What is hantavirus and why is it in the news?

Hantavirus. Credit: Getty/quantic69

By Emma Wilkinson

As the World Health Organization confirms three people have died after a suspected hantavirus outbreak on a cruise ship, Doctors.net.uk looks at what is known so far.

What has happened on the cruise ship?

A cluster of passengers with severe respiratory illness onboard a cruise ship was reported to the World Health Organization (WHO) on 2 May. The first case on the MV Hondius was in early April.

The Dutch cruise ship, which had been travelling to remote areas in the South Atlantic, set off in March from Argentina with 147 passengers.

It has visited a number of remote and “ecologically diverse” regions, including Antarctica, South Georgia, Nightingale Island, Saint Helena and Ascension Island and is now moored near Cabo Verde, off the coast of west Africa.

Eight cases have been reported so far, including three deaths. Five of the eight cases have been confirmed as hantavirus. Three British nationals have been diagnosed with suspected disease. A 69-year-old British national who is being treated in intensive care in a hospital in South Africa has also been confirmed to have hantavirus.

A 69-year old British national is being treated in intensive care in South Africa and the latest suspected case is in a British national on Tristan da Cunha.

What is hantavirus and how common is it?

Hantaviruses are a group of viruses carried by rodents that can cause two serious infections in humans: hantavirus pulmonary syndrome (HPS) and haemorrhagic fever with renal syndrome (HFRS).

HPS is a zoonotic, viral respiratory disease with more than 20 viral species identified. Infection is acquired through contact with the urine, faeces, or saliva of infected rodents.

It is a rare but severe disease that can be deadly. In 2025, eight countries in the Americas reported 229 cases and 59 deaths, the WHO reports.

Symptoms can progress rapidly to cough, shortness of breath, pulmonary oedema and shock, although these may be difficult to pick up initially due to similarity with other febrile and respiratory illnesses.

Hantaviruses in Europe, Asia and Africa tend to cause HFRS, although cases in the UK are very rare. In East Asia, particularly China and the Republic of Korea, there are many thousands of cases of HFRS every year, but incidence appears to be declining.

Although uncommon, limited human-to-human transmission has been reported in previous outbreaks of a specific species of hantavirus known as Andes virus. The WHO also states that in rare cases secondary infections among healthcare workers have been documented in healthcare facilities.

There may have been person-to-person transmission in this case, the WHO has said.

The first two cases – a husband and wife - had travelled in South America, including Argentina, before they boarded the cruise ship.

Dr Maria Van Kerkhove, from the WHO, said it was likely they were infected before boarding.

“However, we do believe that there may be some human-to-human transmission that’s happening among the really close contacts – the husband and wife, people who have shared cabins, etc.

“So again, our assumption is that has happened, and that’s why we are operating and working with the ship to make sure that anyone who is symptomatic, anyone caring for patients, is wearing full personal protective equipment.

“The medical personnel who have boarded the boat have brought additional PPE as well."

The WHO notes that exposure is usually through activities such as cleaning buildings with rodent infestations, though it can also be linked to routine activities for people in heavily infested areas.

Human cases are most commonly reported in rural settings, including farms, where there is more opportunity for exposure.

The extent of passenger contact with local wildlife during the voyage, or prior to boarding “remains undetermined”, the WHO says.

Symptoms of HPS typically occur around two to four weeks after initial exposure to the virus but can appear as early as one week and as late as eight weeks. 

What treatment or prevention is available?

Hantavirus infections are associated with a case fatality rate of between 1 to 15% in Asia and Europe and up to 50% in the Americas.

There is no specific antiviral treatment for HPS and neither is there a vaccine available. Suspected cases are treated with early supportive care and immediate referral to a facility with intensive care to improve the chance of survival. 

For those on board the ship, early recognition of suspected cases, prompt isolation, and consistent adherence to infection prevention and control measures remain essential, WHO has said.

Suspected cases need to be transferred quickly to an emergency department or intensive care for close monitoring.

Clinicians can offer fluids, haemodynamic monitoring, and respiratory support with mechanical ventilation or even extracorporeal mechanical oxygenation if needed.

What has been the public health response?

The WHO said the outbreak is being managed through coordinated international response, and includes in-depth investigations, case isolation and care, medical evacuation and laboratory investigations. UK officials have been involved in the response.

Prime Minister Sir Keir Starmer said the government is putting “plans in place” for the safe onward travel of Britons stuck aboard the cruise ship.

“The risk to the wider public remains very low – protecting the British people is our number one priority,” Starmer said.

As yet the source of the hantavirus exposure has not been identified and passengers on the cruise ship have been advised to practice maximal physical distancing and remain in their cabins where possible.

In terms of risk to the global population from this event, it has been rated as low, but it will continue to be assessed. 

Updated on 06 April at 08:42am with additional information.

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