MADISON - The state agency that oversees retirement funds shut its office to visitors Thursday after officials learned one worker was exposed to someone with coronavirus.

Officials with the State of Wisconsin Investment Board learned late Wednesday that an employee had been exposed to someone who has tested positive for coronavirus on the East Coast, according to Vicki Hearing, a spokeswoman for the agency.

The agency's office in downtown Madison will be closed to the public on Thursday and Friday. Officials will determine over the weekend whether to reopen it to the public on Monday, Hearing said.

The agency's 200 or so employees have been encouraged to work from home. Few were in the office Thursday, Hearing said.

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The employee in question has self-quarantined and is following the advice of a doctor and guidelines set by the federal Centers for Disease Control and Prevention, according to Hearing.

Even before learning the employee had been exposed to someone with the virus, the agency had been disinfecting its office daily, Hearing said.

The investment board manages more than $100 billion for the state, including for the retirement system for public workers around Wisconsin.

The Wisconsin State Journal first reported on the agency closing its office.

Contact Patrick Marley at patrick.marley@jrn.com. Follow him on Twitter at @patrickdmarley.