Hantavirus outbreak on luxury cruise ship: 3 dead, critical cases in South Africa as infection reaches Switzerland

Three people have died following a hantavirus outbreak on a luxury cruise ship, while five additional cases that are confirmed or suspected have also been reported, according to a Reuters report.

However, the World Health Organization (WHO) has stated that the overall risk to public health is still considered low.

According to the ship’s operator, Oceanwide Expeditions, three passengers were evacuated on Wednesday, two of them in serious condition. One patient is currently in intensive care in South Africa, while another former passenger who returned to Switzerland is receiving treatment in Zurich, Reuters reported.

Barely 150 people are remaining on board the ship, which has been stranded off Cape Verde since Sunday and was expected to continue its journey to Spain’s Canary Islands later on Wednesday.

Passengers who are not showing any symptoms, currently all those still on the vessel—will be allowed to disembark once it reaches the Canary Islands. Spain has said that its 14 nationals will be placed in quarantine at a military hospital, while all other passengers will be repatriated and quarantined according to their respective countries’ health protocols, Reuters reported.

The strain detected on the ship has been identified as Andes hantavirus, which is usually found in Argentina and Chile. The Hondius had departed from Argentina on April 1.

The Andes virus is the only known hantavirus that can spread through close, prolonged human-to-human contact.

The WHO said on Wednesday it had not been informed of any changes in the virus that could have made it more transmissible in this way, but it believes there has been some human-to-human spread on board the Hondius, Reuters reported.

Studies have shown that the virus tends to transmit in the early stages of a patient's sickness, when they have symptoms.

Maria Van Kerkhove, WHO Director of Epidemic and Pandemic Management, told Reuters in an interview on Wednesday that close contact meant something like sharing a cabin or bunk room on board the ship. She said experts were working to establish which passengers were high-risk or low-risk, based on their contacts with passengers who were unwell.

“Symptoms typically begin one to eight weeks after exposure and may include fever, muscle aches and gastrointestinal issues, according to the WHO, although a typical incubation period would be closer to around two to three weeks,” said Andrew Pollard, a professor at Oxford University's Pandemic Sciences Institute, as reported by Reuters.

The Andes hantavirus and other hantaviruses in the Americas can cause hantavirus cardiopulmonary syndrome, which progresses quickly and leads to fluid buildup in the lungs along with heart complications. Fatality rates from hantavirus cardiopulmonary syndrome are up to 50%, the WHO says, compared to 1-15% from the infections common in Asia and Europe.

Prevention focuses on limiting contact with rodents through measures like keeping areas and surfaces clean.

During outbreaks, contact tracing can give others potentially exposed to the virus earlier access to hospital care, improving outcomes and preventing further spread.

The current outbreak is being investigated by experts from the WHO and various countries but the risk to the public remains low, the U.N. health agency says, as reported by Reuters.

Pollard said that identifying the virus responsible for the outbreak made it possible to manage the situation through public health measures on the ship, including containment and isolation, as well as through monitoring protocols in countries receiving returning passengers.

More broadly, hantaviruses continue to circulate globally, with the WHO warning about a rise in cases across the Americas in late 2025.

(With inputs from Reuters)