More than a dozen people have reported becoming ill after eating at a Chipotle Mexican Grill restaurant in Virginia, which is temporarily closed for cleaning amidst denials from corporate officials and dropping stock prices.

“The reported symptoms are consistent with norovirus. Norovirus does not come from our food supply, and it is safe to eat at Chipotle. We plan to reopen the restaurant today,” said James Marsden, Chipotle’s top food safety official, in a statement released today by the chain’s public relations head Chris Arnold.

Norovirus is often spread via foodborne routes, according to the Centers for Disease Control and Prevention, which reports the highly contagious virus causes symptoms like stomachaches, nausea, diarrhea and vomiting. It’s the most common cause of foodborne illnesses in the United States, with more than 21 million cases annually.

The outbreak was detected by Patrick Quade’s website, which initially received eight reports about a total of 13 people becoming very sick after eating at the Chipotle location on Tripleseven Road in Sterling, VA, on Friday and Saturday, July 14 and 15. After news reports today about the outbreak, additional customers who ate at the implicated restaurant posted information about illnesses on the website.

Virginia state and Loudoun County health officials did not immediately respond to requests for comment on the investigation into the apparent foodborne illness outbreak.

In the official corporate statement from Denver-based Chipotle, the executive director for food safety said the company is “working with health authorities to understand what the cause may be and to resolve the situation as quickly as possible.”

“We take every report of illness seriously. In accordance with our established protocols, our team is working to ensure the safety of our customers and employees, including voluntarily closing the restaurant yesterday to conduct a complete sanitization,” Marsden said, according to Chipotle’s public relations director.

Marsden was hired after the restaurant chain suffered crushing losses following six foodborne illness outbreaks at its restaurants in the last half of 2015. Those outbreaks sickened hundreds across numerous states from coast to coast.

This morning, Chipotle stock had fallen 7.6 percent, according to MarketWatch, which reported it at $362.40 per share.

Chipotle is scheduled to present recent financial data to stockholders on July 25.