What Is Hantavirus? The MV Hondius Outbreak Explained

On Sunday 4 May 2026, the World Health Organization confirmed a suspected hantavirus outbreak on board the MV Hondius — a Dutch-flagged expedition cruise ship currently anchored off Praia, the capital of Cape Verde. Three passengers have died. A British tourist is in intensive care in Johannesburg, South Africa, with a laboratory-confirmed hantavirus infection. Two crew members on board require urgent medical care.

The outbreak has attracted international attention partly because of its setting — hantavirus outbreaks on cruise ships are extraordinarily rare — and partly because of the possibility, not yet confirmed, that the Andes variant of hantavirus may be involved, which is the only known form capable of spreading from person to person.

Here is what is known, what remains uncertain, and what the science of hantavirus actually shows.

TL;DR

• Hantaviruses are a family of viruses normally transmitted to humans through exposure to the urine, saliva, or faeces of infected rodents. They are not typically transmitted person to person — with one known exception.
• Three passengers on the MV Hondius have died. One case has been laboratory confirmed as hantavirus. Five other cases are suspected. A British tourist is in intensive care in South Africa.
• The ship left Ushuaia, Argentina approximately seven weeks ago — a region where the Andes virus, the only hantavirus known to spread person to person, is endemic.
• Hantavirus pulmonary syndrome — the severe respiratory form — has a mortality rate of over 30% in patients who develop respiratory symptoms.
• There is no specific antiviral treatment for hantavirus. Management is supportive — oxygen, fluid management, and in severe cases mechanical ventilation.
• The risk to the general public from this outbreak is very low. Hantavirus does not spread easily between people and requires direct contact with rodent excreta or, in the Andes variant case, very close contact with an infected person.

What Is Hantavirus?

Hantaviruses are a family of RNA viruses found worldwide, carried by various rodent species — primarily mice and rats — that shed the virus in their urine, droppings, and saliva without becoming ill themselves.

Human infection occurs primarily through inhalation of aerosolised particles from infected rodent excreta. In rural settings this typically happens when disturbing rodent nesting sites — sweeping a barn, opening a long-closed cabin, clearing brush. It can also occur through direct contact with infected material via broken skin, or less commonly through a rodent bite.

The virus does not spread easily between people. One family physician and infectious disease specialist who commented to CNN on the MV Hondius outbreak noted that when he first read the report he thought it was a misprint — hantavirus outbreaks on ships are not something infectious disease medicine is prepared for.

Two primary clinical syndromes are associated with hantavirus infection:

Hantavirus Pulmonary Syndrome (HPS) — the form most prevalent in the Americas, including the Andes and Sin Nombre viruses. Initial symptoms resemble influenza — fatigue, fever, muscle aches, headache, dizziness, and sometimes nausea, vomiting, and abdominal pain. These early symptoms typically last three to five days before the disease either resolves or progresses to the respiratory phase, in which the lungs fill with fluid. More than one third of patients who experience respiratory symptoms may die from the syndrome.

Haemorrhagic Fever with Renal Syndrome (HFRS) — the form most prevalent in Europe and Asia, caused by Hantaan, Seoul, Puumala, and Dobrava viruses. Produces kidney disease rather than the severe respiratory syndrome, with symptoms including fever, headache, back and abdominal pain, and in severe cases kidney failure and haemorrhage. Generally lower mortality than HPS.

Why This Outbreak Is Medically Unusual

Infectious disease specialists have described the MV Hondius outbreak as highly unusual for several reasons — and the uncertainty around how it occurred is clinically significant.

The ship left Ushuaia in Argentina approximately seven weeks ago and made stops in Antarctica and the British overseas territory of Saint Helena before anchoring off Cape Verde. It carries 170 passengers and 71 crew.

There are two plausible ways that the suspected outbreak could have occurred. One, the ship could have become contaminated with rat or mice faeces or urine. Two, one of the passengers could have picked up the Andes variant of hantavirus, for which there is some limited evidence of human-to-human transmission.

