Human-to-human hantavirus transmission suspected on cruise but risk to public low: WHO

GENEVA/AMSTERDAM – The World Health Organization (WHO) said on May 5 that it suspects some rare human-to-human transmission took place between close contacts on board a luxury cruise ship hit by seven confirmed or suspected hantavirus cases.

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 suspected cases are still on board the Dutch-flagged MV Hondius, one of whom only has a mild fever.

The cruise ship hit by the deadly outbreak is marooned off Cape Verde – an island nation in the Atlantic off West Africa – and not allowed to put passengers ashore.

The WHO said the focus now was to evacuate the two sick passengers still onboard to the Netherlands and then for the ship to continue to the Canary Islands.

Risk low, but transmissions do happen

Human-to-human transmission is uncommon, and the WHO reiterated that the risk to the wider public was low from a disease typically spread from infected rodents that only rarely passes between humans.

People are usually infected by hantavirus through contact with infected rodents or their urine, their droppings or their saliva.

The WHO said it had been told there were no rats on board.

However, a limited spread among close contacts has been observed in some previous outbreaks with the Andes strain, which the WHO believes could be involved in this instance.

“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,” Dr 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,” she said.

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 while on bird-watching trips to islands where birds and rodents live, as part of the cruise, it said.

The Hondius left Ushuaia in southern Argentina in March.

Anyone symptomatic on the ship and those caring for patients are wearing full personal protective equipment, with extra supplies having been brought on to the boat, Dr Van Kerkhove stated.

“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.”

Dr Van Kerkhove added that they were working hard to get people home safely.

While the WHO said the ship would be headed to the Canary Islands, Spain’s Health Ministry said it had made no decision yet on receiving it.

“Depending on the epidemiological data collected from the ship during its passage through Cape Verde, a decision will be made as to which port of call is most appropriate,” it said.

Meanwhile, Cape Verde’s National Director of Health Angela Gomes told Radio 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 was 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 (S$20,900) to €22,000.

The first stricken passenger, the Dutchman, 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”, 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.

The 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 Dutchwoman who died.

South Africa’s National Institute for Communicable Diseases is working to sequence the virus, with results possible by May 6, Dr 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 per cent, higher than average than for other strains of the virus. REUTERS