One person died and several others became ill in the US after contracting Escherichia coli bacteria while eating at chain restaurants McDonald’sthe American health authorities announced yesterday Tuesday.

Most of the infected people are in the states of Colorado and Nebraska, but the problem affects a total of ten states in the western US, the Centers for Disease Control and Prevention (CDC), the main US public health agency, said in a press release.

Her stock McDonald’s was down more than 8% in after-hours trading on the New York Stock Exchange.

In total, 49 people were infected by the same strain of E.coli, ten of whom had to be hospitalized.

He died of old age in Colorado.

“All of the people interviewed said they ate at McDonald’s before they got sick, and most of them said they ate a (specific) hamburger” known as a “Quarter Pounder” in the US.

The latter may be withdrawn and “temporarily unavailable” in some states, the CDC added.

The specific ingredient that caused the E. coli infections has not yet been identified, but it may be either the ground beef or the onions. Both of those ingredients were recalled by McDonald’s in the states where contamination was reported to investigate the matter, according to the public service.

The bacterium E.coli generally causes stomach cramps, sudden onset of watery diarrhea, often bloody, vomiting and fever, which is however not very high, symptoms lasting three to four days. Most of those infected recover without treatment, but some may develop complications and even die.

McDonald’s did not immediately respond when AFP sought comment.