Isolation and characterization of Dobrava hantavirus carried by the striped field mouse (Apodemus agrarius) in Estonia

Dobrava hantavirus (DOB) was isolated from the striped field mouse (Apodemu s agrarius) trapped on Saaremaa Island, Estonia, and its genetic and antige nic characteristics were subsequently analysed. Phylogenetic analysis showe d that the Estonian DOE strain, together with several wild strains carried by Apodemus agrarius, forms a well-supported lineage within the DOE clade. The topography of the trees calculated for the S, M and L nucleotide sequen ces of the Estonian DOE suggests a similar evolutionary history for all thr ee genes of this virus and, therefore, the absence of heterologous reassort ment in its evolution, A cross-neutralization comparison of the Estonian vi rus with the prototype DOE, isolated from a yellow-necked mouse (A. flavico llis) in Slovenia, revealed 2- to 4-fold differences in the end-point titre s of rabbit and human antisera, When studied with a panel of 25 monoclonal antibodies (MAbs), the Estonian and Slovenian DOE isolates showed similar a ntigenic patterns that could be distinguished by two MAbs, Genetic comparis on showed sequence differences in all three genome segments of the two DOE isolates, including an additional N-glycosylation site in the deduced seque nce of the G2 protein from the Estonian virus. Whether any of these mutatio ns relates to the different rodent hosts rather than to the distant geograp hical origin of the two isolates remains to be resolved. Taken together, ou r observations suggest that A, agrarius, which is known to harbour Hantaan virus in Asia, carries another hantavirus, DOE, in north-east Europe.