The World Health Organisation says it suspects some rare human-to-human transmission of the deadly hantavirus has taken place between very close contacts on board a luxury cruise ship hit by seven confirmed or suspected cases.
Human-to-human transmission is not common, and the United Nations health agency reiterated that the risk to the wider public was low from a disease typically spread from contact with infected rodents.
A Dutch couple and a German citizen have died while a UK passenger was removed from the ship and is in intensive care in South Africa, officials said.
Two crew members require urgent medical care, the Dutch-flagged MV Hondius ship’s operator Oceanwide Expeditions said.
Another person on board with a suspected case has only reported a mild fever.
The Dutch foreign ministry said it was preparing to move three people from the ship to the Netherlands.
It was not yet clear when or where the nearly 150 other people still onboard would disembark.
The cruise ship hit by the deadly outbreak is moored off Cape Verde.
The island country in the Atlantic off west Africa was meant to be its final destination but it has not allowed the vessel to put passengers ashore because of the outbreak.
People are usually infected by hantavirus through contact with infected rodents or their urine, their droppings or their saliva.
However, a limited spread among close contacts has been observed in some previous outbreaks with the Andes strain, which spreads in South America, including Argentina, and which the WHO believes could be involved in this instance.
Testing is ongoing.
The Hondius left Ushuaia in southern Argentina in March.
The WHO said it had been told there were no rats on board.
“We do believe that there may be some human-to-human transmission that’s happening among the really close contacts, the husband and wife, people who have shared cabins,” Maria Van Kerkhove, the director of epidemic and pandemic preparedness and prevention at the WHO, told reporters in Geneva.
Van Kerkhove said the focus was now to relocate the two sick passengers still onboard and then for the ship to continue to the Canary Islands.
But later in the day, Spain’s health ministry said it saw no need for the ship to make a stop in the Canary Islands if everyone who was sick was removed in Cape Verde, unless new cases emerged.
The UN health body said its working assumption was that in the initial cases of the Dutch couple, who joined the ship in Argentina after travelling in the country, they were infected before joining the cruise.
Other cases may also have been infected whilst on bird-watching trips to islands where birds and rodents live as part of the cruise, it said.
The Hondius is carrying passengers mostly from the United Kingdom, United States and Spain on a luxury cruise that set off from the southern tip of Argentina in late March.
The cruise visited the Antarctic peninsula and South Georgia and Tristan da Cunha – some of the remotest islands on the planet.
The voyage was marketed as an Antarctic nature expedition, with berth prices ranging from 14,000 to 22,000 euros ($A22,000 to $A35,000).
South Africa’s National Institute for Communicable Diseases is working to sequence the virus, with results possible by Wednesday, Van Kerkhove said.
