May 5 (UPI) — The hantavirus that has killed three and sickened others on board a cruise ship is believed to be a variant that transmits from human to human, World Health Organization officials have said.

Hantavirus strains found in the Americas have an up to 50% fatality rate, the WHO said, and the Andes version, found mostly in South America, has been shown to have limited human‑to‑human transmission. The WHO suspects that the people infected on the cruise ship MV Hondius have the Andes strain.

The ship, which is carrying nearly 150 people, including passengers and crew, is moored off the coast of Cape Verde, which is in the Atlantic Ocean, off the coast of Senegal. It was denied permission to dock in Cape Verde, but a few ill people have been airlifted from the boat. There are 17 Americans on board.

“We do know that some of the cases had very close contact with each other and certainly human-to-human transmission can’t be ruled out, so as a precaution, this is what we are assuming,” CNN reported Dr. Maria Van Kerhove, WHO’s director for epidemic and pandemic preparedness and prevention, told reporters.

“The risk to the general public is low,” Van Kerkhove said. “This is not a virus that spreads like flu or like COVID. It’s quite different.”

There are seven cases total: two confirmed and five suspected.

A Dutch man, 70, died on the ship on April 11, and his cause of death wasn’t known. His wife, 69, also Dutch, disembarked at St. Helena in the South Atlantic to escort his body home. In Johannesburg, South Africa, the woman collapsed and died soon after arriving at a hospital.

Authorities are conducting contact tracing for those on the flight to Johannesburg.

The couple had traveled in Argentina before boarding the cruise on April 1.

On April 24, a British man told the ship’s doctor he was ill. He was evacuated from Ascension Island in the South Atlantic to South Africa, where he is in intensive care. Van Kerkhove said his condition is improving.

An adult German woman with pneumonia died on May 2.

Three suspected cases have reported high fever or gastrointestinal symptoms and are still on board. Medical teams in Cape Verde are evaluating the patients and collecting specimens for testing. Two are being evacuated, Van Kerkhove said.

Travel vlogger Jake Rosmarin is aboard the ship and spoke of the fear and uncertainty on the ship Monday.

“What’s happening right now is very real for all of us here. We’re not just a story. We’re not just headlines,” he said in a video posted on Instagram.

Once the ill people are evacuated, the ship will travel to the Canary Islands, where Spanish authorities will do a full epidemiological investigation and full disinfectation, Van Kerkhove said.

The hantavirus strain found in the United States — mostly in the southwest — is transmitted by contact with rodents.

The MV Hondius is part of Oceanwide Expeditions, which is based in the Netherlands.