CHICAGO — One of the top health officials responsible for coordinating the response to the outbreak of the new coronavirus in suburban Cook County was fired without explanation Friday.

Dr. Terry Mason, the chief operating officer of the Cook County Department of Public Health, was terminated after more than a decade working for the county, the Chicago Sun-Times reported. Interim Cook County Department of Public Health CEO Debra Carey released a statement thanking Mason for his service and announcing Doctors Kiran Joshi and Rachel Rubin, senior medical officers, would replace him.

"[Mason] has been a valued member of the executive team and has contributed to our success in recent years," Carey said. Before becoming chief medical officer of Cook County Health in 2009, Mason was the public health commissioner for the city of Chicago and a urologist at Mercy Hospital, according to the Sun-Times. Illinois Coronavirus Update April 4: More than 10,000 Cases: Don't miss updates about precautions in the Chicago area as they are announced. Sign up for Patch news alerts and newsletters.

Carey made the decision to fire Mason, Cook County Board President Toni Preckwinkle told the Chicago Tribune. She declined to comment on why he was terminated because she does not comment on personnel matters, the Tribune reported.