KLM Airlines on Wednesday issued an advisory saying the woman had also briefly been aboard one of their flights from Johannesburg to Amsterdam on 25 April before the crew decided not to let her fly due to her medical condition.
The third fatality – a German woman – is not a confirmed case either. Her body remains on the ship.
Dr Van Kerkhove said the way hantavirus is transmitted “is very different than COVID and flu”.
“We’re not talking about casual contact from very far away from one another,” she said, but “really physical contact”.
A total of 146 people from 23 different countries remain aboard the MV Hondius under “strict precautionary measures”, Oceanwide Expeditions said.
They have been joined by infectious disease experts and WHO staff, who will travel with them to the Canary Islands.
All those who remain on the ship have no symptoms, Spain’s health minister Mónica García said.
She added that everyone on board will undergo a medical assessment when they arrive in Tenerife and, if fit to travel, those from abroad will be repatriated to their home countries.
Spaniards, meanwhile, will be sent to a defence hospital in Madrid to quarantine.
The evacuation would “avoid contact” with Canary Island citizens and that there would be “no risk” to them when it arrives in Tenerife in the coming days, Garcia said.