What is hantavirus and how did it kill cruise ship passengers?

A cluster of hantavirus infections linked to a cruise ship in the Atlantic Ocean has left three people dead and several others seriously ill, prompting an alert from the World Health Organization and raising questions about how a rare rodent-borne disease might spread in such an unusual setting.

The outbreak occurred aboard the Hondius, a polar expedition vessel that had been sailing from Argentina toward Europe. Passengers and crew developed severe respiratory symptoms, with some evacuated to hospitals in South Africa. Authorities are still investigating how the virus was transmitted on board.



Here’s what to know about hantavirus and the risks posed by this outbreak.

What is hantavirus?

Hantaviruses are a group of viruses carried by rodents that can cause severe disease in humans. Depending on the strain, they can trigger hantavirus pulmonary syndrome, which affects the lungs, or hemorrhagic fever with renal syndrome, which affects the kidneys. Though infections are rare, they can be severe. Some forms of hantavirus pulmonary syndrome have fatality rates of up to 40% or higher.

What do we know about the hantavirus outbreak on the cruise ship?

The outbreak has been linked to the Hondius, which was carrying roughly 150 passengers on a voyage that included stops in Antarctica and remote South Atlantic islands.

The first known case involved a 70-year-old passenger who developed symptoms including fever and gastrointestinal illness before dying as the ship neared the island of St. Helena. His 69-year-old wife later fell ill and died in a hospital in South Africa, while the AFP reported the body of a third victim was still on board the ship. Another passenger is in intensive care in Johannesburg, while additional suspected cases are under investigation.

Two crew members also require urgent medical care, according to the ship’s operator, Oceanwide Expeditions BV. As of 11 p.m. Central European Time on May 3, Cape Verdean authorities had yet to approve disembarkation for sick passengers or wider medical screening, the Dutch company said.

How does hantavirus spread?

The virus is primarily transmitted from rodents to humans. Infection usually occurs when people inhale particles contaminated with rodent urine, droppings or saliva, often in enclosed or poorly ventilated spaces. It can also spread through direct contact with contaminated materials or, more rarely, rodent bites.

Human-to-human transmission is extremely uncommon, though one strain known as Andes hantavirus — found in South America — has been shown to spread between people in limited outbreaks.

That makes the cruise ship cluster unusual, since exposure is more often linked to rural or outdoor environments where people encounter rodent habitats.

What are the symptoms?

Early symptoms often resemble the flu, including fever, fatigue, muscle aches and headaches. Patients may also experience nausea, vomiting and abdominal pain.

In severe cases, symptoms can rapidly progress to respiratory distress as fluid builds up in the lungs, a hallmark of hantavirus pulmonary syndrome. Patients may require intensive care, including oxygen support or mechanical ventilation.

The incubation period can range from about one to eight weeks after exposure.

Why is this outbreak concerning?

antavirus infections are rare and typically occur in isolated cases rather than clusters, especially in controlled environments like ships.

The outbreak raises questions about where exposure occurred — whether earlier in the voyage, such as during land excursions, or on the vessel itself. Investigators are working to trace contacts and determine the virus strain through genomic sequencing.

The confined setting of a cruise ship also complicates response efforts, including isolating patients, evacuating the sick and preventing further spread.

The disease drew wider public attention last year after Betsy Arakawa, the wife of actor Gene Hackman, died from hantavirus pulmonary syndrome in New Mexico. Hackman died days later from heart disease, with Alzheimer’s disease a contributing factor, officials said.

Is there a treatment or vaccine?

There is no specific antiviral treatment or widely available vaccine for hantavirus infections. Care is largely supportive, focusing on managing symptoms and complications such as low oxygen levels or organ failure.

Early medical attention improves outcomes, particularly for severe respiratory cases.

What happens next?

The WHO said it is coordinating with national authorities and the ship’s operator to manage the outbreak, including medical evacuations and risk assessments for passengers and crew.

Further updates are expected as laboratory testing confirms additional cases and investigators determine how the virus spread. The findings could shape how health officials assess risks in similar travel settings in the future.