Health officials believe a Chicago man who was diagnosed with coronavirus is the first community-transmitted case of the virus in the city.

The resident, a man in his 60s, is currently hospitalized and is in serious condition, according to health officials.

Officials say that the man has not traveled to any countries impacted by coronavirus, and that he has no connection to any other existing cases.

"The investigation is still ongoing, but based on what we know so far, this case has not been linked to any travel or to any COVID-19 case," Dr. Allison Arwady, Director of the Chicago Department of Public Health, said.

The man's case is the seventh diagnosed case of coronavirus in the state of Illinois. The first two individuals diagnosed with the disease have fully recovered, while the third, fourth and fifth individuals diagnosed are still recuperating at home.

A sixth individual, a teacher's aide at Vaughn Occupational High School on Chicago's North Side, remains hospitalized and is in good condition.

Chicago Public Schools extended the closure of Vaughn Occupational High School after learning new information about a teacher's aide who was diagnosed with the coronavirus. NBC 5's Chris Hush reports.

Officials also provided an update on the teacher's aide, saying that she is in good condition and recovering after her diagnosis.

Health officials have begun testing any individuals with symptoms consistent with coronavirus, but have not had any positive tests. School buses used by the school, and the school itself, are being thoroughly cleaned while students and faculty are under at-home quarantine.

Dr. Arwady says that it is likely health officials will have made contact with all members of the staff and faculty, as well as parents of students, by the end of the day Sunday to determine whether they are experiencing symptoms.

Individuals who were in close contact with the teacher’s aide at the school have been asked to self-quarantine until March 18, but Arwady said that it is not necessary to cancel large-scale public events at this time.

"There is not a recommendation to cancel mass events at this time," she said. "However, business and community organizations are encouraged to review their existing emergency plans."

Arwady said that the number of cases in the state is expected to rise as more surveillance programs are put into place, and also warned that with the seventh case being considered a "community-transmitted" case, officials are also expecting that those numbers will rise as well.

"The potential for more community transmission is absolutely there," she said.

Officials are continuing to remind residents that the best way to avoid becoming ill with coronavirus is to wash hands often, to cover one's face while coughing, and staying home if they feel sick.

Hand sanitizer is flying off shelves because of concerns over the coronavirus, but if you can’t find the substance at your local store, you can still make your own to help keep your hands clean until you can find it again. NBC 5's Charlie Wojciechowski explains how.

People who are older or have underlying health conditions should consider avoiding travel and large gatherings, according to health officials.

In the fifth case, a Vanderbilt University student was diagnosed with the virus after returning from a study abroad program in Italy. The student was recently released from a local hospital.

The other four individuals in Illinois who had tested positive for the virus have been released from area hospitals.