An E.coli outbreak linked to a popular McDonald's burger has sickened more people, bringing the total cases to 104 people across 14 states.
A CDC update Wednesday said at least one more case of E.coli has been detected in connection with the sliced onions on the fast food chain's Quarter Pounder.
The new patient has been identified in North Carolina, but no further details were given.
The update also reported that 34 people have been hospitalized, four have developed a life-threatening kidney disorder and one people has died.
Illnesses began on dates ranging from Sept. 12 to Oct. 21 of this year, but there are likely more to come as symptoms E.coli usually take between three to four weeks to appear.
The agency also said the 'true number of sick people in this outbreak is likely much higher than the number reported' because many people recover from E.coli with mild symptoms or without ever receiving treatment.
Last month, investigators at the CDC confirmed the chopped yellow onions, produced by California-based Taylor Farms, in Quarter Pounders were the likely source of the E.coli outbreak.
The onions from the burgers (pictured) have been at the center of an investigation into an E.coli outbreak that has so far hit 49 people, put ten in hospital and left one dead
The burgers were withdrawn from a fifth of McDonald's restaurants , but it has now returned — although in 700 locations it is being served without the onions.
Burger King, Taco Bell, KFC and Pizza Hut have all also stopped using onions as a 'proactive' measure amid the outbreak.
Victims of the outbreak are now suing McDonald's over their illnesses.
Clarissa DeBrock filed suit last month for compensation for lost wages, medical bills and physical and emotional suffering.
She became ill after eating a Quarter Pounder in Nebraska in September.
The burger looked and tasted normal, but five days later she started to suffer from abdominal cramps, diarrheoa and nausea. Her symptoms became so severe that on September 25 she went to the emergency department.
Tests showed she had been infected with E.coli strain O157:H7, the same one connected to the recent outbreak.
In the US, about 265,000 people come down with E.coli every year and more than 100 people die from the disease — according to health officials.
Infections are most commonly caused by eating contaminated food, such as ground beef — where a contaminated part of an animal's intestine has got into the supply — vegetables, which may have been grown using contaminated water, and unpasteurized milk.
Older adults, young children and those with underlying conditions are particularly at risk from the bacteria because they have weakened immune systems.
Patients usually start to suffer symptoms three to four days after being infected, although they can start more than a week later.
These include diarrhea, stomach cramps and nausea, which may clear up within a few days.
If people start to suffer from diarrhea that is persistent, severe or bloody, however, it is recommended that they seek urgent care in hospital.