Two Argentine officials looking into the origins of the outbreak said their strongest theory is that a Dutch couple visited a landfill site during their ornithological tour where they may have been exposed to rodents carrying the infection.
Scientists have said the culprit may be the long-tail pygmy rice rat, which is native to Argentina and Chile.
Measuring 20cm in length, the nocturnal rodents are known for their extremely long tails and carry the Andes variant of the hantavirus contracted by passengers.
A British crew member, 56, with a Dutch doctor, 41, and a German passenger, 65, were airlifted from the vessel on Wednesday, two of whom later tested positive.
They are being flown to receive treatment in the Netherlands. One of the flights arrived in Amsterdam with passengers being taken to hospitals for treatment.
Another stopped off in the Canary Islands to refuel after Morocco refused to let it dock.
“A patient’s isolation bubble was broken. And they stopped to fix it,” sources from the regional government’s health department said.“No person will disembark or board. It is a technical stop.”
The Spanish Health Ministry’s announcement that the ship will dock in the Canary Islands sparked a row with the islands’ regional leader, Fernando Clavijo, who said he would refuse to let it do so.
Clavijo said he was worried about the danger to the population and demanded a meeting with Pedro Sanchez, the Spanish Prime Minister.
Jorge Marichal, the president of Tenerife’s hotels association, said that competing tourist destinations such as Morocco should have “been taken into account” when considering a location for passengers to disembark.
The World Health Organisation has launched a test and trace campaign to track members of the public who may have interacted with those infected.
The South African Health Ministry said officials have traced 42 out of 62 people they believe had contact with the two infected passengers who travelled there, the Associated Press reported.
A British crew member is among three suspected hantavirus patients who have been evacuated from an infected cruise ship in Cape Verde.