A person who works at Prudential Plaza in the Loop has tested positive for the new coronavirus, prompting at least two companies in the huge office complex to encourage its employees to work from home.

Tenants of the plaza’s two office buildings were notified Tuesday night, hours after the employee was confirmed to have tested positive for COVID-19.

CA Ventures, a real estate investment firm, said Wednesday the coronavirus patient is one of its employees.

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“The employee has not been in the company’s Chicago headquarters since Tuesday, March 3, and has been under quarantine since the diagnosis,” CA Ventures said in a statement.

“Individuals whose work areas are in close proximity to the affected individual have been notified and, although none have presented symptoms, they will remain under self-quarantine for the next 14 days.”

Once it learned of the employee’s diagnosis, CA Ventures said it immediately closed its office and instructed its employees to work remotely.

CA Ventures leases office space at One Prudential Plaza. Sterling Bay, which bought the historic two-tower development in April 2018, told the rest of its tenants Tuesday night that it has begun “aggressively cleaning” all high-touch areas throughout the 2.4 million-square-foot complex.

Sterling Bay also encouraged its tenants “to discuss the logistics of possible work-from-home programs” but advised that both Prudential buildings “will be open for business” Wednesday.

The Chicago Tribune is another tenant. A spokesman for Tribune Publishing said Wednesday it was “encouraging Prudential-based employees to work from home” because of the confirmed case of coronavirus.