WHO races to contain first cruise ship hantavirus outbreak

World health authorities are drafting emergency containment protocols after the Andes strain of hantavirus killed three people and infected at least eight aboard a cruise ship — the first recorded outbreak of the disease at sea, The Korea Times reported Thursday. About 150 passengers are expected to disembark in Tenerife on Sunday.

The Andes virus can kill up to half of those it infects, and no approved vaccine or specific antiviral exists. With the ship's arrival imminent, experts say timely contact tracing and social distancing — lessons drawn from Argentina's 2018-19 outbreak — are the only tools available to break the chain of transmission.

Abdi Rahman Mahamud, director of WHO's Alert and Response Coordination Department, said authorities can stop the outbreak if they act on proven methods. "If we follow public health measures and the lessons we learned from Argentina ... we can break this chain of transmission. This doesn't need to be a large epidemic," Mahamud said, according to The Korea Times.

Health officials are implementing contact tracing, isolating symptomatic patients and anyone potentially exposed, classifying contacts by risk level, and requiring daily temperature checks for a minimum of 42 days — the Andes virus's maximum incubation period. The United Kingdom government said it is flying its nationals home under infection control measures, with a 45-day quarantine upon return.

The Andes strain is the same one that caused an outbreak in Argentina from 2018 to 2019, infecting 34 people and killing 11. Gustavo Palacios, a professor at the Icahn School of Medicine at Mount Sinai, said that episode offers a model for the current response. "We essentially learned that once you implement basic measures of social distancing, that are essentially very simple – stay home when you are not feeling well – that diminished the circulation and the outbreak burned out," Palacios told The Korea Times.

Krutika Kuppalli, associate professor of medicine at the University of Texas Southwestern Medical Center and a former WHO mpox protocol specialist, said existing epidemiological frameworks remain valid regardless of the novel setting. "It's the same principle as for measles, or Ebola. Contact tracing doesn't change," Kuppalli said.

No passengers currently aboard are showing symptoms, The Korea Times reported. The virus spreads through close, prolonged contact with symptomatic individuals — a trait that makes the ship's confined quarters a particularly challenging environment. WHO Technical Officer Anais Legand is among the experts working to finalize guidance before the vessel docks in Tenerife.

The outbreak marks the first time hantavirus has been officially recorded spreading aboard a ship, forcing public health frameworks developed for land-based settings to be adapted for a maritime environment with no established precedent.