Six-thousand passengers were being held on a cruise ship off Italy on Thursday while doctors checked on two tourists from Hong Kong who had a fever, the Red Cross said.
The pair becoming ill sparked fears they could have contracted a new virus, Italian media said.
The Red Cross was on hand in case the tourists need to be transferred to the special hospital in Rome - the Lazzaro Spallanzani National Institute for Infectious Diseases.
It comes as China counted 170 deaths from the new virus Thursday and more countries reported infections, including some spread locally, as foreign evacuees from China's worst-hit region returned home to medical observation and even isolation.
The new virus is from the coronavirus family, which includes those that can cause the common cold as well as more serious illnesses such as SARS and MERS.