Atlanta (CNN Business) Amazon, Facebook, Google and Microsoft are all encouraging employees in the Seattle area to work from home due to concerns about the novel coronavirus as the outbreak in Washington grows.

Amazon AMZN revealed earlier this week that one of its Seattle-based employees has been diagnosed with the virus. On Wednesday, Facebook said a contractor who works at one of its offices in Seattle had tested positive.

Facebook FB has closed the facility, which the worker last visited on February 21, for the rest of this week.

"We've notified our employees and are following the advice of public health officials to prioritize everyone's health and safety," Facebook said in a statement.

Both tech giants are encouraging employees in the Seattle area to work from home through the end of the month.

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