Boston College said all students who reported symptoms have been tested for both E. Coli and norovirus, and that results will not be available for at least two days.
According to a report from the Boston Inspectional Services department dated Monday, an employee at the Chipotle restaurant in Boston was sick while working a shift Thursday.
William Christopher, commissioner of the department, said at a briefing Tuesday that it was not immediately known if the restaurant's management was aware of the employee's symptoms. The restaurant's permit to operate has been suspended by the city and a disinfection process has begun, Christopher said.
Scott Zoback, a spokesman for the Massachusetts Department of Public Health, said the agency had no update on the cause of the illnesses at Boston College. He said test results from specimens sent to labs were expected back later Tuesday or Wednesday.
People can get norovirus from an infected person, contaminated food or water, or by touching contaminated surfaces, according to the Centers for Disease Control and Prevention. The virus is very contagious and can spread quickly in places such as daycare centers and cruise ships, the agency says. Each year, it causes 19 to 21 million illnesses.
The Centers for Disease Control and Prevention said late last week the outbreak of E. coli tied to Chipotle has sickened 52 people in nine states so far. The first cases were reported at the end of October in Oregon and Washington, and the most recent illness began on Nov. 13.
Chipotle executives noted the exposure period for the E. coli cases appears to be over. The company has said it is tightening its food safety standards.
Chipotle Mexican Grill, based in Denver, has more than 1,900 locations, primarily in the U.S. It has already warned that sales are expected to fall as much as 11 percent at established locations for the fourth quarter as a result of bad publicity from the E. coli cases.
That would mark the first time the sales figure has declined since Chipotle went public in 2006.
In its annual report, Chipotle notes that it may be at a higher risk for outbreaks of food-borne illnesses because of its use of "fresh produce and meats rather than frozen, and our reliance on employees cooking with traditional methods rather than automation."
Chipotle shares fell $11.65, or 2.1 percent, to $540.10 in midday trading Tuesday.
The Associated Press