Co-circulation of two Puumala hantavirus lineages in Latvia: a Russian lineage described previously and a novel Latvian lineage.

Puumala hantavirus (PUUV) causes a mild form of haemorrhagic fever with renal syndrome in Europe. Seven genetic lineages of PUUV have thus far been recorded, which exhibit geographic structure within the distribution of its natural host, the bank vole (Myodes glareolus). This study presents evidence for two distinct PUUV lineages co-circulating in Latvia: one previously described from Russia and a novel one that appears to be endemic. The Latvian lineage (LAT) is considerably divergent and several amino acid markers make it easily distinguishable. Phylogenetic analysis suggested a possibility of different evolutionary histories for the PUUV genome segments of LAT.