A luxury expedition cruise. Penguins, Antarctic ice, remote Atlantic islands. For the 170 or so passengers aboard the MV Hondius in early 2026, this was the trip of a lifetime. What nobody could have anticipated was that the voyage would become the center of an urgent international health investigation, with three people dead, others critically ill, and 149 passengers stranded offshore while the world tried to understand what was happening on board.
The disease suspected at the center of it all is one most people have never given much thought to. It is not a new pathogen, and it is not spread through human contact in the way most respiratory illnesses are. It comes from rodents. And yet, in the right circumstances, it can kill nearly four in ten people it infects.
This is what we currently know about hantavirus, the MV Hondius outbreak, how to recognize the disease, and what to do if you think you have been exposed.
What We Know
Testing confirmed hantavirus as the source of infection in two patients, according to the World Health Organization, which assessed the ongoing risk to the general public as low, noting the disease is rare in humans and not easily transmitted. Three people died and at least three others became seriously ill in the suspected outbreak aboard the MV Hondius, a cruise ship operated by Oceanwide Expeditions, which was anchored off Praia, the capital of Cape Verde, in the Atlantic Ocean. The remaining passengers, representing 23 different nationalities, were required to follow strict precautionary measures including isolation and medical monitoring.
The outbreak raised immediate scientific questions: How did hantavirus appear on an ocean-going vessel? What does it do to the human body? And critically, what should everyone know about identifying and responding to it?
The MV Hondius Outbreak: A Timeline
The Ship and Its Route
The Hondius left Ushuaia in southern Argentina in March, on a voyage marketed as an Antarctic nature expedition, with berth prices ranging from 14,000 to 22,000 euros. According to the ship-tracking site MarineTraffic, the Dutch-flagged passenger vessel made stops in Antarctica before returning to Ushuaia and leaving again on April 1. It then stopped at the British overseas territory of Saint Helena before anchoring off Praia.
Cases, Deaths, and Nationalities
Two of the deceased victims were a married couple: a 70-year-old man who died on board on April 11 and was declared dead on arrival to the remote Atlantic island of St. Helena on April 24, and a 69-year-old woman who collapsed at Johannesburg’s international airport while attempting to fly back to the couple’s native Netherlands. A British man being treated in a private clinic in Johannesburg became ill on April 27, while a German national on the ship died on May 2. The cause of the German victim’s death had not been confirmed at time of reporting by Oceanwide Expeditions.
There were 149 people on the ship at the time, representing 23 different nationalities, including 88 passengers and 61 crew members. Seventeen passengers were Americans. Global Affairs Canada confirmed in an email to CBC News that Canadian consular officials were in contact with local authorities and that there were no reports of Canadians being directly affected by the outbreak.
The WHO Assessment
As of May 4, 2026, seven cases, including two laboratory-confirmed cases of hantavirus and five suspected cases, had been identified, including three deaths, one critically ill patient, and three individuals reporting mild symptoms. Detailed investigations were ongoing, including further laboratory testing and epidemiological work. Medical care and support were being provided to passengers and crew. Sequencing of the virus was also underway.
Health authorities emphasized that the outbreak did not represent a public health threat. “The risk to the wider public remains low. There is no need for panic or travel restrictions,” said Hans Kluge, WHO’s regional director for Europe, adding that hantavirus infections were “uncommon and usually linked to exposure to infected rodents.”
Why a Ship? The Unanswered Question
The biggest question surrounding the MV Hondius outbreak is epidemiological: how did multiple passengers aboard an ocean vessel contract a virus that normally requires direct contact with infected rodents on land?
Dr. Scott Miscovich, a family physician and president and CEO of Premier Medical Group, told CNN he found it highly unusual for a hantavirus outbreak to occur on a ship. “When I first read this, I thought that they were making a misprint,” he said. He identified two plausible explanations: the ship could have become contaminated with rat or mice feces or urine, or one of the passengers could have picked up the Andes variant of hantavirus through the limited human-to-human transmission pathway it is known to allow.
