A 10-state E. coli outbreak linked to McDonald’s Quarter Pounder hamburgers has killed one person in Colorado and sickened at least 26 others in the state, the Centers for Disease Control and Prevention announced Tuesday. The CDC reported 49 people have gotten sick nationwide and 10 needed hospital care, including one child who suffered severe kidney complications. All of the people sickened reported eating at McDonald’s, and “most” said they ate Quarter Pounders, the federal health agency said. The Colorado Department of Public Health and Environment said the person who died was “older” and had underlying health conditions, but did not identify the victim. Neither state nor federal officials specified which McDonald’s restaurants in Colorado served the people sickened with E. coli. People over 65 and children younger than five are at higher risk of severe illness from E. coli, a type of bacteria which causes vomiting, severe stomach cramps and diarrhea, often with blood. Most people recover without treatment, but some develop severe dehydration or kidney damage. In addition to Colorado, McDonald’s diners also reported getting sick between Sept. 27 and Oct. 11 in Oregon, Montana, Utah, Wyoming, Nebraska, Kansas, Iowa, Missouri and Wisconsin. Colorado has the most cases, 26, followed by Nebraska with nine. “This outbreak may not be limited to the states with known illnesses, and the true number of sick people is likely much higher than the number reported,” CDC officials said on the agency’s outbreak page. “This is because many people recover without medical care and are not tested for E. coli.” The state health department said the U.S. Food and Drug Administration believes “fresh-slivered onions” used on Quarter Pounders — and not any other McDonald’s menu items — may be the culprit, though the U.S. Department of Agriculture is still investigating whether beef patties could be the source of the outbreak. McDonalds’s, in a statement posted to the fast-food chain’s corporate website, said “a subset of illnesses may be linked to slivered onions used in the Quarter Pounder and sourced by a single supplier that serves three distribution centers.” In a statement, Cesar Piña, McDonald’s chief supply chain officer for North America, said the company has gotten rid of onions from the supplier to the affected areas, and temporarily took the Quarter Pounder off the menu in Colorado and the other states where customers got sick, in addition to parts of New Mexico, Nevada, Oklahoma and Idaho. The company is working with the CDC to safely reintroduce all items, he said. “We are working in close partnership with our suppliers to replenish supply for the Quarter Pounder in the coming weeks (timing will vary by local market),” he said in a statement. “In the meantime, all other menu items, including other beef products (including the cheeseburger, hamburger, Big Mac, McDouble and the double cheeseburger) are unaffected and available.” Related Articles Health | This organization has effectively eliminated agricultural worker abuse. Will Colorado farmers join the cause? Health | Tim Walz raises $3 million in Denver, capping “interesting” first week as Kamala Harris’ VP pick The type of bacteria implicated in this outbreak, E. coli O157:H7, causes about 74,000 infections in the U.S. each year, leading to more than 2,000 hospitalizations and 61 deaths. Infections are especially dangerous for children younger than 5 and can cause acute kidney failure. The state health department asked people experiencing symptoms of E. coli who had recently eaten at McDonald’s to call a doctor and their local public health department. Symptoms typically appear three to four days after eating contaminated food, but can take up to 10 days to develop. If you think you could have E. coli or another foodborne illness, wash your hands frequently to avoid passing the infection to others, and don’t prepare food for anyone else, the state health department said in a news release. The Associated Press contributed to this report. Sign up for our weekly newsletter to get health news sent straight to your inbox. Updated 5:20 p.m. Oct. 22, 2024: This story has been updated to correct the number of people sickened in Colorado after federal officials initially misreported that figure.