Facebook Inc. said an employee in Seattle has been diagnosed with coronavirus, the first known infection within the company as the virus continues to spread in the region.

The employee, a contractor, was last in Facebook’s Stadium East office in Seattle on Feb. 21. The company alerted employees tonight and said the Seattle office will be closed to all employees until March 9. Employees in Seattle are also being encouraged to work from home until the end of the month.

“A contractor based in our Stadium East office has been diagnosed with the COVID-19,” a company spokesperson said in a statement. “We’ve notified our employees and are following the advice of public health officials to prioritize everyone’s health and safety.”