ABSTRACT
Nephropathia epidemica (NE), an emerging rodent-borne disease caused by Puumala virus [1], has become an important cause of infectious acute renal failure in Europe, with sharp increases in incidence occurring for more than a decade [2]. Bank voles (Myodes glareolus) are the rodent reservoir of this hantavirus and are known to display cyclic population peaks [2]. Puumala virus is a member of the genus Hantavirus (family Bunyaviridae) that consist of 22 distinct hantavirus species [3]. Viruses of this genus are the only hemorrhagic fever viruses with a worldwide distribution, including the temperate regions of the northern hemisphere. Increased risk of human disease occurs through exposure to aerosolized excreta of infected wild rodents, which are the main reservoirs and carriers of hantaviruses in nature. Hantaviruses are the etiologic agents for two acute febrile disorders of man: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS) [4,5]. Both disorders are associated with initial acute thrombocytopenia and changes in vascular permeability, and both disorders may have pulmonary and/or renal symptoms [6]. Puumala virus, discovered in the late 1970s [1] is the most common cause of HFRS in Europe. The associated disease, often referred to as NE, is usually milder than Dobrava-Belgrade virus-associated disease with a fatality rate that varies from 0.1 to 0.3% [7]. It is noteworthy that Puumala virus strains from Japan, Korea, and China have been isolated from other vole species, but so far do not have known pathogenicity. Puumala virus infections thus remain prevalent west of the Ural mountains, except for the Asia slope of the Ural mountains in Bashkortostan, Russia [8]. Furthermore, the preferred biotope for bank voles are the
temperate forests of West and Central Europe, or the boreal forests (taiga) in Northern Europe, since vole thrive better in a wet habitat [9], explaining the absence of Puumala virusassociated disease in the Mediterranean coast region.
