(Updated at 9:25 p.m.) Two cases of coronavirus — one confirmed and one presumptive — have been identified at the Reston-based headquarters of the U.S. Geological Survey (12201 Sunrise Valley Drive), according to an email reviewed by Reston Now.

An employee, who works on the fifth floor of the main building, is currently in isolation, pending the confirmation of test results, according to a USGS spokesperson.

Test results confirmed another individual, who visited the building on Thursday, March 12, tested positive for the virus. USGS found out about the two cases yesterday (Tuesday).

The case was linked to the John Wesley Powell Federal Building, the main building at the national center. The Reston campus, which sprawls over 105 acres, remains open. Officials are encouraging employees to consult with their health care provider and notify their supervisor if they believe they may have been exposed, the email states.