map_seattle_maineLate Monday, Chipotle closed a restaurant in Boston after Boston College said 30 of its students complained of gastrointestinal symptoms after eating at the chain. The school said it was working with health authorities to investigate the cause.

This morning Chipotle says it believes Norovirus is to blame for sickening Boston College students who ate at its restaurant. The company says it thinks the illnesses are an isolated incident unrelated to an outbreak of E. coli cases tied to its restaurants.

Almost 200 guests who attended a catered event in downtown Seattle last week reported feeling ill with norovirus afterward. Two people were hospitalized. As the Seattle Times noted:

The Russell building is home to a number of high-profile residents, including Zillow and notable food-safety law firm Marler Clark. The building remained open, but underwent a top-to-bottom cleaning over the weekend to eradicate the germ. No one is sick in his office, Marler said. According to a report from the Seattle Times, a catered event held at the Russell Investments Center was ground zero for the infection.

Norovirus causes nausea, vomiting and diarrhea, which can lead to serious dehydration.