A total of seven suspected cases of hantavirus have been identified on a luxury cruise ship near Cape Verde, including three people who have died, with two cases confirmed.

The virus is usually spread from rodents, but the WHO said in this instance it could have spread among “really close contacts” aboard the MV Hondius vessel. It stressed the risk to the public was low.

The All Ireland SMC asked local experts to comment.


The All Ireland SMC asked local experts to comment on the research and implications for policy in Ireland and Northern Ireland.

Dr Gerald Barry,  Deputy Director of the University College Dublin One Health Centre, comments:

“While troubling, evidence points to a limited outbreak with low risk to the wider population. This ship originated in Argentina. In 2025 there were 229 cases and 59 deaths reported in South and Central America while in North America in 2024 there were 8 deaths associated with a Hantavirus infection. For context, Influenza virus infects millions of people and causes ten of thousands of deaths each year in South America, so infections and deaths associated with Hantaviruses are rare. Hantaviruses are a family of viruses that have a global distribution, carried mainly by rodents, including mice and rats here in Ireland. “

“Typically, spread is zoonotic, moving from rodents through their faeces and urine to humans with humans acting as dead-end hosts, which means that typically humans do not transmit the virus to other humans. The exception to this, is Orthohantavirus andesense, commonly known as Andes virus, which is a member of the Hantavirus family. According to the WHO there have been 5 reported outbreaks since 1996 (two in Argentina and three in Chile) where human to human transmission has been confirmed, all associated with Andes virus. Mortality rates with Hantaviruses vary, but with Andes virus it is approximately 40%, and higher in some cases. Although the type of Hantavirus hasn’t been confirmed in this cruise ship case, evidence points towards human to human transmission, suggesting it is Andes virus. Although human to human transmission can occur with this virus, it is not efficient, based on current evidence, so close contact for prolonged periods is needed. The first two cases were a couple, for example. “

“Incubation for these viruses can last from a week to a couple of months, so all passengers and staff on the boats will need to be tested for infection, symptoms alone can not be relied upon for presence of the virus and once confirmed uninfected, they should be allowed to disembark, with close follow up monitoring for 2-3 months by local public health officials. Those that are infected should be monitored and treated appropriately. There are some experimental treatments such as Ribavirin or convalescent plasma that may be effective in the very early stages of the infection and this could be considered but if the disease progresses, treatments to manage the symptoms are more appropriate.”

Declaration of interest: none received 

Dr Connor Bamford, Lecturer, School of Biological Sciences and The Institute for Global Food Security, Queen’s University Belfast, comments:

“The detection of hantavirus linked to an outbreak of fatal disease on a cruise ship is of great concern and reinforces the importance of zoonosis and ‘one health’ in medicine. However, this situation is nearly unprecedented and there are many questions about this that will need to be answered particularly around the source of infection and the extent of human-to-human spread. Although, it is unlikely this outbreak will spread beyond the ship. Hantaviruses are not usually human viruses but are primarily found in rodents across the world and can spread to people via contaminated urine or faeces. Although most infections in people are probably mild and can’t readily transmit between people (although it is possible), hantaviruses can cause severe fatal lung illnesses, particularly those strains found in South America where the cruise ship left. We currently lack any vaccines or antiviral medicines against these infections. During this investigation, the health and wellbeing of those on the ship must take priority while authorities uncover the source and potential for sustained transmission on the ship, which should facilitate a rapid and effective end to the potential outbreak. We may expect more cases to be uncovered before this ends.”

Declaration of interest: none received 

Dr Cliona O’Farrelly PhD Professor of Comparative Immunology, Trinity College Dublin, comments: 

“Hantaviruses can infect and cause serious disease in people worldwide. People get hantavirus infection from contact with rodents like rats and mice, especially when exposed to their urine, droppings, and saliva. It can also spread through a bite or scratch by a rodent – or by breathing in aerosolised skin or faeces from infected rodents, but this is thought to be rare. Currently, there is no approved vaccine nor a specific and effective antiviral treatment available for use in humans.

“It will be very interesting to get the genomics back on the purported hantavirus species that is thought to have caused the deaths and illness aboard the MV Hondius. Is it an Old World or New World strain? Might there be more than one?

“New World strains, such as Andes virus (ANDV) and Sin Nombre virus (SNV), are found in the Americas. They primarily cause hantavirus pulmonary syndrome (HPS). The most common hantavirus that causes HPS in the U.S. is spread by the deer mouse.

“Hemorrhagic fever with renal syndrome (HFRS) is caused by Old World hantaviruses. These are found mostly in Europe and Asia, such as Hantaan virus (HTNV), Dobrava and Puumala virus (PUUV). However, Seoul virus, a type of hantavirus that causes HFRS, is found worldwide.

“Hantaan and Dobrava virus infections usually cause severe symptoms; 5-15% of cases are fatal. In contrast, Seoul, Saaremaa, and Puumala virus infections are usually more moderate with less than 1% dying from the disease. Complete recovery can take several weeks to months.

“It would also be interesting to test all rodents on board. Is this a situation where the virus has evolved the ability to transmit from human to human? Or has a colony of rodents with high hantavirus levels manged to survive on the ship?

“Hantavirus outbreaks tend to happen when the animals that carry the virus become more numerous. Each type of hantavirus usually lives in a specific animal species, most often rodents, but sometimes insect-eating mammals like moles, shrews, or bats. Scientists think these viruses have evolved alongside their host animals over a long time. The animals carry the virus for life and have high levels of it in their blood, but they don’t get sick.”

Declaration of interest: None received 

Dr. Vikram Niranjan, PhD, Assistant Professor of Public Health, School of Medicine, University of Limerick

“Cruise ships might create ideal conditions for disease outbreaks due to their dense, enclosed environments—shared dining, ventilation systems and water infrastructure that facilitate rapid pathogen spread. The Diamond Princess (COVID-19, 2020) infected 619 of 3,711 people; norovirus repeatedly struck Celebrity Mercury (2010), Explorer of the Seas (2014) and Carnival Triumph (2013); Legionnaires’ disease has hit via contaminated hot tubs since 1994. These illnesses thrive because COVID exploits indoor air, norovirus loves buffets and surfaces, and Legionella might grow in ship plumbing—while older passengers face worse outcomes.

“HEPA filters, UV-C lights and fresh air exchange help, but sometime a maintenance gap may persist on older vessels. Travellers should prioritise handwashing, up-to-date vaccinations (flu/COVID), and check hygiene ratings pre-booking. Cruise operators could invest in robust air/water monitoring- Most cruise did good job in containment of outbreak as they have limited medical facility. As Irish ports like Cobh see rising cruise traffic, we need stronger public health oversight to protect both passengers and nearby communities from these predictable risks.”

Declaration of interest: I declare no conflict in interest.