A Cambridge epidemiologist noted there were multiple possible scenarios, including the possibility that rodents are not uncommon passengers on ships. The comment came from Dr. Charlotte Hammer, an assistant professor and epidemiologist at the University of Cambridge, who was quoted in coverage of the outbreak.
The ship left Argentina, where hantavirus is endemic, several weeks earlier, although Argentine health officials reported no known cases of the virus in the area at the time of departure, according to the New York Times.
What Hantavirus Actually Is
Hantaviruses are a family of viruses that can cause serious illnesses and death. These viruses cause diseases like hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS). They are spread mainly by rodents.
Studies indicate hantaviruses have been around for centuries, with outbreaks documented in Asia and Europe. In the Eastern Hemisphere, the virus has been linked with hemorrhagic fever and kidney failure. It was not until the early 1990s that a previously unknown group of hantaviruses emerged in the southwestern United States as the cause of an acute respiratory disease now known as hantavirus pulmonary syndrome.
Hantavirus disease surveillance in the United States began in 1993 during an outbreak of severe respiratory illness in the Four Corners region, the area where Arizona, Colorado, New Mexico, and Utah meet. Hantavirus pulmonary syndrome became a nationally notifiable disease in 1995.
Two Distinct Syndromes
According to the CDC, hantaviruses cause two serious syndromes: hantavirus pulmonary syndrome (HPS), a severe disease that affects the lungs, and hemorrhagic fever with renal syndrome (HFRS), a severe disease that affects the kidneys.
HPS receives the most attention because it has a fatality rate of about 40 percent. The death rate for HFRS varies from 1 percent to 15 percent of patients, according to the CDC. Authorities had not confirmed which of the two syndromes spread on the cruise ship, but pulmonary hantavirus was believed to be responsible, according to international media reports.
As of the end of 2023, 890 cases of hantavirus disease had been reported in the United States since surveillance began in 1993. These were all laboratory-confirmed cases and included both HPS and non-pulmonary hantavirus infection.
How Hantavirus Spreads
Rodent-to-Human Transmission
People get hantavirus from contact with rodents like rats and mice, especially when exposed to their urine, droppings, and saliva. It can also spread through a bite or scratch by a rodent, but this is rare.
The most dangerous moment is not the rodent sighting itself. Humans often become infected when they inhale particles from dried rodent droppings. Typically, this happens when someone attempts to dispose of rodent droppings by sweeping them up, causing the particles to become airborne.
Hantavirus is mainly spread by contact with rodents or their urine, saliva, or droppings, particularly when the material is disturbed and becomes airborne. People are typically exposed to hantavirus around their homes, cabins, or sheds, especially when cleaning out enclosed spaces with little ventilation or exploring areas where there are mouse droppings.
Rodent infestation in and around the home is the primary risk factor for HPS. It is hard to tell if a mouse or rat is infected with a hantavirus just by looking at it, so it is best to avoid all wild rodents and to safely clean up any rodent urine, droppings, or nests in your home.
The Person-to-Person Exception: Andes Virus
Most hantavirus strains cannot spread from one person to another. Only one hantavirus, the Andes strain native to South America, is known to have spread from person to person, and this is rare.
Andes virus (ANDV) is the unique hantavirus capable of being transmitted from person to person. Infection by this route takes place during the early prodromal phase (the early stage of illness before full symptoms develop), and the incubation period ranges from 9 to 40 days, according to research published in the journal Emerging Infectious Diseases.
A 2020 study published in the New England Journal of Medicine documented that from November 2018 through February 2019, person-to-person transmission of Andes virus in Chubut Province, Argentina, resulted in 34 confirmed infections and 11 deaths.
According to infectious disease researchers quoted by Gavi’s VaccinesWork, “hantaviruses are not transmissible from person to person except in extremely rare circumstances and only for one specific type of hantavirus called Andes virus, under very intensive close contact, for example, between sexual partners or from hospital patient to hospital staff.”
