An Argentine fishing boat that had been at sea for 35 days returned to land when some of its 61 crew showed symptoms of the new coronavirus, Tierra del Fuego Province's Health Ministry reported on Monday.
Reports later that evening from local outlets said that 57 of the crew members had tested positive for Covid-19. The Ushuaia 24 news portal said that all of them remain isolated on the ship, the Etchizen Maru, and that they would not be allowed to disembark. Only medical personnel would be allowed to board, it added.
The incident has attracted attention since prior to setting sail the 60 crew members had completed 14 days of mandatory quarantine in a hotel in Ushuaia, and before that they had been swabbed with a negative result, according to a statement from the Tierra del Fuego health portfolio, in the southern tip.
"It is difficult to establish how the contagion of this crew was, since in these 35 days they have not had contact with land and the supply is made only when leaving the port of Ushuaia," said Alejandra Alfaro, the director of the province's Atención Temprana de Salud centre.
He explained that they are studying "what the chronology of symptoms has been like within the crew to establish the contagion timeline."
Leandro Ballatore, chief of infectology at the Ushuaia Regional Hospital, warned that "it is a case that escapes all the description that appears in the publications, because such a long incubation period is not described anywhere."
The Etchizen Maru returned to the port of Ushuaia when the first crew-members began showing symptoms of Covid-19 onboard, so the emergency protocol was activated and the crew was placed in mandatory isolation on board the vessel.
"We cannot yet explain how the symptoms appear. It is somewhat striking, but we are handling five hypotheses that we have to finish evaluating to establish what happened," said Ballatore, a member of the province's Emergency Operations Committee.
The Argentine Naval Prefecture maintains a security cordon around the boat to prevent "nobody getting on or off without permission," said Alfaro.
The Etchizen Maru belongs to a firm called Pesantar, a part of the New San group, one of the main manufacturers of electronic products in the province.
Argentina exceeded 100,000 coronavirus cases on Sunday, with fatalities totalling 1,859 to date. Around 95 percent of infections have occured in the Buenos Aires Metropolitan Area, with a population of 14 million out of 44 million Argentines.
Domestic tourism re-opened in Tierra del Fuego in late June, after more than a month of no new cases. Since the start of the pandemic, there have been only 141 cases and one death in the province. Of those infected, only five still have the virus, as of Friday.