A deadly hantavirus outbreak on a luxury cruise ship marooned in the Atlantic is believed to have spread from person to person, in what would be a rare occurrence for a virus that typically spreads from rodents, health officials said.
The virus, which has been blamed for the deaths of three people as of Tuesday, may have spread by human-to-human transmission due to passengers’ close contact within the ship, the World Health Organization said at a press conference in Geneva.
“It’s definitely uncommon,” said Maria Van Kerkhove, WHO’s director for epidemic and pandemic preparedness and prevention. “WHO assesses that the overall risk to the public is low.”
Health officials are working under the assumption that the type of hantavirus involved is the Andes virus, since there is evidence, however limited, that this specific strain is capable of spreading between humans. Sequencing of the virus, which can take several days to complete, is underway in South Africa, she said.
The MV Hondius set sail from Ushuaia, Argentina, on April 1 with about 150 people of more than 20 nationalities. It traveled across the South Atlantic, with multiple stops in remote and ecologically diverse regions, including Antarctica, South Georgia, Nightingale Island, Tristan da Cunha, Saint Helena, and Ascension Island, WHO said.
One “working assumption” is that a couple who boarded the ship in Argentina and later died may have brought the virus on board. That’s partially because the Andes virus ― which WHO says can cause a severe respiratory illness that has a case fatality rate up to 50% ― is endemic to South America, said Van Kerkhove.
JEAN-PHILIPPE CHOGNOT,VALENTINA BRESCHI via Getty Images
“With the timing of the incubation of the hantavirus, which can be anywhere from one to six weeks, our assumption is that they were infected off the ship, perhaps doing some activities there,” she said. “This was an expedition boat and many of the people were doing bird-watching, they were doing a lot of things with wildlife, so our assumption is they were infected off the boat, and then joined the cruise.”
Another assumption, she said, is that other passengers picked up the virus during the ship’s visits to islands that have a lot of rodents. Human hantavirus infection is primarily acquired through contact with the urine, feces or saliva of infected rodents.
So far, there have been seven cases — two laboratory confirmed and five suspected — and three deaths. Three people with suspected cases remain on board the ship, WHO said.
The ship has been anchored off the coast of Cape Verde since Sunday, with the island nation not allowing its passengers to come ashore and passengers directed to stay in their cabins. After the medical evacuation of two people on the ship is complete, the vessel will travel to the Canary Islands, where it will be cleaned and the remaining passengers aboard the ship examined, said Van Kerkhove.
In the meantime, those aboard the ship are said to have plenty of food and water, and decontamination efforts are being carried out to limit the virus’s further spread.
“We have heard from quite a few people on the boat,” said Van Kerkhove. “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.”