Hantaviruses (family Bunyaviridae, genus Hantavirus) are rodent-borne, zoonotic (acquired from animals), enveloped RNA viruses, and include the causative agents of haemorrhagic fever with renal syndrome (HFRS). The viruses that cause HFRS include Hanta, Dobrava, Seoul, and Puumala. Dobrova and Hanta viruses cause a more severe HFRS with fever, haemorrhage, and renal failure, and a mortality rate of up to 15%. The mildest form of HFRS is caused by Puumala virus.