Hantavirus Outbreak on Cruise Ship: Origins, Spread, and What Happens Next

Deadly Hantavirus Outbreak Strikes Cruise Ship Passengers

A dangerous hantavirus outbreak has gripped the Dutch-flagged cruise ship MV Hondius, leaving three passengers dead and health authorities across multiple countries scrambling to contain the situation. As the vessel makes its way toward the Canary Islands, public health officials are working around the clock to trace contacts, sequence the virus's genome, and prevent further spread.

How the Outbreak Unfolded

The first cases emerged in April aboard the MV Hondius, which was sailing from Argentina to Cape Verde. Affected passengers reported a range of serious symptoms, including high fever, gastrointestinal distress, pneumonia, acute respiratory distress syndrome, and circulatory shock. By Thursday, eight suspected cases had been identified, with five laboratory-confirmed as hantavirus.

Among the victims was a Dutch couple — the man died onboard and his body was removed at Saint Helena, though he was never tested for the virus. His wife later fell ill during a flight to Johannesburg and died upon arriving at a hospital there, where tests confirmed hantavirus infection. Authorities are now tracing all individuals who came into contact with her along the way.

A German woman who also died remains onboard the ship. A male passenger evacuated from Ascension Island to South Africa is receiving intensive care and is reportedly showing signs of improvement. He too tested positive for the virus.

A Swiss resident who had disembarked at Saint Helena later sought medical attention in Zurich after developing symptoms and has since been confirmed as a hantavirus case. Three additional patients were evacuated to the Netherlands for treatment, including a Dutch crew member, a German woman who was subsequently transferred to Düsseldorf, and Martin Anstee, a 56-year-old retired British police officer who served as an expedition guide aboard the ship. Anstee is currently hospitalized in Leiden.

On Thursday, a flight attendant in Amsterdam who had contact with the woman who died in South Africa came forward reporting potential symptoms. Two British nationals who disembarked at Saint Helena in late April have returned to the UK and are self-isolating, though neither has reported symptoms to date.

What Is Hantavirus and How Does It Spread?

Hantaviruses belong to a broad family of viruses that naturally circulate in rodent populations, including mice and rats. Different strains exist across the globe, each associated with specific rodent hosts. Humans typically become infected by inhaling droplets or contaminated dust particles carrying the urine, feces, or saliva of infected animals.

The disease presents in two primary forms depending on geographic origin. Strains found in Europe and Asia — known as Old World hantaviruses — tend to cause hemorrhagic fever with renal syndrome (HFRS), a kidney-affecting illness with a fatality rate of around 10%. New World strains, originating in the Americas, are considerably more lethal, causing hantavirus pulmonary syndrome (HPS), which can kill more than one in three infected individuals.

Why This Strain Is Particularly Concerning

While most hantavirus strains do not transmit between humans, the Andes strain — identified as the cause of this outbreak — is a notable exception. Endemic to Argentina, the Andes strain is hosted by the long-tailed pygmy rice rat and has a documented history of person-to-person transmission, typically through prolonged, close contact during the early stages of illness.

A previous outbreak in Argentina between 2018 and 2019 offers a sobering comparison: three individuals infected through contact with rodents went on to transmit the virus to 34 others, 11 of whom died.

Tracing the Source of the Outbreak

Public health investigators are compiling detailed travel histories for all passengers who were aboard the MV Hondius prior to the voyage. WHO Director-General Dr. Tedros Adhanom Ghebreyesus confirmed that the Dutch couple — believed to be the index cases — had traveled through Argentina, Chile, and Uruguay on a birdwatching excursion before boarding. Their itinerary included visits to locations known to be habitats of the rat species associated with the Andes strain.

Three laboratories — located in South Africa, Switzerland, and Senegal — are currently sequencing the full genome of the virus. Results will be compared against genomic data from previous outbreaks, including the 2018–19 Argentine cases, to determine whether any mutations have occurred.

Anaïs Legand, the WHO's technical lead on viral hemorrhagic fevers, noted: "It will give us a sense of whether we are seeing some changes." Infectious disease epidemiologist Maria van Kerkhove added that while nothing unusual has been detected so far, experts continue to monitor the situation closely.

What Comes Next for Passengers and Crew

The MV Hondius is expected to dock in Tenerife, Canary Islands, this weekend. Approximately 19 British nationals still onboard are set to be repatriated on a charter flight arranged by the UK Foreign Office, provided they remain symptom-free. Upon returning to the UK, they will be required to self-isolate for 45 days, a precaution that reflects the virus's lengthy incubation period — most symptoms appear between one and six weeks after exposure.

Given this extended window, health officials acknowledge that additional cases could emerge among passengers, crew members, or close contacts of those who have already left the ship. However, both the UK Health Security Agency and the WHO have emphasized that the broader public risk remains low.

"This is not Covid, this is not influenza — it spreads very, very differently," said Kerkhove, underscoring the importance of keeping the outbreak in proper perspective while remaining vigilant.