Norovirus confirmed in Boston students who ate at Chipotle

A sign is seen at a Chipotle Mexican Grill restaurant in San Francisco, California July 21, 2015. REUTERS/Robert Galbraith (Copyright Reuters 2015)

A number of Boston College students sickened after eating at a Chipotle Mexican Grill were affected by norovirus, the Massachusetts Department of Health said, confirming that the source of the outbreak was different from the one causing a spate of illnesses in several states.

Chipotle has been under scrutiny since November, when it was first linked to an E. coli outbreak that has sickened 52 people in nine states.

The burrito chain said on Monday it had temporarily closed the restaurant in Boston's Cleveland Circle where the students had eaten.

Shares of the burrito chain were up 1.2 percent at $549.01 in afternoon trading.

"Since late Sunday evening, more than 120 Boston College students have reported to Boston College Health Services with symptoms consistent with the norovirus," Boston College spokesman Jack Dunn said.

The students have also been tested for E. coli, but results are awaited, he said.

Norovirus is a highly contagious virus that is spread by contaminated food, improper hygiene, and contact with contaminated surfaces.

The virus can cause nausea, vomiting and diarrhea and incubation can occur between two and eight days.

The E. coli outbreak last month was the company's third food safety incident since August. It has raised concerns about potential reputational damage to the fast-growing brand that has won a loyal following for its food made with fresh produce, meats raised without antibiotics and ingredients that are free of genetically modified organisms, or GMOs.

In August, norovirus was blamed for sickening nearly 100 people at a Chipotle restaurant in Simi Valley, California.