A third person in Illinois has presumed to have tested positive for COVID-19, better known as coronavirus, the Chicago Tribune and NBC Chicago report.

The "presumptive positive" test was reported by the Northwest Community Hospital in Arlington Heights, a suburb of Chicago. The CDC has not yet confirmed the diagnosis.

In a statement to the Chicago Tribune, the hospital said that it had opened an exposure investigation and "is closely following recommended guidelines."

NBC Chicago reports that a school district in Arlington Heights said in a letter Sunday night that two staff members and their children had been exposed to the patient. None of those exposed to the patient have experienced any symptoms of COVID-19, and all are currently self-quarantined at home while they monitor for symptoms.

In January, two Chicago residents were diagnosed with COVID-19. The patients, a couple, had just returned from a trip to Wuhan, China — the center of the virus outbreak. Both patients made a full recovery.