Six students at the University of Wisconsin-Platteville, who were all recently in Wuhan, China, epicenter for the new coronavirus, are being monitored by the U.S. Centers for Disease Control and Prevention — though none has shown signs of the respiratory disease.

The news comes as a second case was diagnosed in the United States. A Chicago woman in her 60s who had been caring for her father in China earlier this month remained hospitalized Friday with the disease. Earlier this week, a Washington state man became the first U.S. case identified. The disease has sickened at least 800 people and killed at least 26 worldwide.

The Platteville students, who include two residents of Wuhan, arrived on campus Tuesday, according to a university spokesman. The Wuhan residents were screened for coronavirus when they arrived at Chicago's O'Hare International Airport.

All six students are living together in a residence hall on campus and are taking their temperatures on a regular basis — essentially monitoring themselves. Symptoms of the new virus include fever, cough and shortness of breath.

The students are not under quarantine or isolation, said Paul Erickson, the campus' director of communications. He said all six are exchange students from outside the country. He did not know where the four students who were not Wuhan residents came from.

Erickson said UW-Platteville authorities have been in touch with the CDC and the Grant County Health Department and are following national and international health guidelines concerning the illness.

On Thursday, the Wisconsin Department of Health Services held a webinar to provide background on the virus and guidance to local and tribal health officials across the state.

The webinar included instructions on how to handle people who have traveled in the affected area of China but are not showing symptoms, but also specific instructions for isolation of patients who do show symptoms.

Mary Beth Graham, medical director of infection prevention and control for Froedtert Hospital and the Medical College of Wisconsin, said much remains unknown about the coronavirus, and, as a result, guidance may change from one week to the next.

"I'm more concerned about influenza than I am about coronavirus at this point," Graham stressed, explaining that Wisconsin's flu vaccination rate is around 38%, far below the CDC goal of 70%. In a typical flu season, fewer than one-tenth of a percent of infected patients die from the disease.

Graham said that what is unusual about patients with the new coronavirus is that they are developing pneumonia and have difficulty breathing. She said respiratory secretions would be used to test possible cases.

Milwaukee's Health Department declined to comment on specific preparations being made for coronavirus, deferring questions to the state.

However, Paul Biedrzycki, former director of disease control and environmental health for the city, said local officials should be sending out alerts to hospitals and acute care facilities so that staff will be on the lookout for cases of respiratory illness involving recent visitors to Wuhan or other affected areas.

Biedrzycki, who retired from the city Health Department in 2017, said officials should also be making sure the public receives clear messages about the level of urgency involving the virus and precautions they can take to prevent infection.

He cautioned that other coronaviruses that started in animals and spread to people, such as Severe Acute Respiratory Syndrome (SARS), surfaced far from the U.S. and "came to our shores much more rapidly than we expected."

Coronaviruses are a large family of viruses; four main ones circulate commonly through the U.S., causing cold symptoms in the nose and throat.

There are also coronaviruses that are found mainly in animals, including camels, cats and bats.

Although rare, some coronaviruses found mainly in animals cross the species barrier and infect humans.

Health investigators believe the current outbreak began at a large seafood and animal market in Wuhan, suggesting that the illness passed from animals to humans at first.

However, health authorities have now identified patients with the disease who had no contact with the Wuhan market, a sign that the disease may also be spreading from person to person.

Graham, at Froedtert and the Medical College, stressed that important questions remain unanswered about the new coronavirus. Investigators still don't know what animal was the primary reservoir for the virus. The reservoir can harbor a virus without injury to itself.

Also unanswered is the question of what standard treatment to provide patients who become infected with the new coronavirus.

Graham and others said right now the best things people can do to protect themselves from the virus are to wash their hands frequently and avoid people who are coughing and showing symptoms of illness.