The index case no one expected
Andes hantavirus belongs to the forests of southern Argentina and Chile. Its natural host, the long-tailed pygmy rice rat, has never been found outside South America. Yet in April 2026 the virus surfaced aboard a cruise ship crossing the Atlantic — thousands of kilometres from any known reservoir. The question that drove the investigation was simple: how?
Argentine officials now believe a Dutch couple — a 70-year-old man and his 69-year-old wife — contracted the virus during a birdwatching excursion near a landfill outside Ushuaia before boarding the MV Hondius on 1 April. The couple had spent months crossing between Argentina, Chile and Uruguay, passing through Neuquén and Misiones — both WHO-designated Andes virus endemic zones. Teams from the Malbrán Institute are trapping and testing rodents along their entire route.
Why a cruise ship changed the equation
Andes virus is the only hantavirus known to pass between humans, but even that requires close, sustained contact — sharing meals, bedding, breathing the same confined air during the prodromal phase. On land, this limits chains to household clusters. The 2019 Epuyén outbreak in Patagonia showed what happens when conditions align: a single introduction chained through 34 people in a small town, killing 11.
The MV Hondius created a floating Epuyén. One hundred and fifty people from 23 countries shared dining rooms, corridors and lounges for weeks. By the time the first death occurred on 11 April, the virus had already had five days to spread through close contacts. And because the death was attributed to natural causes — hantavirus was not suspected on a North Atlantic ship — no isolation measures were taken for another three weeks.
The victims
Three people died. The Dutch man fell ill on 6 April with fever, headache, abdominal pain and diarrhea. He died aboard the ship on 11 April. His wife disembarked at Saint Helena on 24 April, flew to South Africa, deteriorated during the Johannesburg flight, and died shortly after arrival. KLM later notified passengers on her connecting flight. A German national also died; details remain undisclosed.
Global dispersal
By the time WHO was notified on 2 May, approximately 30 passengers had already disembarked at Saint Helena and scattered across continents. Contact tracing now spans the United Kingdom (3 nationals under UKHSA care), Germany (1 confirmed death), Switzerland (1 hospitalised in Zurich), the Netherlands (index case country, KLM passengers notified), Singapore (2 residents isolated after a shared Johannesburg flight), the United States (17 Americans still aboard, returnees monitored in 5+ states), Canada, Belgium, South Africa and others.
The ship departed Cabo Verde on 6 May heading for the Canary Islands. Spain approved docking at Tenerife after initial resistance from the islands' president. Passengers will transfer directly to the airport. The 17 Americans will be quarantined at the National Quarantine Unit at the University of Nebraska Medical Center.
Current numbers
Case count (May 2026)
- Deaths: 3 (2 Dutch, 1 German)
- Confirmed: 5 (PCR Andes virus)
- Suspected: 3 (awaiting lab confirmation)
- People on board: 147 from 23 countries
- Countries with active cases or monitoring: 14+
WHO risk assessment
- Global public: Low
- Returned passengers: Low with active monitoring
- Healthcare workers: Low with standard precautions
- Future travellers: Very low