Adler hantavirus, a new genetic variant of Tula virus identified in Major’s pine voles (Microtus majori) sampled in southern European Russia

Although at least 30 novel hantaviruses have been recently discovered in novel hosts such as shrews, moles and even bats, hantaviruses (family Bunyaviridae, genus Hantavirus) are primarily known as rodent-borne human pathogens. Here we report on identification of a novel hantavirus variant associated with a rodent host, Major’s pine vole (Microtus majori).Altogether 36 hantavirus PCR-positive Major’s pine voles were identified in the Krasnodar region of southern European Russia within the years 2008–2011. Initial partial L-segment sequence analysis revealed novel hantavirus sequences. Moreover, we found a single common vole (Microtus arvalis) infected with Tula virus (TULV). Complete S- and M-segment coding sequences were determined from 11 Major’s pine voles originating from 8 trapping sites and subjected to phylogenetic analyses.The data obtained show that Major’s pine vole is a newly recognized hantavirus reservoir host. The newfound virus, provisionally called Adler hantavirus (ADLV), is closely related to TULV. Based on amino acid differences to TULV (5.6–8.2% for nucleocapsid protein, 9.4–9.5% for glycoprotein precursor) we propose to consider ADLV as a genotype of TULV. Occurrence of ADLV and TULV in the same region suggests that ADLV is not only a geographical variant of TULV but a host-specific genotype. High intra-cluster nucleotide sequence variability (up to 18%) and geographic clustering indicate long-term presence of the virus in this region.