Hantaviruses are rodent-borne agents belonging to the Bunyaviridae family. These viruses, which are found throughout Europe, Asia and the Americas, are maintained by different species of rodents, in which they produce chronic, inapparent infections. Humans become infected through contact with urine, saliva or faeces from infected rodents, mainly via the aerosol route. In humans, clinical disease occurs in the form of two major syndromes: haemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary syndrome (HPS). Haemorrhagic fever with renal syndrome mainly occurs in Europe and Asia and HPS has only ever been reported in the Americas. Person-to-person transmission of hantaviruses, although uncommon, was described during an outbreak of HPS in southern Argentina. Most epidemics of HFRS and HPS occur in areas with large populations of rodents that have a relatively high prevalence of infection.