A multi-state E-coli outbreak linked to McDonald's quarter-pounder hamburgers has affected dozens of people and claimed at least one life, the U.S. Centers for Disease Control and Prevention (CDC) reported.

E-coli is a bacteria that causes diarrheal illness in people typically through contaminated food or water. Although mild in most cases, it can cause severe infection in young children, people with weakened immunity, and elderly adults.

The current outbreak, reported across 10 states, has been linked to the E. coli O157 strain. According to reports, 49 people developed symptoms of E-coli infection between September 27, 2024, and October 11, 2024. However, the actual number is expected to be higher than reported. This is because in many cases, patients may recover from mild illness without medical attention and the current cases may take 3-4 weeks to be reported as part of the outbreak.

"Of 28 people with information available, 10 have been hospitalized, and 1 person developed hemolytic uremic syndrome (HUS), a serious condition that can cause kidney failure. One death has been reported from an older adult in Colorado. This is not the same person with HUS," the CDC said in a news release.

Investigators are now working to identify the contaminated ingredient in the hamburger tied to the illness. Meanwhile, McDonald's has stopped using fresh slivered onions and quarter-pound beef patties in several states and halted the sale of quarter-pounders in certain locations.

"Preliminary traceback and distribution information reviewed by FDA shows that slivered onions served on Quarter Pounders are a likely source of contamination. FDA is working quickly to confirm that these onions are a source of this outbreak and to determine if these onions were served or sold at other businesses," the news release stated.

Officials are urging the public to contact their healthcare provider if they experience E. coli symptoms after eating a McDonald's Quarter Pounder hamburger.

The symptoms of E-coli infection include diarrhea, especially if accompanied by a high fever or lasting more than three days, and bloody diarrhea. Other signs to watch out for are severe vomiting and signs of dehydration such as dizziness, infrequent urination, dry mouth and throat.

The symptoms typically begin 3 to 4 days after the bacteria enters the body and most people recover within a week without treatment. However, hospitalization may be required for those with severe symptoms and complications such as HUS.

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