Japan ship
Italian-operated cruise ship the Costa Atlantica is anchored at a port in Nagasaki, southern Japan. Image Credit: AP

Tokyo: At least 34 crew members aboard a cruise ship docked in the Japanese city of Nagasaki have tested positive for coronavirus, local authorities said on Wednesday.

The Costa Atlantica first arrived in Nagasaki in January to undergo repairs, with several hundred crew on board.

Over the weekend, the ship's operator contacted local authorities seeking help to test suspected cases on board.

An initial four tests carried out on the ship revealed a first infection on Monday, with additional testing among 57 crew finding a total of 34 cases by Wednesday.

"Many infections have been confirmed on the ship," Nagasaki governor Hodo Nakamura told reporters on Wednesday.

"We hope that they will be able to go home in full health as soon as possible. We are asking the national government for help."

Nakamura said those infected and other crew members remain on the ship, adding that the ship's operator has told local officials that crew members are self-isolating.

Japanese officials have not yet been on board, with testing carried out by medical personnel among the ship's crew using kits supplied by local medical facilities.

Japanese officials said they needed more time to draw up a detailed plan and gather enough trained personnel and more equipment before boarding the ship.

Nagasaki officials said no one on board the ship was believed to be in serious condition so far.

Day trippers

The exact number of people on the ship was not immediately clear, though initial reports said 623 crew of various nationalities had been on board.

Some are believed to have moved around inside Nagasaki city in recent weeks.

Further testing among other crew members was expected to be carried out.

"We have not yet decided exactly how many and how we will administer PCR tests (to detect the infections)," said Katsumi Nakata, chief of the regional government's health and welfare department.

"We have to be careful and do it gradually. We have to be fully protected (to take samples from crew members) when we have so many people," he added.

The prospect of a cluster of infections on the ship comes months after Japan dealt with a massive outbreak aboard the Diamond Princess, a cruise ship that docked in the city of Yokohama after a former passenger tested positive for the virus.

Japanese officials opted to carry out a much-criticised onboard quarantine that they argued would limit infections, but more than 700 people ultimately contracted the virus and 13 people died.

Overall, Japan has seen a relatively small outbreak compared to parts of Europe or the United States, with around 11,500 infections and 277 deaths recorded so far.

But a recent jump in infections has caused concern, put pressure on local healthcare facilities and prompted the government to declare a month-long state of emergency that will run until May 6.