Washington: One person has died and dozens have fallen ill following a severe E. coli outbreak linked to McDonald's Quarter Pounder hamburgers, according to the US Centers for Disease Control and Prevention (CDC).

The outbreak, which began in late September, spans ten western states, with most of the 49 reported cases concentrated in Colorado and Nebraska, the health agency stated.

What is E. coli bacteria?

E. coli bacteria are found in the guts of animals and in the environment. Infections can cause severe illness, including fever, stomach cramps, and bloody diarrhea.

Symptoms typically begin three to four days after exposure, and most individuals recover within five to seven days without treatment. However, some cases can become severe and may require hospitalization.

What has happened so far?

Shares of the fast-food chain dropped more than six percent in after-hours trading following the announcement.

Ten people have been hospitalized, including one child with hemolytic uremic syndrome—a serious condition that damages blood vessels in the kidneys.

"One older person in Colorado has died," the CDC stated.

All affected individuals carried the same strain of E. coli and reported eating at McDonald's before developing their symptoms, with most specifically recalling having consumed Quarter Pounders.

While investigators have not yet pinpointed the exact ingredient causing the outbreak, they are focusing on slivered onions and beef patties—both of which have been removed from restaurants in the affected states pending further investigation.

"Food safety is very important to me and everyone at McDonald's," said Joe Erlinger, president of McDonald's USA, in a video message. "We've taken steps to proactively remove slivered onions, which are used in Quarter Pounders, in select states.

"We've also made the decision to temporarily remove the Quarter Pounder from restaurants in affected areas."

He added that the majority of states are not affected and that other menu items, including other beef products, remain available in those areas.

The agency advised anyone who consumed a Quarter Pounder and developed symptoms of E. coli poisoning—such as diarrhea, a fever over 102 degrees Fahrenheit (38.9°C), and vomiting—to seek medical attention.
(with agency inputs)