A hantavirus outbreak on a cruise ship in the Atlantic Ocean has raised questions about how the rare, often fatal illness could have spread among passengers and crew, and whether it may continue to infect some of the 150 people now stranded aboard the vessel.
There have been at least eight suspected or confirmed cases tied to the cruise ship, including three deaths.
While typically transmitted to humans through contact with contaminated rodent waste, the strain of hantavirus detected in passengers on the cruise has been passed between people before, albeit on a very limited basis. The origin of the outbreak remained unclear.
“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’ve shared cabins,” said Maria Van Kerkhove, the World Health Organization’s director of epidemic and pandemic preparedness and prevention, at a news conference Tuesday. She was referencing a couple who died from suspected hantavirus cases after spending time on the MV Hondius, a Dutch ship that became the focal point of the apparent outbreak while charting a weekslong polar expedition.
Van Kerkhove suggested the husband and wife may have contracted the virus while exploring wildlife in Argentina, before they joined the cruise. She said the U.N. health agency is generally operating under the assumption that the virus came from outside of the ship.
“The cruise did stop at many different islands up the coast of Africa, and, again, seeing a lot of different wildlife on those islands. There are birds. Some islands have a lot of rodents. Others don’t,” said Van Kerkhove. “So, there could be some source of infection on the islands as well for some of the other suspected cases.”
One known hantavirus strain spreads between people
Hantaviruses are a family of diseases that can cause severe respiratory symptoms, and even death, in people worldwide, according to the U.S. Centers for Disease Control and Prevention. People usually contract the virus only after coming in contact with airborne particles from rodent droppings, urine or saliva.
But on Wednesday, the WHO confirmed that the virus in the cruise ship outbreak was of the Andes strain. As the agency previously said, that specific strain is the only variation of hantavirus with previously reported instances of human-to-human transmission, and it is also responsible for most cases of the illness in South America.
The largest outbreak of the Andes strain was in Argentina in 2018, leading to 34 cases and 11 deaths, said CBS News medical correspondent Dr. Céline Gounder. The Argentinian province that includes Ushuaia, where the ship departed on April 1, has never reported a hantavirus case, according to Gounder, suggesting the possibility that it might have been encountered on a stop or excursion elsewhere.
Human-to-human transmission requires “prolonged close contact,” she said, adding, “this is not a pandemic kind of virus.”
“That also raises the question of whether multiple passengers were exposed to the same contaminated environment, which would mean some of the cases may not be person-to-person spread at all,” Gounder said.
She emphasized that hantavirus remains rare, with fewer than 900 cases over 30 years in the U.S.
The cruise operator, Oceanwide Expeditions, said a 70-year-old Dutch man died on board the ship on April 11. The man’s 69-year-old wife died about two weeks later in South Africa, after disembarking the ship. Her condition had “deteriorated during a flight to Johannesburg,” officials said. According to South Africa’s Health Ministry, the wife’s blood tested positive for the Andes strain of the hantavirus.
A British passenger evacuated from the Hondius to South Africa on April 27 also tested positive for the Andes strain, authorities said, and health officials have described him as critically ill.
On Wednesday, a Swiss man who had been on the ship tested positive for the Andes strain and is receiving care, authorities there announced.
Another suspected case was a fatal infection in a German passenger whose body was still on board the ship, WHO said. Three others — Dutch, German and British nationals — were evacuated from the ship Wednesday to be treated by specialists in The Netherlands, officials said.
The ship has been anchored off the island of Cape Verde off Africa’s west coast for days. Cape Verde sent medical teams to assist the Hondius crew but prevented the ship from docking at its ports because of health concerns.
AFP via Getty Images
Ann Lindstrand, a WHO representative for Cape Verde, sought to assuage fears of cruise ships, which are seldom linked to hantavirus despite being frequent sites of other kinds of disease outbreaks, like norovirus. Asked to what extent hantavirus is a pandemic-level threat, she said: “It’s not.”
“We hear you”
The ship had been expected to make its way toward Spain’s Canary Islands after the sick passengers were evacuated, for a “full inspection” and “full disinfection,” but the leader of the regional government there rejected the idea Wednesday, once again leaving passengers trapped at sea.
The passengers and crew could potentially be kept on board for up to eight weeks, said Lindstrand, since the virus’ incubation period can be that long. However, she acknowledged the psychological toll such “distressing” circumstances could take.
One passenger, travel blogger Jake Rosmarin, touched on that in an emotional social media video shared Monday, saying, “There’s a lot of uncertainty, and that’s the hardest part. All we want right now is to feel safe, to have clarity and to get home.”
Officials recognized that the situation is frightening for those on the ship.
“We have heard from quite a few people on the boat,” said Van Kerkhove at Tuesday’s news conference. “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.”