McDonald’s shares fell after the CDC said an E. coli outbreak was linked to Quarter Pounders

McDonald’s Shares dropped in full trade Friday after the Centers for Disease Control and Prevention said an E. coli outbreak linked to McDonald’s Quarter Pounder burgers has led to 10 hospitalizations and one death.

The agency said 49 cases have been reported so far in 10 states from Sept. 27 to Oct. 11, with most of the illnesses in Colorado and Nebraska. “Most” people who got sick reported eating a McDonald’s Quarter Pounder, the CDC added.

One patient had hemolytic uremic syndrome, a serious condition that can lead to kidney failure. An old man in Colorado died.

The CDC says the number of people affected by the outbreak is “likely higher” than has been reported so far. The agency says that’s because many people recover from E. coli infections without trying or receiving medical treatment. It also typically takes three to four weeks to determine whether a patient’s illness is part of an outbreak, the CDC added.

Investigators​​​​are working to determine what ingredients may have been contaminated, and McDonald’s has recalled the ingredients for the burgers, the CDC said. The agency said preliminary information from the Food and Drug Administration indicated that onions may be the source of the outbreak.

Quarter Pounder Hamburgers will be temporarily unavailable in some states, but the CDC did not specify which ones.

McDonald’s shares fell about 9% in after-hours trading Tuesday.

E. coli refers to a group of bacteria found in the intestines of almost all people and animals. But some strains of bacteria can cause mild to severe illness if people eat contaminated food or drink contaminated water.

Symptoms, including stomach cramps, diarrhea and vomiting, usually begin three to four days after ingesting the bacteria, according to the CDC. Most people recover without treatment after five to seven days.

This is new news. Please refresh for updates.