The quarantine started Monday, when results came back positive for a guest who had gone ashore in Hong Kong on Jan. 25 and visited a local hospital, The Associated Press reported.
Now, all those aboard the Diamond Princess – which is carrying at least 3,000 guests – are receiving medical checks from quarantine officials and medical staff.
The Diamond Princess is docked off Yokohama Port, near Tokyo. As of Tuesday morning, the ship was quarantined and cruise officials were working with Japanese health authorities to investigate the matter, USA Today reported.
"While on the ship he did not visit the ship’s medical center to report any symptoms or illness," a statement obtained by USA Today reads. "The hospital reports that he is in stable condition and the family members traveling with him remain symptom-free."
The Diamond Princess cruise departed Yokohama on Jan. 20 and was scheduled to return on Tuesday after making port calls in Vietnam, Taiwan and Okinawa.
The passenger, who is from Hong Kong, has claimed that he remained unaware of his coronavirus diagnosis until six days after he disembarked in Hong Kong. The man has alleged that health authorities in Hong Kong initially failed to identify the virus through a thermal screening, The Associated Press reports.
“I wish we were informed as soon as they found out, then I could have worn a mask or washed hands more carefully," the passenger said. “I was in Hong Kong nine days ago and it seems to be too late now.”
Though a spokesperson for Princess Cruises was not immediately available to offer further comment, the cruise company has shared the following health advisory regarding the ongoing outbreak to their website:
"Although the risk to our guests and crew is low, we are closely monitoring the evolving situation with respect to Coronavirus originating in mainland China. Our medical experts are coordinating closely with the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) to implement enhanced screening, prevention and control measures for our ships globally," Princess Cruises said in a Jan. 31 update.
As a precaution, booked guests who have traveled through or from mainland China since last Friday will not be allowed to sail. The measure does not apply to Hong Kong, Macau and Taiwan. Beyond pre-boarding medical evaluations for those who appear symptomatic and medical screenings for guests who visit onboard medical centers with respiratory illness symptoms, crew members from mainland China are delayed from embarking on any Princess Cruises ship until further notice.
As of Tuesday morning, 20,438 people were reportedly infected with the coronavirus, while the death toll has risen to 425. There were also 11 confirmed cases in the U.S.
Meanwhile, the ongoing outbreak continues to impact travel around the world.
Last week, 6,651 people were held on Costa Cruises’ Costa Smeralda ship in an Italian port after a passenger from Macau, China, came down with flu-like symptoms that officials feared indicated coronavirus. Passengers and crew were allowed to disembark after the sick passenger tested negative for the virus.
On Feb. 1, AIDA Cruises ship AIDAperla was turned away by authorities in the Caribbean island of St. Lucia “due to some guests with upper respiratory tract infections on board,” a spokesperson for the cruise company said.
The Centers for Disease Control and Prevention (CDC) has advised people to avoid all nonessential travel to China. The U.S. State Department raised its China travel advisory to "Level 4: Do Not Travel."
Fox News’ David Aaro and Alexandra Deabler contributed to this report.