McDonald’s Corp shares are facing selling pressure Wednesday after an E. coli outbreak was linked to the restaurant chain’s hamburgers.

What Happened: The U.S. Centers for Disease Control announced late Tuesday that 49 cases of E. coli have been detected across 10 states. Cases started popping up last month and have continued into October. At least 10 people have been hospitalized so far and there is one reported death.

“This is a fast-moving outbreak investigation. Most sick people are reporting eating Quarter Pounder hamburgers from McDonald's and investigators are working quickly to confirm which food ingredient is contaminated. McDonald's has pulled ingredients for these burgers, and they won't be available for sale in some states,” the CDC said.

The E. coli O157:H7 strain behind the McDonald’s outbreak reportedly causes serious illness. It’s also the same strain that was responsible for an incident at Jack in the Box in 1993 that killed four people, according to Reuters.

McDonald’s stopped using fresh slivered onions and quarter pound beef patties in several states while the investigation is ongoing. Quarter pound beef patties are only used in quarter pounders and fresh slivered onions are primarily used on quarter pounders.

“Across the McDonald's System, serving customers safely in every single restaurant, each and every day, is our top priority and something we'll never compromise on,” the fast-food chain company said in a statement.

“The initial findings from the investigation indicate that a subset of illnesses may be linked to slivered onions used in the Quarter Pounder and sourced by a single supplier that serves three distribution centers. 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.”

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Analyst Changes: Multiple analysts weighed in on the stock on Wednesday.

Baird analyst David Tarantino downgraded McDonald’s from Outperform to Neutral and lowered the price target from $320 to $290.

Guggenheim analyst Gregory Francfort downgraded McDonald’s from Buy to Neutral and announced a price target of $285.

TD Cowen analyst Andrew Charles reiterated McDonald’s with a Hold and maintained a price target of $300.

Wedbush analyst Nick Setyan reiterated McDonald’s with an Outperform and maintained a price target of $295.

MCD Price Action: McDonald’s shares were down 4.24% at $301.33 at the time of publication, according to Benzinga Pro.