A Chicago man in his 60s is the seventh confirmed coronavirus patient in Illinois, public health officials announced Sunday.

Chicago Department of Public Health Commissioner Dr. Allison Arwady said the man is hospitalized in serious condition, but his illness currently has not been linked to travel or any other coronavirus, also known as COVID-19, case.

"I'd also like to reassure people that though this may be the first case of community transmission in Chicago, it does not mean that widespread transmission of COVID-19 is occurring here," Arwady said. "It does mean that the surveillance system we've been working to set up to detect any potential community spread is working."

Because of the growing thread of community transmission in parts of the U.S. and a growing number of countries, Chicago has been preparing for person-to-person spread of the virus for weeks, Arwady said.

As surveillance efforts are enhanced and testing increases as a result, Arwady said additional COVID-19 cases are expected.

"So we'll be working hard today to learn more about this patient's history, but in the meantime, we're taking the possibility of potential community transmission very seriously."

At this time, there is no recommendation in Chicago to cancel any mass gatherings or public events, but businesses and organizations are strongly encouraged to review emergency operations plans and consider strategies for social distancing. People who are older, or with underlying health concerns should avoid travel and large gatherings, Arwady said.

Arwady also provided an update on the sixth confirmed case of COVID-19, which was contracted by a woman in her 50s who is a teaching assistant at Chicago's Vaughn Occupation High School. Arwady said she is in good condition.

Chicago Public Schools has begun a thorough cleaning of Vaughn and has taken buses out of service for cleaning. High traffic areas in all schools will receive extra cleaning and all schools will receive additional cleaning wipes and hand sanitizer starting Monday.

Arwady said the main concern for community transmission is close contact with a patient because the primary way the virus is transmitted is through respiratory droplets when someone coughs or sneezes.

Illinois Department of Public Health Director Ngozi Ezike recommends washing hands for the recommended 20 seconds, covering coughs and sneezes, and staying home when sick.

"These are the measures that seem mundane, but really will help us get a handle on the illness and the spread of germs in our community," Ezike said.

For information on coronavirus threats in Illinois, visit chicago.gov/coronavirus.