One American has died and dozens more are sick amid an outbreak of E Coli linked to McDonald's.
The Centers for Disease Control and Prevention, CDC, said on Tuesday that 49 people in 10 states have been taken ill from the same strain of the deadly bacteria that kills up to one in five sufferers.
Ten of the patients have been hospitalised, including a child who sufferered life-threatening kidney damage from the infection. The fatality was an elderly man in Colorado.
All affected patients had eaten at McDonald's before getting sick, and most of them specifically mentioned ordering the chain's popular Quarter Pounder burger.
Investigators believe the affected ingredient is either slivered onions or the beef patty. McDonald’s has removed both items from stores affected states while the investigation continues.
The chain said its Quarter Pounders - bought by 110,000 Americans in the US every day - may be temporarily unavailable in some states.
Quarter Pounder beef patties are only used on the chain's Quarter Pounder, while the onions 'are primarily used on Quarter Pounder hamburgers and not other menu items,' the CDC said.
No additional details have been released about the Colorado man.
The hospitalized child is suffering from hemolytic uremic syndrome (HUS), a complication of E Coli that can occur when small blood vessels become damaged and inflamed.
This damage can cause clots to form in the vessels all through the body. The clots can damage the kidneys and other organs. HUS can lead to kidney failure, which can be life-threatening.
The first reported illness happened on September 29, with the last reported illness on October 11, according to the CDC.
The agency said it usually takes three to four weeks to determine if a sick person is part of an outbreak.
The CDC reported that most people were in Colorado (27) or Nebraska (9).
Additionally, people in Utah, Wyoming, Kansas, Missouri, Iowa, Wisconsin, Montana and Oregon have all reported cases, though it's unclear how many were in each of those states.
McDonald's North America Chief Supply Chain Officer Cesar Piña said initial findings from the CDC investigation indicate the outbreak may be linked to onions sourced by a single supplier that serves three distribution centers.
He said: 'As a result, and in line with our safety protocols, all local restaurants have been instructed to remove this product from their supply and we have paused the distribution of all slivered onions in the impacted area.'
He added that McDonald's was temporarily removing the Quarter Pounder from restaurants in the impacted areas, including Colorado, Kansas, Utah and Wyoming, as well as portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico, and Oklahoma.
He added': 'We take food safety extremely seriously and it’s the right thing to do. Impacted restaurants are receiving a stock recovery notice today and should reach out to their field supply chain manager or distribution center with any questions.'
He assured buyers all other menu items were unaffected and available.
E. coli are bacteria typically found in the intestines of animals such as cattle, goats, sheep, and deer.
While most are harmless, some can cause a host of gastrointestinal symptoms, including stomach cramps, bloody diarrhea, and vomiting.
The bacteria can be found in food and water contaminated by feces from infected animals.
E coli infection sickens about 95,000 Americans per year and kills around 17 to 20 per cent.
Young children and elderly adults are at the greatest risk of dying from E coli due to having naturally weakened immune systems.
Symptoms include diarrhea, a fever above 102 F, vomiting, and signs of dehydration like not peeing or dry mouth, the CDC said.
The patients in the current outbreak were infected with strain O157:H7, the most common strain in humans that has been shown to cause severe intestinal infections.
The CDC said that anyone who has severe E coli symptoms after eating a Quarter Pounder at McDonald's should seek medical help and tell the provider what they ate.
HUS, which caused the child to be hospitalised, affects about 200 to 300 Americans per year and kills less than one in 20 of those.
Symptoms include bloody diarrhea, stomach cramps, fever, and vomiting. Symptoms usually start three to four days after swallowing the bacteria, and most people recover without treatment after five to seven days.
