Distribution of Puumala hantavirus in Denmark: analysis of bank voles (Clethrionomys glareolus) from Fyn and Jutland

Abstract

The majority of hantaviral infections in Denmark since 1957 have occurred on the island of Fyn. We have recently shown the presence of Puumala hantavirus (PUUV) in bank voles (Clethrionomys glareolus) on Fyn. To learn more about the distribution and prevalence of PUUV in Denmark, 310 small mammals, belonging to six rodent and two insectivore species, were trapped in four localities on Fyn and three localities on the Jutland Peninsula (mainland Denmark), where only a few cases of nephropathia epidemica (NE) have been confirmed so far. Serum samples (heart extracts) from all animals were initially analyzed for the presence of hantavirus-specific antibodies (Ab) by enzyme immunoassay, and lung tissue samples of bank voles for the presence of the viral nucleocapsid protein antigen by immunoblotting. Altogether 11 Ab-positive rodents were found, all of them bank voles from Fyn. PUUV genome sequences (nucleotides 2,168-2,569 from the medium genomic segment) were recovered by reverse transcription-polymerase chain reaction from seven bank voles. They showed an overall diversity up to 5% and formed a well-supported genetic lineage on the phylogenetic tree with a clustering of two strains from southeastern Fyn together and a separation from the one strain from western Fyn. Our data confirmed the circulation of PUUV in both the southeastern and western parts of the island, known to have the highest numbers of human NE cases.