On Thursday, health officials said that about 400 people have recently reported falling ill after dining at a suburban Kansas City dinner theater, and some of them have even tested positive for norovirus.

In a news release, the Kansas Department of Health and Environment said that the diners who fell sick had consumed food at the New Theatre Restaurant in Overland Park, Kansas since January 15.

Health officials said that laboratory tests have confirmed that four people who got ill had norovirus, which generally leads to stomach pain, vomiting and diarrhea.

On Thursday, New Theatre representatives couldn’t be reached immediately for comment. While speaking to the Kansas City Star newspaper, Rob McGraw, vice president of sales and marketing for the theater, said that three employees and a customer, served by them had tested positive for norovirus however, none of the employees who worked since January 17 had reported feeling sick.

Norovirus has been associated with illnesses suffered recently by dinners at Chipotle Mexican Grill restaurants in California and many other states. Earlier this month, the US Justice Department said that its consumer protection unit has been investigating a norovirus outbreak at a Chipotle restaurant in California.

The Kansas state health department has asked everybody, who had gone to the theater, to fill out a survey as part of its outbreak investigation.

The department mentioned that norovirus spreads from one person to another via contaminated food or water or by coming in contact with a contaminated surface.