Given the ship came from South America, researchers noted it was plausible that the Andes strain may be responsible for the outbreak.
Symptoms: What to Watch For and When
The Early Phase – Easily Mistaken for Flu
As Dr. Sonja Bartolome of UT Southwestern Medical Center in Dallas explained, “Early in the illness, you really may not be able to tell the difference between hantavirus and having the flu.”
Symptoms of HPS usually start to show 1 to 8 weeks after contact with an infected rodent. Early symptoms include fatigue, fever, and muscle aches, especially in the large muscle groups like the thighs, hips, back, and sometimes shoulders. Additional early signs can include headaches, dizziness, chills, and abdominal problems.
Diagnosis in the first 72 hours of infection is difficult, the CDC has noted, and symptoms can easily be mistaken for the flu. This diagnostic window matters enormously, because what comes next can escalate with terrifying speed.
The Later Phase – Lung Failure
Four to 10 days after the initial phase of illness, the late symptoms of HPS appear. These symptoms include coughing and shortness of breath. Patients may experience tightness in the chest as the lungs fill with fluid.
As the virus damages the heart, lungs, or kidneys, patients can suffer severe shortness of breath, organ failure, and death.
Thirty-eight percent of people who develop respiratory symptoms may die from the disease, according to the CDC. This makes early recognition and hospital-level care the most critical factors in survival.
HFRS: The Kidney Syndrome
HFRS is a severe and sometimes deadly disease that affects the kidneys. Symptoms usually develop within 1 to 2 weeks after exposure. In rare cases, they may take up to 8 weeks to develop. Symptoms include intense headaches, back and stomach pain, fever, chills, nausea, blurred vision, and additional symptoms such as flushed face, inflamed or red eyes, rash, and low blood pressure, according to the Canadian Centre for Occupational Health and Safety.
How Hantavirus Is Diagnosed
Diagnosing hantavirus requires laboratory testing. Symptoms alone are not sufficient to distinguish it from influenza or other respiratory illnesses, particularly in the early stages.
Detection of hantavirus-specific antibodies remains the primary diagnostic criterion. The gold-standard diagnosis of hantavirus pulmonary syndrome is based on the detection of hantavirus-specific antibodies. Antibodies of the IgM class (immunoglobulin M, the first antibody your immune system produces during infection) are present during the earliest clinical stages. IgG antibodies against structural Sin Nombre virus proteins can often be detected even in the prodrome phase, according to research from Canada’s Public Health Agency.
If you have a fever, difficulty breathing, and have been exposed to rodents or rodent-contaminated materials, the California Department of Public Health recommends talking to a healthcare provider right away and telling them about recent exposure to rodents, especially mice.
If an individual has come into contact with rodents or rodent droppings and is experiencing symptoms, the National Collaborating Centre for Infectious Diseases advises contacting a healthcare provider and providing details about the contact, so rodent-specific diseases including hantavirus pulmonary syndrome can be explored.
The practical takeaway: if you have been cleaning a cabin, shed, barn, or any enclosed space that showed signs of rodent activity, and you then develop flu-like symptoms within 8 weeks, tell your doctor explicitly what you were doing before you got sick. This exposure history changes everything about how the case is assessed.
Treatment: There Is No Cure, But Timing Is Everything
There is no specific treatment for hantavirus infection. Patients should receive supportive care, including rest, hydration, and treatment of symptoms. HPS can cause breathing difficulties, and patients may need breathing support, such as intubation.
The typical course of treatment involves admission to intensive care, where a medical team tries to ease the patient’s symptoms, including by providing oxygen and placing them on a ventilator.
Hantavirus can be fatal, especially if it causes hantavirus pulmonary syndrome and is not caught early enough. At the same time, it is rare. Knowing the warning signs and acting quickly can make a big difference.
There are currently no approved vaccines for hantavirus anywhere in the world, and no antiviral medications have been licensed for treatment. Research into both continues, but for now, the only leverage available is prevention and early presentation to hospital.
