PHILADELPHIA (CBS) — While two potential cases of coronavirus have been eliminated in Philadelphia and New Jersey, a new suspected case is being investigated by the Philadelphia Health Department. Screenings for the virus at U.S. airports have been expanded and now include Philadelphia International Airport.

The airport is now checking passengers from certain flights for coronavirus.

The expanded airport checks come as cases have surged in China, where there are now 4,500 patients and 100 deaths.

In Philadelphia, we have no additional information on the newly identified possible case here, but lab tests have come back negative for one that was pending.

William Penn Charter School in East Falls says the Chinese exchange student who had suspicious symptoms does not have coronavirus.

In China where the virus started, authorities in full protective gear are checking temperatures and sending those with fevers immediately to the hospital.

In Bangkok, Thai Airways is disinfecting planes in hopes to contain the spread of the respiratory virus.

United States health officials are warning against any non-essential travel to China and have increased the number of screening sites from five U.S. airports to 20, including Philadelphia International Airport.

“Our regular activities at quarantine stations focus on identifying ill patients and that’s what we’re going to be doing here — identifying ill travelers returning from China so we can make sure they’re appropriately treated, don’t pass this illness to others,” Nancy Messonnier, from the National Center for Immunization and Respiratory Disease, said.

There is no indication coronavirus is being spread inside the United States. All identified patients so far have traveled to China.

“Americans should know this is a potentially very serious public health threat but at this point, Americans should not worry for their own safety,” said Health and Human Services Secretary Alex Azar.

For the United States nationals stuck in Wuhan, which remains locked down, the State Department has chartered a flight to evacuate about 230 diplomats and U.S. citizens, especially those at greatest risk.

Wisconsin father Sam Roth hopes his wife and two small children get on board.

“We have a 10-month-old and a 5-year-old. They are susceptible. They should be prioritized,” he said.

Newark, Boston and Washington, D.C. are also additional airports included in the screenings.

The number of confirmed cases in the United States is still at five. The New Jersey Health Department has set up a special hotline to answer questions about coronavirus.

New Jersey’s hotline can be reached at 1-800-222-1222.

Stephanie Stahl