Suspected hantavirus outbreak on cruise ship as WHO launched probe

Health officials say one case has been confirmed in a British passenger, who is now in intensive care, with several more cases under investigation.

The cruise ship outbreak

The World Health Organisation (WHO) is investigating a suspected hantavirus outbreak on board the MV Hondius, a Dutch‑flagged cruise ship that had been sailing from Argentina to Cape Verde.

Three people have died, and at least three others have become seriously unwell after developing sudden, severe symptoms during the voyage

The first person to fall ill was a 70‑year‑old man who “suddenly became ill” on board and died after the ship reached St Helena Island.

His 69‑year‑old wife later became unwell and died in a South African hospital, while a British passenger has tested positive for hantavirus and is being treated in intensive care.

The WHO says detailed investigations are underway, including further laboratory testing and genetic sequencing of the virus, while medical care is being provided to passengers and crew.

Officials are also coordinating with national authorities and the ship’s operators to arrange medical evacuation for symptomatic passengers and assess the wider public health risk.

The outbreak started on a cruise ship (Image: Unsplash)

What exactly is hantavirus?

Hantavirus is not a single virus but a family of viruses carried mainly by rodents.

When transmitted to humans, these viruses can cause serious, sometimes fatal illness, most commonly affecting the lungs or kidneys.

There are two main disease patterns linked to hantavirus:

• Hantavirus pulmonary syndrome (HPS), sometimes called hantavirus cardiopulmonary syndrome, is more common in the Americas and causes severe respiratory illness.
• Haemorrhagic fever with renal syndrome (HFRS), seen more often in Europe and Asia, which affects the kidneys and can cause internal bleeding and organ failure.

Different strains are associated with different rodent hosts and regions.

How hantavirus spreads

In most cases, people catch hantavirus through contact with infected rodents or environments contaminated by them.

The virus is shed in rodent urine, faeces and saliva, and can become airborne when dried droppings or nesting material are disturbed.

People typically become infected by:

• Breathing in tiny particles from contaminated dust or droppings.
• Getting contaminated material into small cuts in the skin.
• Eating food that has been contaminated.
• More rarely, being bitten or scratched by an infected rodent.

Human‑to‑human transmission is generally considered rare, but it has been documented with some strains.

In the cruise ship incident, investigators have not yet identified the source of infection, and person‑to‑person spread has not been ruled out.

The disease is spread through rodents (Image: Rats)

Who is most at risk?

The risk of hantavirus is closely linked to rodent exposure.

People are more likely to be infected if they:

• Clean or enter spaces where rodents live or have nested, such as cabins, sheds, barns or outbuildings.
• Work in jobs that bring them into contact with rodents or their droppings, such as pest control, farming, forestry or some construction work.
• Camp, hike or spend extended time in wilderness areas with high rodent populations.
• Handle rodents, whether in the wild or as pets.

However, as the cruise ship outbreak suggests, infection can occur in less obvious settings if rodents have had access to stored food, cargo, or parts of a vessel or building.

Symptoms to look out for

Hantavirus infections often start like a bad flu, which can make early diagnosis difficult.

Symptoms usually appear between one and eight weeks after exposure.

Early signs can include:

• Fever and chills.
• Severe muscle aches, especially in the back, hips, thighs and shoulders.
• Extreme tiredness and weakness.
• Headache and dizziness.
• Nausea, vomiting, diarrhoea and stomach pain.
• Occasionally, a rash.

After several days, some patients rapidly worsen.
In hantavirus pulmonary syndrome, the lungs begin to fill with fluid, leading to:

• A dry cough that quickly progresses to severe difficulty breathing.
• Chest tightness and a feeling of suffocation.
• Low blood pressure and a fast or irregular heartbeat.
• In the worst cases, shock and multiple organ failure.

In haemorrhagic fever with renal syndrome, the focus is more on:

• High fever and intense headache.
• Abdominal and back pain.
• Bleeding under the skin or from the nose and gums.
• Kidney problems, which can progress to acute kidney failure.

The sudden shift from “flu‑like” to life‑threatening symptoms is one of the hallmarks of severe hantavirus disease.

Patients can appear relatively stable and then deteriorate over the course of hours.

How doctors diagnose and treat it

Because early symptoms resemble many other viral illnesses, doctors rely on blood tests to confirm hantavirus infection.

These tests look for genetic material from the virus or antibodies produced by the patient’s immune system.

There is currently no widely available specific cure or vaccine for hantavirus.

Treatment focuses on intensive supportive care, which may include:

• Oxygen therapy or mechanical ventilation to support the lungs.
• Medicines and fluids to stabilise blood pressure and heart function.
• Dialysis or other support if the kidneys fail.
• In the most severe cases, advanced life‑support techniques such as ECMO, where a machine temporarily takes over the work of the heart and lungs.

An antiviral drug called ribavirin has shown some benefit in certain forms of hantavirus disease when given early, but it is not a guaranteed treatment and is used selectively.

Recovery can be slow even for survivors, with lingering fatigue and reduced exercise tolerance.

How people can reduce their risk

Public health advice around hantavirus centres on avoiding contact with rodents and their droppings.
Experts recommend:

• Sealing up holes and gaps that could allow rodents into homes, cabins, food stores or ships.
• Trapping and removing rodents safely where infestations are found.
• Using disinfectant and damp cleaning methods rather than sweeping or vacuuming dry droppings, to avoid creating dust.
• Wearing gloves and, in higher‑risk settings, masks when cleaning areas that may be contaminated.

On ships and in other shared environments, robust pest control, careful food storage and regular inspections are key.

Officials investigating the MV Hondius outbreak are now trying to understand exactly where and how passengers were exposed.