On Monday, the U.S. Centers for Disease Control and Prevention (CDC) announced that at least five more people have become sick after eating at Chipotle Mexican Grill restaurants.

The victims--who are believed to have consumed food that was contaminated with E. coli STEC O26--ate at two specific Chipotle locations in Kansas and Oklahoma. It is not yet known what specific food item contained the bacteria.

Chipotle said previously that they expected more victims to come forward, perhaps because many food poisoning victims do not exhibit symptoms right away. Others might choose not to see a doctor right away.

Ian Williams from the CDC’s chief outbreak response and prevention branch says, “One of the challenges here has been that we have been able to identify the restaurants where people ate, but because of the way Chipotle does its record-keeping, we have been unable to figure out what food is in common across all those restaurants,”

Williams has also said that the DNA of the bacteria does not appear to be the same as in Chipotle’s previous rash of Shiga toxin-producing E. coli outbreaks. Still, he says that both types detected are rare.

This latest outbreak is Chipotle’s fifth since August.