NAGASAKI--Seven days before Japan quarantined a cruise ship near Tokyo early this year, in what became one of the first coronavirus hot spots outside China, another cruise ship docked in southern Japan.

For the next five weeks, as the virus took hold in Japan and the Diamond Princess in Yokohama port grabbed global attention, the Japanese authorities issued no warnings to the Costa Atlantica 1,200 kilometers to the southwest.

Passengers from the Yokohama ship were dying while people from the other vessel freely got on and off, dining and shopping in Nagasaki, and dozens of new crew members were flown in to replace those whose work contracts were expiring.

The Costa Atlantica now hosts one of Japan’s biggest clusters of the coronavirus, which infected one-fourth of the more than 600 people then on board. Public-health experts say a lack of additional measures on cruise ships after the Diamond Princess outbreak, toothless coronavirus legislation and a nationwide paucity of virus testing combined to allow the outbreak on the Costa Atlantica to blossom. This was compounded by local and national authorities’ decision to corral infected and uninfected people on the Costa Atlantica, making it harder to stem the on-board infection.

“It seems that a situation similar to the Diamond Princess is being created,” said Amesh Adalja, an infectious-disease specialist at the Johns Hopkins Center for Health Security. “In an effort to keep cases from disembarking, more cases will occur among the (people on board), some of which could be severe and preventable.”

The law authorizing Prime Minister Shinzo Abe’s national state of emergency and restrictions on movement by various regional governors carries few legal penalties, part of Japan’s postwar aversion to curbs on personal liberties. It relies instead on social pressure and respect for authority.

The lack of widespread testing or infection-tracing apps in Japan complicates the response in Nagasaki. Health officials say they are struggling to trace infection routes and do not know how the virus spread to the ship.

Abe’s government defends its cautious testing policies, saying it wants to avoid swamping hospitals with people who have only light cases. And while the virus has spread steadily, infections did not spike in Japan, as in some countries, and new cases have slowed since mid-April. Japan had confirmed about 15,000 coronavirus infections as of Tuesday, and 543 people are known to have died from COVID-19.

The Diamond Princess, which had more than 3,700 people on board, initially kept them all on the ship, contributing to the spread of infections to more than 700 and the deaths of 14.

The 86,000-ton Italian-flagged Costa Atlantica carried no passengers when it docked for maintenance in Nagasaki. Of the initial 623 crew on the ship, 149 tested positive and five of those have been hospitalized.

That makes it one of Japan’s biggest clusters, according to Reuters calculations based on Oxford University data.

The Costa Atlantica and the Diamond Princess are both ultimately operated by Florida-based Carnival Corp.

“Sick crew members should be fully treated at local hospitals, but healthy crew should be returned to their home countries as soon as possible,” said Takanori Hamasaki, head of a local residents’ association. “I think those who tested negative can turn positive while they are staying on the ship,” Hamasaki told Reuters in late April. “Honestly, their cabins on the ship are small--no one can stay healthy in that situation.”

About two weeks after the first case was detected, operator Costa Cruises S.p.A. began flying healthy crew members home. By Tuesday, 181 mostly Indonesians and Filipinos crew had been repatriated, the local government said. There has been no decision whether to repatriate people who test positive, said Katsumi Nakata, a senior official with Nagasaki Prefecture.

Costa Cruises said in a statement, “The health and safety of our people, along with compliance and environmental protection, is always our utmost priority.”

The Mitsubishi Heavy Industries Ltd. unit that operates the Koyagi shipyard where the Costa Atlantica is docked apologized to local residents late last month for “causing concern” and “misunderstanding” over the outbreak and said it would “fully cooperate” with the authorities. Kunio Shiiba, a senior executive at Mitsubishi Heavy, bowing deeply at a news conference, also apologized for insufficient explanation about the crew members’ movement.

Costa Cruises manages health checks of the crew and their movement on and off the ship, while Mitsubishi controls the shipyard entrance and checks the temperature of those coming in, Shiiba said. Hamasaki of the residents’ association said that while Mitsubishi apologized to them and explained the steps it had taken, the company offered no specific steps to avoid further infection.

“What we can do is wash our hands and wear masks,” he said. “This is going to be a long battle. If it drags on, it will be a problem for all of Japan, not just in Nagasaki.”

DEATH IN YOKOHAMA, RAMEN IN NAGASAKI

The Costa Atlantica, diverted from virus-ravaged China, docked in Nagasaki on Jan. 29, five days before the Diamond Princess moored in Yokohama, where infection spread rapidly and the ship was locked down. On March 6, a month before Abe declared the state of emergency, the Nagasaki government asked people to stay home, but local businesses remained open, attracting customers like Sara Zhou, a Costa Atlantica guest-services employee who sampled tomato ramen and Starbucks coffee in downtown Nagasaki.

“Delicious Japanese noodle, that for sure u will finish the last drop of tomato soup. U will love it go and try it,” Zhou wrote on Facebook, the day the seventh person from the Diamond Princess died. She did not respond to Reuters requests for comment.

Eight days later, after the first coronavirus case was reported in Nagasaki, Mitsubishi and the Costa Atlantica operator asked the crew to stay on board.

That request also went unheeded. More than 30 people left and boarded the vessel from April 1 to 20, when the ship’s first case was detected and the movement stopped, said local government official Futoshi Iwasaki.

A health ministry official handling the Costa Atlantica told Reuters the ministry “wasn’t in a position to give orders and we don’t have the power to enforce them.”

Now in their cabins, the crew while away the time chatting with each other from their balconies and hand-washing their laundry.

Healthy workers spray disinfectant around the ship. Pictures shared with Reuters show one wearing a helmet, goggles and mask with a plastic bag over his torso as he distributes meals to colleagues.

“People are thanking me for working as a frontliner. And I am happy to hand over sugar and salt they need,” the Filipino crew member told Reuters on condition of anonymity. “It is my best nightmare.”