Gene detective work confirms the deadly hantavirus on a cruise ship this spring spread from passenger to passenger

The hantavirus that sickened 13 passengers and killed three on the cruise ship M/V Hondius this spring passed from person to person on board after one passenger caught it from a rodent on land, according to two studies published in Science by an international team that includes the University of Geneva and Geneva University Hospitals.

The virus was genetically very close to Andes virus strains that circulate naturally in Argentina’s Patagonia region, the researchers found, which rules out rumors that it was man-made or had unusual mutations.

Why it matters

Most hantaviruses spread mainly when people breathe in dust contaminated by wild rodents’ urine, droppings or saliva.  The Andes virus is the only one known to also spread between people, usually through close, prolonged contact, according to the U.S. Centers for Disease Control and Prevention.  The studies confirm that happened on a ship full of travelers.

“The sequence of symptom onset, the genomic data, and the patterns of close contact all point to” a rodent infection followed by person-to-person spread, said Isabella Eckerle, director of the Geneva Centre for Emerging Viral Diseases.

What Bay Area residents should know

In the United States, the most common hantavirus that causes the lung disease, hantavirus pulmonary syndrome, is carried by the deer mouse, and it is not known to spread between people, the CDC says.  Symptoms usually start one to eight weeks after contact with an infected rodent:  fatigue, fever and muscle aches, followed days later by coughing and shortness of breath.  About 38% of people who develop breathing symptoms may die.

• Seal holes and gaps in your home or garage to keep rodents out.
• Set traps in and around the home, and clean up food that attracts rodents.
• If you get sick after rodent contact, see a doctor right away and mention the exposure.

How scientists traced it

The ship left Ushuaia, Argentina, on April 1, and the first case appeared April 3.  The last patient got sick May 31, 60 days after departure, far longer than the roughly six weeks it can take to fall ill after catching the virus from a rodent.  That patient had close, prolonged contact with another confirmed case.  The team also read the virus’s genetic code from 10 of the 13 patients and found nearly identical virus in all of them, a pattern that fits spread between people.  Labs in seven countries checked each other’s results.

Source:  Geneva University Hospitals news release, Nov. 13, 2026; *Science*:  Oude Munnink et al.; *Science*:  Bellomo et al.; CDC:  About Hantavirus.