Human to human transmission is not common, and the UN 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 national have died, while a British national was evacuated from the ship and is in intensive care in South Africa, officials said. Three more people with suspected cases are still on board the Dutch-flagged MV Hondius.
The cruise ship hit by the deadly outbreak is marooned off Cape Verde, an island nation in the Atlantic off West Africa, which has not allowed the vessel to put passengers ashore.
NO RATS ON BOARD
The WHO said it had been told there were no rats on board.
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 under way.
The Hondius left Ushuaia in southern Argentina in March.
”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.
”Some people on the ship were couples, they were sharing rooms so that’s quite intimate contact,” Van Kerkhove said.
INFECTED BEFORE THE TRIP?
The U.N. 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.
Van Kerkhove said the focus now was to evacuate the two sick passengers still onboard and then for the ship to continue to the Canary Islands. The third suspected case still on board only reported a mild fever at some point.
”We have heard from quite a few people on the boat,” she said. ”We just want you to know we are working with the ship’s operators. We are working with the countries where you are from. We hear you, we know that you are scared,” she said, adding they were working hard to get people home safely.
But while the WHO said the plan was for the ship to head to the Canary Islands, Spain’s health ministry said it had made no decision yet on receiving it and that this would depend on data collected from the ship. A team of epidemiologists will carry out an inspection of the vessel in the afternoon, it said.
Meanwhile, Cape Verde’s National Director of Health Angela Gomes told Rádio de Cabo Verde that they were working on plans to evacuate the two sick people, and possibly others.
VOYAGE STARTED IN SOUTHERN ARGENTINA
Around 150 people are stuck on the Hondius, which is carrying mostly British, American and Spanish passengers 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 ($16,000 to $25,000).
The first stricken passenger, the Dutch man, died on April 11. His body remained on board until April 24, when it ”was disembarked on St Helena, with his wife accompanying the repatriation”, the ship’s operator, Oceanwide Expeditions said.
His wife, who had gastrointestinal symptoms when she was disembarked, later deteriorated during a flight to Johannesburg. She died upon arrival at the emergency department on April 26, the WHO said, adding that contact tracing was under way for passengers on that flight.
South African authorities have confirmed that the British patient, who is being treated in a Johannesburg hospital, tested positive for the hantavirus. The Netherlands has confirmed the virus in the Dutch woman who died.
South Africa’s National Institute for Communicable Diseases is working to sequence the virus, with results possible by Wednesday, Van Kerkhove said. The Institut Pasteur in Senegal is supporting efforts to test and confirm the suspected cases.
The WHO estimates that there are between 10,000 and 100,000 hantavirus cases annually. Argentina continues to have the most cases in the Americas region, the WHO said in December, with a lethality rate of around 32%, higher than average and than for other strains of the virus.
(Writing by Ingrid Melander; Reporting by Jennifer Rigby in London, Chandni Shah in Bengaluru and Charlotte Van Campenhout in Amsterdam; Additional reporting by David Latona, Toby Sterling, Julio Rodrigues, Emma Pinedo and Monica Naime; Editing by Nia Williams, Andrew Heavens and Alison Williams)
