Norwegian adventure cruise line Hurtigruten has been hit by COVID-19 cases among crew members after being among the first to bring back cruise itineraries in Europe.

The sad news, which will be a blow to passengers hoping a gradual and monitored return to cruising would prove successful, was announced at the weekend.

Four crew members from the ground-breaking expedition vessel Roald Amundsen were admitted to hospital in Tromsø, Norweay after the ship docked there on Friday, after the vessel had completed a seven-night sailing to Svalbard, in the Arctic.

On Saturday, the line said another 32 crew members had tested positive for the illness.

The ship is in isolation, with the remaining 154 crew being rested.  So far, 122 have returned negative results.

But the concern now is for the passengers. All 178 are now in self isolation after being contacted by the line, and 209 who were aboard a previous sailing have also been told to quarantine.

The Roald Amundsen’s next voyage, due to start at the end of this week, has been cancelled.

It will be a bitter blow to Hurtigruten, renowned for its safety as an exploration company.  It had taken all precautions, including limiting passengers to selected European countries.

There were special cleaning measures, added medical screenings for passengers and crew and below 50% of normal capacity to ensure social distancing.

The line cruising out of Hamburg from Norway in June with the 530-passenger Fridtjof Nansen. The Roald Amundsen and the 335-passenger Spitsbergen were added last month when all seemed well.

“We are now focusing all available efforts in taking care of our guests and colleagues,” a line spokesman said in a statement posted on the line’s website. “We work closely with the Norwegian national and local health authorities for follow-up, information, further testing, and infection tracking.”

The Roald Amundsen currently is scheduled to begin sailings around the British Isles for U.K. residents in early September.

One hundreds Australians were trapped aboard the Roald Amundsen at the height of the pandemic in March after Chile refused to allow the ship to dock.