A rare virus carried by rodents has infected 13 people and killed three during an outbreak linked to an Antarctic cruise ship, which has triggered a global public health response led by the World Health Organisation (WHO).

The outbreak involves Andes virus, a type of hantavirus that is mainly found in South America. According to the WHO, all 13 cases were passengers or crew members aboard the cruise ship MV Hondius. Eleven cases have been laboratory confirmed, while two are considered probable cases.

The outbreak was first reported in early May after several passengers developed severe respiratory illness. Cases have since been identified among passengers and crew linked to the cruise ship, with confirmed infections reported in Canada, the Netherlands, and Spain. The investigation has also involved the United Kingdom, the United States, Cabo Verde, Argentina, and Chile, while health authorities are monitoring more than 600 contacts across 32 countries, territories, and areas.

Passengers and crew left the ship at Saint Helena and Ascension Island, both British Overseas Territories, as well as Praia in Cabo Verde and Tenerife in Spain. Health authorities in several countries have been working together to trace contacts and monitor people who may have been exposed during the voyage or later travel.

What is hantavirus?

Hantaviruses are a group of viruses carried by rodents. People usually become infected through contact with infected rodents or by inhaling particles from their urine, droppings, or saliva.

Different hantaviruses can cause different illnesses. In North and South America, infection can lead to Hantavirus Pulmonary Syndrome (HPS), a serious disease that affects the lungs and can cause death.

WHO said HPS can have a death rate of between 40 and 50 per cent, particularly among older people and those with existing health conditions.

How does it spread?

Most hantavirus infections are caused by contact with infected rodents or contaminated environments. However, the Andes virus is unusual because it is the only hantavirus known to spread between people.

WHO said that human-to-human transmission is rare and usually requires close contact. Previous outbreaks have mainly involved family members or people sharing indoor spaces for long periods.

Experts are still studying how the virus spread on the cruise ship. WHO said it may spread through close contact, contaminated surfaces, or respiratory particles, but more research is needed.

Importantly, WHO said the virus does not spread as easily as measles.

What are the symptoms?

Symptoms start with fever, headache, muscle aches, tiredness, and stomach problems.

In severe cases, patients can develop breathing difficulties as fluid builds up in the lungs, requiring intensive care. There is currently no approved antiviral treatment for HPS.

What does this mean for Samoa?

While no cases have been confirmed in Samoa so far, the Ministry of Health has been contacted via email for comment and has not yet responded. 

However, the outbreak highlights how infectious diseases can quickly become an international concern through modern travel. 

The cruise ship carried passengers and crew from multiple countries, and health authorities across several continents have been involved in tracing contacts and monitoring potential exposures. 

WHO said the overall risk to the general public remains low.

How can people protect themselves?

WHO recommends reducing exposure to rodents and areas where they may be present. Prevention measures include keeping homes, workplaces, and storage areas clean; sealing gaps where rodents can enter; safely cleaning areas contaminated by rodent droppings or urine; avoiding contact with rodents, whether alive or dead; and washing hands regularly with soap and water. People who develop symptoms after possible exposure should seek medical care.

For those who had close contact with confirmed Andes virus cases, WHO advises monitoring for symptoms and following public health guidance. WHO does not recommend any travel or trade restrictions for the general public. Health authorities continue to monitor the situation while scientists investigate how the virus spread aboard the M/V Hondius.