Hantavirus explained: What we know after cruise ship deaths

A suspected hantavirus outbreak aboard a cruise ship has brought renewed attention to a rare but potentially deadly disease, after three people died and several others fell ill during a voyage spanning South America and Africa.

The vessel, currently off the coast of Cape Verde, has become the focus of an international response, with Dutch authorities working to repatriate affected passengers and health agencies racing to determine the cause of the illnesses. One confirmed case of hantavirus has been reported, while several others remain under investigation, leaving unanswered questions about whether the virus is directly linked to the deaths.

While hantavirus infections are uncommon, the situation has raised concern because of the confined environment of a cruise ship and the potential for exposure among passengers. Health officials, including the World Health Organisation (WHO), have said investigations, laboratory testing and virus sequencing are under way.

Here’s a closer look at hantavirus, how it spreads, and why the current outbreak is being closely watched.

What is hantavirus?

Hantavirus is not a single virus but a group of viruses carried primarily by rodents. In humans, it can cause serious illness affecting the lungs or kidneys, depending on the strain.

The virus has been known for decades, with cases reported in Asia and Europe, where it is often associated with haemorrhagic fever and kidney complications. A different form — hantavirus pulmonary syndrome — was identified in the United States in the early 1990s and is known for causing severe respiratory illness.

Though rare, the disease has drawn periodic global attention because of its high fatality rate in severe cases.

How does it spread?

Hantavirus is most commonly transmitted through contact with infected rodents or their bodily fluids, including urine, saliva and droppings.

In many cases, infection occurs when contaminated particles are disturbed and become airborne. People can then inhale these particles, particularly in enclosed or poorly ventilated spaces such as cabins, storage areas or sheds.

This mode of transmission makes activities such as cleaning rodent-infested spaces especially risky without proper precautions.

While the virus is primarily rodent-borne, health authorities note that human-to-human transmission, though rare, can occur in certain situations depending on the strain.

Key facts: Hantavirus

• What it is: A rare virus mainly spread by rodents

• Current trigger: Suspected cruise ship outbreak with 3 deaths

• Transmission: Rodent urine, droppings or saliva

• Airborne risk: Inhalation in enclosed spaces

• Human spread: Rare, but possible

• Symptoms: Flu-like early signs, severe breathing issues later

• Onset: 1 to 8 weeks after exposure

• Fatality rate: Around 35% (respiratory form)

• Treatment: No cure; early care is critical

• Prevention: Avoid rodents, disinfect carefully

What are the symptoms?

One of the challenges with hantavirus is that early symptoms can resemble common illnesses, making it difficult to detect in its initial stages.

Symptoms typically begin with:

• Fever and chills

• Muscle aches

• Headache

In many cases, patients may initially assume they have the flu.

However, the disease can progress rapidly. In cases of hantavirus pulmonary syndrome, patients may develop severe respiratory symptoms, including chest tightness and difficulty breathing as fluid accumulates in the lungs.

Another form of the disease affects the kidneys, leading to haemorrhagic fever with renal syndrome, which can cause internal bleeding and kidney failure.

Symptoms usually appear between one and eight weeks after exposure to the virus.

How dangerous is it?

The severity of hantavirus depends on the type of infection.

Hantavirus pulmonary syndrome, the form linked to respiratory complications, has a fatality rate of about 35 per cent. The kidney-related form has a lower mortality rate, typically ranging between 1 per cent and 15 per cent.

Medical experts stress that early diagnosis and hospital care can significantly improve outcomes. However, because symptoms can escalate quickly, delayed treatment increases the risk of severe complications.

Is there a cure or treatment?

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

Treatment focuses on supportive care, including oxygen therapy and close monitoring in hospital settings. In severe cases, patients may require intensive care to manage breathing difficulties and other complications.

Experts emphasise that early medical attention is critical, particularly once respiratory symptoms begin to develop.

Why is the cruise ship outbreak significant?

The current situation has drawn international attention for several reasons.

First, the outbreak involves multiple suspected cases and fatalities within a confined setting, raising concerns about exposure risks among passengers and crew.

Second, the exact cause of the deaths remains unclear. While one case of hantavirus has been confirmed, authorities have not yet established a direct link between the virus and all fatalities.

Third, the international nature of cruise travel adds complexity, requiring coordination between multiple countries for medical evacuation, testing and contact tracing.

The WHO has confirmed that further investigations, including laboratory analysis and epidemiological studies, are ongoing.

How can people protect themselves?

Public health experts say prevention is largely focused on reducing contact with rodents and contaminated environments.

Key precautions include:

• Avoiding areas where rodent droppings are present

• Using protective gloves and disinfectants when cleaning

• Ensuring good ventilation in enclosed spaces

• Avoiding sweeping or vacuuming contaminated areas, which can release particles into the air

Simple hygiene and awareness measures can significantly reduce the risk of exposure.

What happens next?

Health authorities are continuing to investigate the outbreak, with more clarity expected as testing and analysis progress.

For now, officials stress that hantavirus infections remain rare, and there is no indication of widespread risk to the general public.

However, the incident highlights how quickly infectious disease concerns can escalate in confined environments and underscores the importance of early detection, rapid response and international coordination in managing potential outbreaks.

- with inputs from AFP, AP