A deadly outbreak of hantavirus aboard an expedition cruise ship has set off an international public health response, with health authorities across more than a dozen countries scrambling to track down passengers who may have been exposed to the rare and potentially fatal virus.
The MV Hondius, owned by Dutch company Oceanwide Expeditions, departed from Ushuaia, Argentina the southernmost city in the world on April 1, carrying roughly 150 passengers and crew members from 23 different nationalities. What began as an expedition voyage toward Antarctica and isolated South Atlantic islands has since become the focus of a global health investigation.
How the outbreak unfolded
A 70 year Dutch man began showing symptoms on April 6 and died on board the ship on April 11. At the time, his death was attributed to general natural causes. It was only weeks later that the full picture came into focus.
His body was not removed from the ship until April 24, when it arrived at Saint Helena, a British Overseas Territory. At that point, passengers disembarked including the man’s 69 year old widow, who later flew to South Africa. The ship operator reported that approximately 30 passengers disembarked, while Dutch officials put the number closer to 40.
The World Health Organization has since confirmed eight cases linked to the vessel, with three passengers now dead. Passengers from 12 countries disembarked the ship at its St. Helena stop, and the cruise ship’s operator confirmed that 30 individuals from at least that many countries had left the vessel before the outbreak was publicly known.
On May 6, it was confirmed that the Andes virus normally found in South America was responsible for the outbreak.
What is the Andes virus and why does it matter?
Hantavirus is a term used to describe a family of viruses that can cause either hemorrhagic fever with renal syndrome or hantavirus pulmonary syndrome. In the Americas, these viruses typically cause pulmonary syndrome, while strains found in Africa, Asia and Europe generally cause the renal form. The case fatality rate for hantavirus pulmonary syndrome is approximately 40% among those who develop severe disease.
What makes the Andes strain especially concerning is a characteristic that sets it apart from virtually every other hantavirus known to science.
Most recorded hantavirus cases are contracted through direct exposure to rodents and their feces and urine not through human to human transmission. The Andes virus is the exception. The recent outbreak has drawn attention because this strain appears to transmit more readily from person to person than other hantaviruses, through exchanges of bodily fluids associated with close contact, including respiratory droplets though this is generally considered distinct from true airborne transmission. A confined space such as a cruise ship cabin, especially among family members, can present a higher risk.
Spread on board the MV Hondius has been at least partially attributed to human to human transmission. Earlier outbreaks in Argentina have included a super spreader event where a single introduction of the virus led to 34 infections.
Symptoms to watch for
Early symptoms of hantavirus infection are generally flu like, including fatigue, muscle aches and fever, as well as possible dizziness and gastrointestinal symptoms such as abdominal pain, nausea and diarrhea. These initial symptoms typically begin one to eight weeks after exposure. Four to ten days after onset, hantavirus pulmonary syndrome can become more severe, with coughing and shortness of breath rapidly progressing to respiratory failure.
Where things stand now and who is being monitored
Passengers from the MV Hondius hail from Australia, Belgium, France, Greece, Guatemala, India, Ireland, Japan, Montenegro, New Zealand, Poland, Portugal, Russia and Turkey, among other nations. Seventeen of the ship’s passengers are from the United States, and authorities in at least five states Arizona, California, Georgia, Virginia and Texas are monitoring previous passengers, none of whom have shown symptoms so far.
A Swiss man who returned home after the voyage tested positive for the Andes strain and is being treated at University Hospital Zurich. His wife, who accompanied him on the trip, has not yet shown symptoms but is self isolating as a precaution.
The Argentine health ministry has been advancing an epidemiological investigation, capturing and testing rodents along the route the first victim traveled during a four-month road trip through Chile, Uruguay and Argentina, which ended just four days before the ship’s departure.
The wider concern research cuts and preparedness
The outbreak has also reignited debate about public health preparedness. In 2025, the Trump administration eliminated funding for a group that had been running a pilot project aimed at studying how hantavirus passes from rodents to humans. The project was part of the Centers for Research in Emerging Infectious Diseases. Experts have warned that such cuts make the U.S. and the world more vulnerable to viral pandemics, pointing to the Zika outbreak of 2015 and 2016 as a cautionary example of what can happen when a previously obscure pathogen spreads widely before it is well understood.
There is currently no vaccine or targeted antiviral treatment for hantavirus. The WHO’s director general has classified the MV Hondius situation as serious but maintains that the overall public health risk remains low, as the Andes virus does not appear to pass between humans easily. Health authorities are urging anyone who traveled on the ship to monitor themselves closely and report any symptoms immediately
