Hantavirus: are we at risk?
By: Dr. James Aw, Chief Medical Officer, OMERS
May 25, 2026
A recent infectious disease outbreak on a cruise ship departing from Ushuaia, Argentina on March 20, 2026 for an Antarctic expedition and Atlantic voyage has gained global attention. A tourist who was travelling on land for a few months in Argentina, Chile and Uruguay before boarding the cruise likely acquired hantavirus on a bird-watching trip and was exposed to infected rodent secretions. He boarded the ship on April 1, quickly developed severe respiratory symptoms and sadly died onboard on April 11. His wife developed gastrointestinal symptoms and disembarked the ship at Saint Helena and then flew to South Africa, where she unfortunately passed away on April 26.
Tragically, another tourist who was on the cruise ship died from pneumonia on May 2. Testing of these individuals confirmed the same hantavirus (named Andes virus) that is endemic in South America (mainly in Argentina and Chile, but cases have been found in Uruguay, southern Brazil and Paraguay). As of May 13, a total of 11 cases and three deaths have been reported, pointing to human-to-human transmission onboard the ship.
What is hantavirus?
Hantaviruses are a group of viruses that are carried by infected rodents. Humans can get infected if they are in contact with rodent secretions (urine, droppings and/or saliva). It was first identified during the Korean war in the 1950s and named after the Hantan river which runs south of the demilitarized zone. Past outbreaks have been documented in 1993 in the American “Four Corner” states around the Mississippi River and in 2018-2019 in Epuyen, Argentina. The highest risk occurs when living (recreational cabins/cottages) or working (agricultural workers, construction and demolition, pest control, military, etc.) within rodent-contaminated areas. Most cases in Canada are in the west and involve deer mice. The virus exists in the Americas, Asia and Europe, but the type and severity of human disease is different based on geography. Each hantavirus (over 20 subtypes) is associated with a specific rodent species who may be carriers. There are two main types of human illness. In the Americas, the virus can cause hantavirus cardiopulmonary syndrome (severe heart and lung disease) with a high fatality rate of 40-50%. In Europe and Asia, hantaviruses cause disease in the kidneys (hemorrhagic renal syndrome) with a lower fatality rate of <1-15%. Globally, there are approximately 10,000 to over 100,000 infections annually. In 2025, eight countries in the Americas reported just over 200 cases. It is more common in Europe (northern and central) and Asia (China, Republic of Korea), with several thousand cases annually. There is no treatment or vaccine for hantavirus, but ribavirin may improve outcomes for hantavirus hemorrhagic fever with kidney disease (though not for hantavirus lung disease).
Human-to-human transmission has only been reported with the Andes virus from South America. Other hantavirus species infect humans directly from close contact with rodent secretions.
Is there anything particularly concerning about this ship outbreak?
Cruise ships have been known for outbreaks from respiratory and/or stomach viruses like norovirus, influenza and COVID-19. However, this is the first incidence of human-to-human transmission of hantavirus on a cruise ship, and the fatality rate is high with the Andes strain. Another challenge in this case is the prolonged incubation period. Hantavirus has a long incubation period of 4-6 weeks, so more cases in passengers may be popping up since the last reported case from the ship. The cruise ship had 149 passengers from 23 countries, and the average age is 65 years old. The global public health community and World Health Organization are coordinating contact tracing and quarantining protocols (45 days post-exposure) for those exposed to the ship virus.
What am I watching out for?
If new cases keep popping up globally in the summer (particularly if they don’t have a direct link to passengers), then there may be a concern about sustained human-to-human transmission. Another concern is whether severe (or unusual) hantavirus clinical symptoms start developing in healthy individuals (i.e. children, young adults). The infected cases during this outbreak involve seniors.
Climate change, geopolitical instability and increasing human proximity and prolonged contact with rodent habitats may influence disease trends (rodent populations, rising cases).
Human cases of hantavirus in Argentina are rising in the past year, and this may be linked to climate change. If more cases of Andes virus start showing up in humans and rodents outside of South America, then that might indicate an emerging global risk in new territories for potential human-to-human transmission.
Should we be worried?
No. The highest risk is for passengers on the original cruise ship, and they are being monitored during the completion of the viral incubation period from the ship outbreak. This is not a new virus, and it is relatively rare. Historically, it has not been known to be easily transmitted between humans and people are most contagious during the early phase of the illness. High-risk contacts include intimate partners, household contacts and people with prolonged close indoor exposure, healthcare workers without personal protective equipment and people handling contaminated materials.
We will all be watching the story closely and hopefully the outbreak will end quickly.
For those who want to read more!
World Health Organization: https://www.who.int/news-room/fact-sheets/detail/hantavirus
Public Health Canada: https://www.publichealthontario.ca/en/Diseases-and-Conditions/Infectious-Diseases/Vector-Borne-Zoonotic-Diseases/Hantavirus
Europe Centre for Disease Control and Prevention: https://www.ecdc.europa.eu/en/hantavirus-infection
Communicable Diseases Agency Singapore: https://www.cda.gov.sg/
The information, content and material provided by OMERS Administration Corporation at each link on this page is provided for informational purposes only and is not intended to be, or to substitute for, medical advice. Always seek the advice of a qualified healthcare professional if you have any questions regarding a medical condition or treatment and do not disregard or delay seeking professional medical advice because of the content provided at any of the links on this page. OMERS AC and its affiliates and other investment entities are not responsible or liable in any manner for your use of or reliance on the above information.
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