DISTRIBUTION AND GENETIC-HETEROGENEITY OF PUUMALA VIRUS IN SWEDEN

Small mammals trapped in Sweden were analysed for specific antibody re sponses against three hantavirus serotypes and for the presence of vir al antigen. To determine the genetic identity of viral RNA in lungs of seropositive bank voles (Clethrionomys glareolos), polymerase chain r eactions and subsequent partial sequencing of both the M and S segment s were employed. The sequences obtained were all identified as Puumala (PUU) virus, with a high degree of heterogeneity between the differen t geographical localities. Alignment of nucleotide and deduced amino a cid sequences, together with phylogenetic analysis, showed that PUU vi ruses circulating in central Sweden were distinct from those in the no rthern region. The localization of the two distinct PUU virus genotype s was shown to correlate with the postglacial recolonization of Sweden by bank voles.