Puumala virus (PUUV) is a negative-stranded RNA virus in the genusHantavirus, family Bunyaviridae. Puumala virus (PUUV) is a species of hantavirus. Humans infected with the virus may develop a haemorrhagic fever with renal syndrome (HFRS) known as nephropathia epidemica. Puumala virus HFRS is lethal in less than 0.5% of the cases.