The U.S. Centers for Disease Control and Prevention (CDC) said on Friday that three additional states reported E. coli infections of the same strain as the Chipotle outbreak, sending shares in the chain down more than 9 percent.
The new outbreak reports came from California, Ohio and New York, the CDC said, bringing to six the number of states affected. The outbreak started in Washington state and Oregon before appearing in Minnesota this week.
The CDC earlier this week reported one Minnesota case with the same DNA fingerprint as the others, but it was not linked to the popular burrito chain.
In its update on Friday, the CDC reported that a second person in Minnesota who ate at Chipotle became ill with E. coli.
The CDC said 45 people have gotten food poisoning from the E. coli O26 outbreak strain, and of those, 43 had reported eating at Chipotle.
Public health investigators first identified E. coli O26 infections in people who had eaten at Chipotle restaurants around Seattle and Portland, Oregon. Chipotle recently reopened 43 restaurants in those areas after deep cleaning the eateries and replacing food.
Shares in Chipotle fell 9.4 percent to $554.93 after the CDC announcement.