The DuPage County Health Department said it's looking into any reports of exposure, with help from the Illinois Department of Public Health, the Centers for Disease Control and Prevention and local health care providers.
So far, no one else appears to have come down with the virus. Five confirmed cases have been identified nationwide. The CDC said in a Wednesday afternoon updated that 165 people are under investigation across the country, 68 have tested negative, and only five have tested positive.
So far, it is not spreading through any community but health officials are prepared for that to change.
"This is a new and rapidly changing situation," said Karen Ayala of the DuPage County Health Department. "We expect there may be more cases and more individuals to follow up with in the coming weeks."
All five of the confirmed cases involve individuals who visited the Chinese city of Wuhan, where this strain of the coronavirus appears to have originated.
Health officials with DuPage County said people who may have been exposed to the Chicago woman diagnosed with the virus have not shown any symptoms so far. Their main message to the public is not to panic.
DuPage County health officials said the general population is at low risk of contracting coronavirus, and people can take simple preventative measures as they would with any other upper respiratory infections, including covering your mouth and nose when you sneeze and cough and washing your hands regularly.
"The same steps that will keep you safe and healthy from the flu will keep you safe and reduce your risk of contracting the novel virus even further," Ayala said.
Local health officials are far more concerned about the flu than coronavirus; already six people in DuPage County have died from flu, and another 32 people have been hospitalized. Officials stressed it is not too late to get a flu shot.
Wednesday a plane carrying 195 Americans traveling from the virus hot zone in China returned to the U.S.
"In Anchorage I asked the first U.S. Customs guy I saw, 'Where's the nearest U.S. soil I can kiss?'" said passenger Patrick Stockstill.
Crews met the passengers wearing protective white suits, and some of the passengers wore face masks. Officials said all were tested for the virus twice in China, twice in Alaska where the plane refueled, and again when they landed at March Air Force Base in Southern California.
"We're here to ensure their safety, and also those on base, those in this community, and elsewhere in America," said Dr. Charles Braden, CDC.
All of the passengers also agreed to a voluntary three-day quarantine on the base. If they don't show any symptoms during that time, they will be allowed to go home where they will be monitored for two weeks.
In the meantime, there are still some 800 Americans believed to still be trapped in Wuhan who just want to come home.
"You're scared. We understand that there's a lot about this virus that we don't know, but something that we also have to keep in mind is these folks need to come home," said Dr. Cameron Kaiser, Riverside County Public Health Officer.
On Wednesday, U.S. and British airlines halted flights to China in efforts to contain the virus.
American Airlines suspended Los Angeles flights to and from Shanghai and Beijing, while British Airways halted all flights to China. The carriers joined several Asian airlines that are either suspending or cutting back service to China as fear about the virus spreads.
Tuesday Porter County health officials reported a possible case of coronavirus in northwest Indiana.
County health officials said they identified an "individual traveling through Porter County" as potentially infected. A final diagnosis has not been reached, and health officials are waiting on results from laboratory tests by the Centers for Disease Control and Prevention.
The patient has been placed in isolation out of an abundance of caution, health officials said. That person is currently under active medical supervision.
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There have been more than 130 deaths from coronavirus and roughly 6,000 infections reported in China, according to Chinese health officials. More than 50 cases have been reported outside China.
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Scientists say there are still many critical questions to be answered about the new virus, including just how transmissible and severe it is.
Dr. Michael Ryan, the World Health Organization's emergencies chief, said many of those affected experience only a mild illness and estimated that the death rate is at about 2%. The death rate for SARS, a related virus, was about 10%.
Ryan said few instances of the new virus spreading between people in countries beyond China, including Germany, are of great concern.
The new virus causes cold- and flu-like symptoms, including cough and fever, and in more severe cases, shortness of breath and pneumonia.
The Associated Press contributed to this report.