This blog post was last updated on Tuesday 12 May 2026.
You can find the latest on the ongoing outbreak of hantavirus on our dedicated blog post.
What is hantavirus?
Hantaviruses are a group of viruses carried by rodents such as mice and rats, transmitted by their droppings and urine. Hantaviruses are present throughout the world. They can be found in some areas of Europe, Africa, Asia and South America. Where they are present, they can cause a range of diseases from mild, flu-like illness to severe respiratory illness.
How common are hantaviruses?
Hantavirus infections are relatively rare globally but are more common in some regions. In Europe, just under 1,900 cases were recorded in 2023 across all different strains of hantavirus. In the Americas, 8 countries reported 229 cases in 2025. East Asia sees the highest burden, with many thousands of cases annually in China and South Korea, although case numbers have declined in recent decades. Andes hantavirus infection is very rare, and while it can spread between people, this only happens with very close contact and most cases are still caused by exposure to infected rodents.
Where does the name ‘hantavirus’ come from?
The name hantavirus comes from the Hantan River. In the late 1970s, scientists identified a virus in field mice living near the river while investigating cases of a serious illness known at the time as Korean haemorrhagic fever. The virus was named Hantaan virus after the river. As more related viruses were discovered around the world, they were grouped together and given the collective name hantaviruses.
How do you catch hantavirus?
As hantaviruses are carried by rodents, infections in humans tend to occur in places where people and rodents coexist. This is most commonly in rural, agricultural settings. The viruses can also sometimes be found in cleaning sheds, barns and holiday homes where rodents might have nested. In the UK we occasionally see cases of one strain of hantavirus (Seoul hantavirus) associated with pet rats. This strain has not been shown to transmit between humans.
How do hantaviruses spread?
Most hantaviruses do not spread between humans, although person-to-person transmission has happened with the Andes virus strain in rare cases. Andes hantavirus is the strain of hantavirus identified in the 2026 cruise ship outbreak. People usually become infected by breathing in air contaminated with virus particles from rodent urine, droppings, or saliva. The virus can also enter the body through cuts, the eyes or very rarely, a rodent bite. For the Andes virus strain, where there is evidence of person-to-person transmission, it spreads through very close contact.
How contagious is hantavirus?
Hantavirus is not spread through everyday social contact like walking in public spaces, shops, workplaces, or schools. In the rare instances where a person has caught the infection from another person (rather than from a rodent), they have had close and prolonged contact with the person who has been infected with hantavirus. This would include people who share living spaces.
What are the symptoms?
Symptoms of hantavirus infection can include fever, extreme fatigue, muscle aches, stomach pain, nausea, vomiting, diarrhoea, or shortness of breath. In some cases, people develop severe breathing difficulties requiring hospital care. Symptoms usually appear between 2 to 4 weeks after being exposed to the virus, but there are reports of symptoms occurring up to 40 days after exposure.
How is the virus treated?
There is currently no vaccine or specific antiviral treatment for most hantavirus infections. Treatment is supportive and based on symptoms, such as hospital care and respiratory support.
What is the mortality rate?
The mortality rate of hantaviruses varies considerably depending on the strain and the quality of care available. For the Andes virus, it has been estimated at up to 30 to 50%, however the upper end of that estimate is from data published about 30 years ago and has since declined. With prompt hospital treatment and respiratory support, outcomes may be significantly better.
Do UK rodents carry hantavirus?
Yes, though not the strains most commonly associated with serious outbreaks elsewhere in the world. The Andes virus - responsible for many cases in South America - has never been detected in the UK rodent population.
The strain we see in the UK is Seoul hantavirus, which is carried by both wild brown rats and pet rats. Occasional cases are seen here, caught from rodents, but Seoul hantavirus does not spread between people.
Read the UKHSA guidance on reducing the risk of infection from pet rodents.
What is UKHSA’s responsibility around cases of hantavirus?
We are the government agency responsible for protecting people in the UK from the impact of infectious diseases, among other health threats. We provide scientific expertise and operational capacity that is needed during outbreaks and develop guidance for local authorities, the NHS and the public.
How high is the risk of hantavirus in the UK?
The risk to the public in the UK is very low. The only strain ever identified here is Seoul hantavirus, which does not spread between people. Follow government guidance if you keep pet rodents, to reduce the risk of catching infections including Seoul hantavirus.