The Andes virus — endemic to Chile and Argentina, where the ship originated — is the only hantavirus known to spread between people. Person-to-person transmission has been documented in small clusters in South America, primarily through very close contact. If the MV Hondius outbreak is confirmed as Andes virus with person-to-person spread, it will "change the future of travel medicine and infectious disease and tropical medicine," according to Scott Miscovich, a family physician and infectious disease specialist who spoke to CNN.

The WHO has noted that while rare, hantavirus may spread between people and requires careful patient monitoring, support, and response. Investigations are ongoing.

The Victims

Two of the people who died were identified as a married couple — a 70-year-old man declared dead on arrival in St. Helena, and a 69-year-old woman who collapsed at Johannesburg's international airport while attempting to fly to the pair's home country of the Netherlands and died at a health facility.

A third passenger has also died. A passenger from the UK who became ill while the cruise ship was travelling from St. Helena to Ascension Island was being treated at a hospital in South Africa. His lab results tested positive for hantavirus. He is not among the dead — as of the most recent reports he remains in intensive care.

Symptoms to Know

Hantavirus infection progresses through two distinct phases and the early phase is easily confused with influenza or other common viral illnesses — which is part of what makes it dangerous.

Early phase (days 1 to 5):

• Fatigue and exhaustion
• Fever — typically above 38°C
• Muscle aches — particularly in the large muscle groups of the thighs, hips, and back
• Headache
• Dizziness
• Chills
• Nausea, vomiting, diarrhoea, and abdominal pain in some patients

Cardiopulmonary phase (days 4 to 10 in HPS):

• Coughing
• Shortness of breath
• Tightness in the chest
• Rapid deterioration as the lungs fill with fluid
• In severe cases — respiratory failure requiring mechanical ventilation

The transition from early phase to cardiopulmonary phase can be rapid and is the point at which the condition becomes life-threatening. Anyone who has been in an area where hantavirus is endemic — including Patagonia, Argentina, Chile, and parts of the American Southwest — and develops influenza-like symptoms with progressive breathing difficulties should seek urgent medical assessment and disclose their travel history. Lingering or atypical respiratory symptoms after travel can be easy to dismiss in a season already crowded with viral illness — something we covered when looking at why hay fever symptoms are lasting longer than people expect.

Treatment and Prognosis

There is no specific antiviral treatment for hantavirus. No vaccine exists. Management is entirely supportive — oxygen supplementation, fluid management, and in severe cases mechanical ventilation in an intensive care setting.

Early recognition and hospitalisation significantly improve outcomes. Patients who are intubated and receive intensive supportive care have better survival rates than those who present late or in very remote settings where intensive care is unavailable.

The mortality rate for hantavirus pulmonary syndrome in patients who develop the respiratory phase exceeds 30%. For the milder haemorrhagic fever with renal syndrome forms prevalent in Europe, mortality is lower — typically below 5% with good medical care. The CDC's hantavirus resources give a fuller clinical breakdown for clinicians and travellers.

What the Risk Is for the General Public

The risk to the general public from the MV Hondius outbreak is very low — and it is important to be clear about this.

Hantavirus does not spread casually. It is not transmitted through coughing, sneezing, or ordinary social contact in the way that influenza or COVID-19 spread. The typical transmission route requires direct exposure to infected rodent excreta — a situation that does not arise in everyday urban or suburban life in the UK.

The Andes variant — the only form with known person-to-person transmission — is found in Chile and Argentina, not in Europe, and the person-to-person transmission that has been documented requires very close, prolonged contact with an infected individual.

For people currently on cruise ships or planning cruise travel: hantavirus outbreaks on ships are extraordinarily rare — this is the first confirmed outbreak of this scale on a cruise vessel. Standard hygiene measures, including avoiding contact with any rodents or rodent signs on a vessel, are appropriate precautions.

For people who have recently travelled to Patagonia, Argentina, or Chile and develop influenza-like symptoms: disclose your travel history to a GP immediately. Early recognition is the most important factor in outcome. Bodily symptoms after a stressful or unusual trip are also easier to second-guess than they should be — something we explored when writing about the hidden physical effects of grief and how easily real physical signals get rationalised away.

