A Chipotle restaurant just northwest of Boston shut its doors on Tuesday after an employee fell ill with norovirus, the stomach illness that, along with E. coli, has plagued branches of the burrito purveyor across the country in recent months.

Though only one employee has been diagnosed with the virus, three others have reported feeling ill. As of now, no customers are known to have contracted it.

Just last month, Chipotle held a nationwide staff meeting on food safety, following a months-long string of E. coli outbreaks.

The Massachusetts restaurant, located in the town of Billerica, will be inspected by the health department today. It has not announced when it will reopen.