food and Drug Administration has not posted information about the outbreak or investigations. Federal food safety officials in Canada are assisting with the investigation.

“… the Canadian Food Inspection Agency is testing romaine lettuce for the presence of E. coli,” according to Canada’s public health statement. “At this time, no source of contamination has been identified. There is no evidence to suggest that provinces in western Canada are affected by this outbreak.”

Risks for consumers
Although anyone can get develop an E. coli infection from exposure to the pathogen, pregnant women, people with weakened immune systems, young children and older adults are most at risk for developing serious complications, public health officials warn.

“This is especially true for this outbreak strain of E. coli (O157:H7), which is more likely to cause severe illness than other E. coli strains,” Public Health Agency of Canada reported.

Laboratory testing is necessary to determine whether food is contaminated with E. coli because it can’t be seen, smelled or tasted.

“Romaine lettuce can have a shelf life of up to five weeks; therefore it is possible that contaminated romaine lettuce purchased over the past few weeks may still be in your home,” Canadian officials told consumers.

Advice to consumers
Anyone who has eaten romaine lettuce and developed symptoms of E. coli infection should immediately seek medical attention. Specific lab test are required to diagnose E. coli infection.

Symptoms can include nausea, vomiting, headache, mild fever, severe stomach cramps, and watery or bloody diarrhea. The onset of symptoms can range from 1 to 10 days after exposure.

“Some do not get sick at all, though they can still spread the infection to others. Others may feel as though they have a bad case of upset stomach. In some cases, individuals become seriously ill and must be hospitalized,” according to the health agency notice.

People who develop hemolytic uremic syndrome (HUS) need intensive medical treatment, usually including dialysis for kidney failure.