CHICAGO (CBS) — A Cook County correctional officer has tested positive for COVID-19, the Cook County Sheriff’s office announced Sunday.

The officer, who had recently worked in the residential treatment unit at Cermak Hospital attached to the Cook County Jail, was in isolation at home Sunday.

The Sheriff’s office used video to determine who might have come into close contact with the officer. After consulting with the Chicago Department of Public Health, a small number of staffers were asked to stay home – even though they were not symptomatic.

Out of an abundance of caution, they will self-quarantine for 14 days.

The areas where the officer worked were thoroughly cleaned and disinfected, the Sheriff’s office said.

To reduce chances of exposure and infection, the Sheriff’s office is regularly updating communications with the staff for best practice in fighting the coronavirus.

Earlier this month, Sheriff Tom Dart began a number of measures at the Cook County Jail to prevent the spread of the virus – including halting detainee social visits, creating new housing tiers for inmates where they are observed for symptoms, and consulting with environmental health expert and former Department of Justice monitor Harry Grenawitzke.

COVID-19 has already made its way into correctional facilities around the country, including Georgia, Michigan, New Jersey, and New York.

The Sheriff’s office said it is prepared to respond if any detainees or additional staff contract COVID-19.

Meanwhile in a court hearing on Monday morning, the Cook County Public Defender will be making an emergency petition for the release of certain jail detainees in the wake of COVID-19.