Analysis of Complete Puumala Virus Genome, Finland

Angelina Plyusnina, Maria Razzauti, Tarja Sironen, Jukka Niemimaa, Olli Vapalahti, Antti Vaheri, Heikki Henttonen, and Alexander Plyusnin

Author affiliations: Author affiliations: University of Helsinki and HUSLAB, Helsinki, Finland (A. Plyusnina, M. Razzauti, T. Sironen, O. Vapalahti, A. Vaheri, A. Plyusnin); Finnish Forest Research Institute, Vantaa, Finland (J. Niemimaa, H. Henttonen)

Abstract

Puumala virus causes nephropathia epidemica, a rodent-borne zoonosis that is endemic to Europe. We sequenced the complete Puumala virus genome that was directly recovered from a person who died and compared it with those of viruses from local bank voles. The virus strain involved was neither a unique nor rare genetic variant.

The outcome of a viral infection is determined by the agent’s pathogenicity and by host factors, such as genetic predisposition. For RNA viruses, which are notorious for their swift evolution and adaptation, a pathogen’s specific genotype usually is to blame for devastating effects (1). In many cases, however, the virus genome is not easy to search for particular mutations because recovery of complete viral sequences from clinical specimens remains extremely difficult. This is especially true for hantaviruses (family Bunyaviridae) that cause hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (2,3). Thus far, only a few complete hantavirus genomes originating from persons with clinical cases have been reported (4,5), and only 1 was recovered without passaging first in cell culture (4), which by itself can induce adaptive changes in the viral genome (6). We present the complete genome of PUUV directly recovered from a person with fatal infection.
Usually PUUV causes mild HFRS (also called nephropathia epidemica [NE]). In Finland, 1,000–3,000 NE cases are diagnosed annually, i.e., ≈60 cases/100,000 persons during years when the vole population peaks (7). Almost 100% of infected persons recover, and long-lasting complications are rare. The few fatal cases reported (8,9) showed no apparent geographic clustering. Thus, whether more severe illness could be connected to certain genetic variants of PUUV remains unknown.