Hantavirus in North America: Who Is Most at Risk
Over the last five years of reported data from 2020 to 2025, Arizona claimed the most confirmed US cases of hantavirus at 26, followed by New Mexico with 25 and Colorado with 13. CDC mapping shows that since 1993, New Mexico has recorded 122 cases, Colorado 119, and Arizona 86.
A vast majority, 94 percent, of all US hantavirus cases have come from west of the Mississippi River.
In Canada, since surveillance began in the early 1990s, 168 cases of hantavirus pulmonary syndrome have been confirmed by the National Microbiology Laboratory in Winnipeg, part of the Public Health Agency of Canada. That works out to an average of roughly five cases per year.
A breakdown of Canadian cases showed that more than half were found in Alberta (73 cases), followed by Saskatchewan (28), British Columbia (16), and Manitoba (5). Only one case of transmission to humans was reported east of the Prairie provinces, in Quebec.
The majority of cases in Canada occur in the spring and early summer. With the spring season underway, experts say Canadians should take precautions around rodents, particularly when reopening seasonal properties: “Especially at this time of the year in Canada, when you’re opening up seasonal buildings like cabins, cottages and sheds that haven’t been occupied over the winter.”
Read More: Mysterious Virus With No Known Treatment Spreads Quickly Along the West Coast
Prevention: How to Protect Yourself
Prevention comes down to one principle: reduce contact with rodents and their waste.
The best way to protect yourself from hantavirus, the CDC says, is to keep rodents out of your home by sealing any gaps or holes, keeping food well sealed, and putting garbage in thick containers with tight lids.
When you do find droppings, the cleaning method matters as much as anything else. Gather proper supplies including rubber or plastic gloves and a disinfectant or bleach solution. Air out the space for 30 minutes before cleaning. Spray the contaminated area with the disinfectant or bleach solution until very wet, and let it soak for at least 5 minutes.
Never sweep or vacuum dry rodent droppings. Avoid vacuuming or sweeping dried droppings, which can aerosolize the virus. Aerosolization, the process by which tiny particles become suspended in the air, is the most efficient route of infection.
The virus does not remain active for long once outside its host: less than one week outdoors and a few hours when exposed to direct sunlight, according to the Canadian Centre for Occupational Health and Safety. Proper ventilation and wet disinfection before any cleaning work take advantage of this vulnerability.
Dogs and cats cannot get sick from hantavirus infection or spread hantaviruses to people, according to the CDC.
What This Means for You
The MV Hondius outbreak is a jarring reminder that hantavirus, while rare, is not confined to rural settings or predictable circumstances. Three people lost their lives, and the international scientific community is still working to understand how the virus reached passengers aboard an ocean expedition vessel. The WHO currently assesses the risk to the global population from this event as low and will continue to monitor the epidemiological situation. But low risk is not zero risk, and that distinction has practical consequences.
Anyone who spends time in rural areas, cabins, barns, sheds, or anywhere rodents may be active should know the exposure risks and clean-up protocols. Experts warn that once symptoms appear, the disease can progress quickly. “The onset can be rapid, and death can occur within 24 to 36 hours,” making it critical to seek medical attention as fast as possible. If you develop flu-like symptoms within 8 weeks of potential rodent exposure, tell your doctor immediately and mention the contact explicitly. Early medical care can increase the chances of survival, even though there is no specific treatment or cure for HPS.
The MV Hondius investigation continues. Illness onset among those affected occurred between April 6 and April 28, 2026, and was characterized by fever, gastrointestinal symptoms, and rapid progression to pneumonia and acute respiratory distress. Given the long incubation period of hantavirus, it is possible that more cases could emerge in the coming weeks as researchers track all individuals who were aboard the vessel. Genome sequencing of the virus samples collected from patients will likely determine whether this was the Andes strain and, if so, whether person-to-person transmission played a role in what became one of the most unusual hantavirus events on record
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.
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