# Hantavirus

> Genus of segmented RNA viruses transmitted by wild rodents. In humans causes hantavirus pulmonary syndrome (Americas) or hemorrhagic fever with renal syndrome (Eurasia).

Canonical source: https://hantatracker.fr/en/glossary/hantavirus/

**Aliases**: hantavirus, orthohantavirus, hantaviridae

**Hantavirus** refers to any virus in the *Orthohantavirus* genus, family Hantaviridae, order Bunyavirales. These segmented RNA viruses naturally infect wild rodents, occasionally chiropterans and soricomorphs, without causing disease in the animal host. Transmission to humans is accidental, mainly through inhalation of contaminated aerosols. Human hantavirus diseases are rare but can be severe, with two main clinical forms depending on geographic area and strain.

## Classification and taxonomy

### Family and genus

Hantaviruses belong to the *Orthohantavirus* genus, which comprises **37 species** recognised by the International Committee on Taxonomy of Viruses (ICTV). This genus is part of the Hantaviridae family within the Bunyavirales order, which gathers several genera of segmented negative-sense RNA viruses. Each hantavirus is specifically associated with a primary host species, in which it establishes a chronic asymptomatic infection.

### Old World and New World hantaviruses

The major epidemiological distinction separates two groups:

- **Old World hantaviruses**: present in Asia, Europe and Africa, they mainly cause hemorrhagic fever with renal syndrome (HFRS). The major strains are Hantaan (Asia), Seoul (worldwide via the black rat), Puumala (Europe) and Dobrava (Balkans).
- **New World hantaviruses**: present in the Americas, they mainly cause hantavirus pulmonary syndrome (HPS). The major strains are Sin Nombre (North America), Andes (Argentina, Chile) and Laguna Negra (Paraguay, Bolivia).

## Hosts and reservoirs

### Diversity of host species

A reference study in reservoir virology lists **more than 80 host species** of hantaviruses worldwide: 51 rodent species, 7 chiropterans and 20 soricomorphs (shrews, moles). This diversity reflects long co-evolution between viruses and hosts, spanning several million years.

### Host-virus specificity

Each hantavirus is generally strictly associated with one host species. This specificity has two important practical consequences for public health: the geographic distribution of a hantavirus disease depends on the range of its reservoir, and surveillance of sentinel rodent populations allows anticipation of areas at risk for humans.

## Epidemiology

### Frequency

Hantavirus diseases remain rare zoonoses at the individual level. In the United States, the CDC records **890 cases** of hantavirus pulmonary syndrome from the start of surveillance in 1993 through the end of 2023, averaging 11 to 48 cases per year. In East Asia, hemorrhagic fever with renal syndrome is more frequent, with tens of thousands of cases reported annually in China.

### Risk factors

Exposure to hantaviruses depends on contact with rodents or their droppings. The main at-risk situations are agricultural activities, cleaning of unused buildings (basements, barns, hunting cabins), forestry work and travel to rural endemic areas. Rodent population density, which varies with climatic conditions, directly influences human risk.

## Surveillance and prevention

### International surveillance

WHO, ECDC and the US CDC coordinate international surveillance of hantavirus diseases. The CDC publishes annual national data, ECDC tracks cases in Europe and WHO documents events of international concern. Reports of unusual events feed the IHR (International Health Regulations) database in near real time.

### Prevention measures

Prevention relies on limiting exposure to wild rodents: building proofing, airtight food storage, wearing protective equipment when cleaning contaminated areas, ventilation and disinfection before intervention. No vaccine is internationally approved against American strains to date. Medical management relies on supportive care, in particular mechanical ventilation and ECMO in severe pulmonary forms.