An E. coli outbreak centered in the Midwest has expanded to New York state, according to the Centers for Disease Control and Prevention.
The outbreak was previously reported in Indiana, Michigan, Ohio, and Pennsylvania. New York and Kentucky joined the list Friday with one case in each state.
The CDC has noted that the number of people sickened is likely higher than the 97 total reported in the six states, and the true number could include other states. Michigan is home to most of the affected - 58, the CDC said.
In a statement in August, the fast food chain said it was fully cooperating with public health authorities in the investigation and that it would be removing the sandwich lettuce at some restaurants in the region.
It's not clear if it will do so for restaurants in the additional states.
The company did not immediately respond to a request for comment Saturday evening.
Wendy has noted that its lettuce has not been confirmed as the source of the outbreak and said it uses a different lettuce in its salads, so that particular supply will remain.
Though no source has been identified, the CDC said roughly 8 in 10 people who reported their illness ate food from a Wendy's location within a week of symptoms appearing. A strong majority of those who could remember details about their orders said they had sandwiches or burgers that included romaine, the agency said.
Investigators were working to confirm the outbreak's source, the CDC said.
Depending on its form, E. coli can cause diarrhea, urinary tract infection, respiratory illness, pneumonia, and other illnesses, according to the CDC.
There is no specific treatment, and most people get over it naturally. Severe cases should prompt a visit to a physician, the agency said.
The CDC said 43 been hospitalized and 10 have developed hemolytic uremic syndrome, which can cause kidney failure. No deaths have been reported.
This article was originally published on NBCNews.com