At least 58 people in the United States and Canada have become ill due to a "dangerous strain" of E. coli, likely from eating romaine lettuce, according to Consumer Reports.

Seventeen incidents have been reported in California, Illinois, Connecticut, Indiana, Michigan, Nebraska, New Hampshire, New York, Ohio, Virginia, Pennsylvania, Vermont and Washington from November 15 through December 8, 2017. USA officials have yet to determine that the outbreak has to do with any specific food. There's also been one reported death in Canada. Officials in Canada have identified romaine lettuce as the source of the outbreak in that country, but USA officials say they still don't have enough information to name a food source involved in the American outbreak.

Another possibility is that the E. coli strain causing illness in the United States is actually slightly different from the strain in Canada. Two of the hospitalized patients developed hemolytic uremic syndrome, a type of kidney failure.

Ian Williams, PhD, chief of the CDC's Outbreak Response and Prevention Branch, told CIDRAP News that the last illness onset was Dec 8, and though cases are still being reported, the pace of new reports appears to be slowing.

In the meantime, Consumer Reports experts have cautioned consumers to avoid romaine lettuce until the source of the outbreak has been uncovered. "They can say it's romaine lettuce, but they cannot say what lettuce and from where", he said.

A similar outbreak in Canada was traced to romaine lettuce.

In the USA, government health officials are investigating the outbreaks, but have stopped short of recommending people avoid romaine lettuce or any other food. Young children, the elderly and anyone with a condition that weakens the immune system are at a greater risk for illness. It's possible that a single source of contamination - such as a contaminated water supply - could affect different food products, Chapman said.

"This time of year, most of our lettuce will come from southern places ... so if it's affecting both countries, it may be from California or Mexico or other countries that produce romaine lettuce", said Schellhorn.

While washing any greens may help avoid some illnesses, Consumer Reports warns that it may not get rid of all E. coli bacteria that may be present.