Initial testing of people who got sick after eating at a Chipotle restaurant in Boston showed the presence of norovirus, health authorities said Tuesday.
Boston College says 80 of its students, including members of the men's basketball team, got sick. The Boston Public Health Commission reported 65 known cases.
The norovirus causes 20 million cases of gastrointestinal illness in the United States each year, according to the Centers for Disease Control and Prevention.
"We urge residents to take proper precautions to prevent the spread of illness, which include: washing your hands regularly, avoiding close contact or sharing food and drink with others who might be ill, and staying home if you are ill," the Boston commission said in a statement, announcing initial results.
The news comes amid an E. coli outbreak linked to other Chipotle Mexican restaurants that has made people sick in at least nine states since October.
The company had said that it had no evidence to suggest a connection between that outbreak and the Boston incident. It temporary closed its Cleveland Circle location, where the students ate, while health officials investigated.
The CDC said last week that 52 people in nine states -- Illinois, Maryland, Pennsylvania, California, Minnesota, New York, Ohio, Oregon and Washington -- have become ill in the E. coli outbreak.