The Gene Hackman Connection

Hantavirus attracted significant public attention in February 2025 following the deaths of Gene Hackman and his wife Betsy Arakawa at their home in New Mexico. Betsy Arakawa died of hantavirus pulmonary syndrome. Hackman, 95 and in poor health, died from heart disease and Alzheimer's disease, likely about a week after his wife.

The New Mexico case was consistent with the most common transmission route — exposure to infected rodent excreta in a rural property. The Hondius outbreak is a very different clinical picture — multiple cases in a contained ship environment — which is why it is attracting such significant medical attention.

Frequently Asked Questions

What is hantavirus?

Hantavirus is a family of RNA viruses carried by rodents — primarily mice and rats — that can infect humans through exposure to infected rodent urine, droppings, or saliva. In the Americas, hantavirus typically causes hantavirus pulmonary syndrome — a severe respiratory illness with a mortality rate exceeding 30% in patients who develop breathing difficulties. In Europe and Asia, hantavirus more commonly causes haemorrhagic fever with renal syndrome, which affects the kidneys. There is no specific antiviral treatment and no vaccine.

How does hantavirus spread?

Hantavirus is primarily transmitted through inhalation of aerosolised particles from infected rodent excreta — dried urine, droppings, or nesting material disturbed into the air. It can also enter through broken skin or rodent bites. It does not typically spread between people — with one known exception. The Andes virus, found in Chile and Argentina, has documented limited person-to-person transmission through very close contact, making the MV Hondius outbreak — which originated in Argentina — of particular interest to investigators.

What are the symptoms of hantavirus?

Early symptoms — typically appearing one to five weeks after exposure — include fatigue, fever, severe muscle aches, headache, dizziness, and chills. Some patients also experience nausea, vomiting, and abdominal pain. In hantavirus pulmonary syndrome, these early symptoms are followed by rapid respiratory deterioration — coughing, shortness of breath, and chest tightness as the lungs fill with fluid. The transition from early to respiratory phase can occur quickly and is the most dangerous period.

Is there a cure for hantavirus?

No. There is no specific antiviral treatment and no vaccine for hantavirus. Management is supportive — oxygen, fluid management, and mechanical ventilation in severe cases. Early recognition and access to intensive care significantly improve survival. This is why early medical assessment for anyone with potential exposure and influenza-like symptoms is critical.

Should I be worried about hantavirus in the UK?

The risk to people in the UK is very low. Hantavirus does not spread casually between people, requires direct exposure to infected rodent excreta, and the Andes variant with person-to-person transmission is endemic to South America, not Europe. People who have recently travelled to Patagonia, Argentina, or Chile and develop influenza-like symptoms should disclose their travel history to a GP immediately, as early recognition significantly improves outcomes.

What is happening on the MV Hondius?

The MV Hondius is a Dutch-flagged expedition cruise ship currently anchored off Praia, Cape Verde, following a suspected hantavirus outbreak. Three passengers have died. One case has been laboratory confirmed as hantavirus, with five further suspected cases. A British tourist with a confirmed positive test is in intensive care in South Africa. The WHO is coordinating the response and has notified global health authorities. Cape Verdean authorities have assessed the ship but as of Sunday evening had not authorised passenger disembarkation. Investigations into the source and transmission route are ongoing.

The Bottom Line

The MV Hondius outbreak is a rare and medically significant event — not because hantavirus itself is new or widespread, but because its appearance in a cruise ship context, with multiple cases, raises questions about transmission routes that standard hantavirus epidemiology does not easily explain.

The investigation will focus on whether rodent contamination on the vessel is the source, or whether the Andes variant with its limited person-to-person transmission capacity is involved. The answer matters significantly for how travel medicine approaches future expedition cruises through endemic regions.

For the general public, the risk is low. For anyone with recent travel to South America who develops fever, muscle aches, and respiratory symptoms — early medical assessment and disclosure of travel history is the single most important action.

If you find yourself wading through travel-medicine questions, symptom-tracking, or just trying to make sense of conflicting health headlines, our Reset Companion is built for exactly that — a calm, evidence-led second opinion you can actually talk to.

We will update this article as the investigation progresses.

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