A Norwegian cruise ship suffered a coronavirus outbreak just over a month after it set sail for the first time since the pandemic swept the world. Passengers had already disembarked Hurtigruten’s MS Roald Amundsen by the time its owners discovered that 33 crew members had tested positive as it sat docked in Tromsø, Norway on Friday. The ship took two voyages in July, beginning July 17 and July 24. The company has contacted all passengers and requested they self-quarantine.

Cruise ships emerged as an early spreader of COVID-19, and almost all of the world’s cruise ships have docked as the pandemic continues. “We are now focusing all available efforts in taking care of our guests and colleagues,”  Rune Thomas Ege, Hurtigruten’s VP of communications, told USA Today. Non-European crew members were required to test negative twice before boarding, but the cruise line didn’t say if passengers were tested before boarding.