How people get infected
Hantaviruses live in rodents — mice, rats and voles — without making them sick. Humans stumble into the cycle by breathing in dust contaminated with rodent urine, droppings or saliva, typically when cleaning a shed, opening a long-closed cabin, or disturbing nesting material. The virus doesn't survive long in the open; sunlight and disinfectant kill it within hours. But in dark, enclosed spaces where droppings accumulate undisturbed, infectious particles can linger for days.
A bite from an infected rodent can also transmit the virus, though this is uncommon. Food or water contaminated with rodent excreta is another theoretical route, but documented cases are rare.
Two diseases, two continents
Hantavirus Pulmonary Syndrome (HPS)
Where: Americas — North, Central, South
What it does: Attacks the lungs. Fluid floods the alveoli, triggering acute respiratory distress syndrome. Blood pressure drops, organs fail.
Fatality: Up to 50% without intensive care
Key viruses: Andes (Argentina/Chile), Sin Nombre (USA), Choclo (Panama), Laguna Negra (Paraguay)
First recognised: 1993, Four Corners, southwestern USA — a cluster of deaths among young Navajo people
Hemorrhagic Fever with Renal Syndrome (HFRS)
Where: Europe and Asia
What it does: Damages kidneys and blood vessels. Causes hemorrhaging, kidney failure, shock in severe cases.
Fatality: <1% (Puumala in Scandinavia) to 15% (Hantaan in Korea/China)
Key viruses: Hantaan (Korea/China), Dobrava (Balkans), Puumala (Scandinavia), Seoul (global — the only hantavirus carried by the common brown rat)
First recognised: Korean War, 1950-53 — 3,000+ UN soldiers fell ill near the Hantan River
The Andes exception
Every other hantavirus is a dead end in humans — the chain runs rodent → person and stops. Andes virus, carried by the long-tailed pygmy rice rat in southern Argentina and Chile, is the sole exception. It can pass from one person to another through close, sustained contact: sharing utensils, kissing, handling contaminated bedding, or breathing the same confined air during early illness.
This is not airborne transmission in the influenza sense. It requires proximity and duration — household contacts, intimate partners, healthcare workers without proper protection. But it is enough to create chains. The 2019 Epuyén cluster proved it: one infected person led to 34 cases and 11 deaths in a small Patagonian town. The MV Hondius proved it again, in a floating environment where 150 people shared every meal and corridor.
The rodent hosts
Each hantavirus is typically linked to a single rodent species that evolved alongside it. Andes virus belongs to the long-tailed pygmy rice rat (Oligoryzomys longicaudatus). Sin Nombre belongs to the deer mouse (Peromyscus maniculatus). Seoul virus is the outlier — carried by the common brown rat (Rattus norvegicus), which lives on every continent, making Seoul the only truly global hantavirus. This is why Seoul virus cases have appeared in pet rat owners in the UK and US, far from any endemic zone.
A virus older than its name
Retrospective analyses have found probable hantavirus cases in Europe dating to 1913 and in Asia from the 1930s. The virus got its name after South Korean virologist Dr Ho-Wang Lee isolated it from striped field mice near the Hantan River in 1978 — 25 years after thousands of Korean War soldiers had suffered the mysterious "Korean hemorrhagic fever."
The Americas discovered their own hantavirus story in May 1993, when unexplained deaths among young, healthy Navajo people in the Four Corners region led to Sin Nombre virus. The 2012 Yosemite outbreak (10 cases, 3 deaths linked to deer-mouse droppings in tent cabins) brought the virus into US mainstream awareness. And in 2019, Epuyén showed the world what Andes virus could do when human-to-human chains were allowed to form.
Global burden
WHO estimates 10,000 to 100,000 infections annually worldwide. China reports thousands of HFRS cases each year. Scandinavia sees hundreds of mild Puumala infections. The Americas report 300-500 HPS cases annually, mostly in Argentina and Chile. The true number is almost certainly higher — mild cases are routinely misdiagnosed as flu, and many endemic-zone infections go unreported.
Symptoms & when to seek care →