Lemhöfer et al.
Comparison of whole genomes of tick-borne encephalitis virus from mountainous alpine regions and regions with a lower altitude
Virus Genes. 2021; 57:217-221 doi.org/10.1007/s11262-020-01821-w

Over the last decades, a clear shift in the distribution of TBE virus from lower to higher altitudes has been observed. Possible effects on the genomic characteristics of TBE virus strains are still unclear, and it is open if mountainous strains have been naturally selected due to some small nucleotide polymorphisms in their genome that made them more adapted to the alpine environment.

Nine European subtype TBE strains isolated from mountainous regions (N= 5; above 500 m altitude: 563 m to 1364 m) and from plain (N= 4; less than 500 m altitude: 116 m to 459 m) were included in a study, and whole genome sequences were generated. The phylogenetic tree based on the nucleotide sequences (e.g., gE, prM/M, NS1, NS2B, NS3, NS4A, NS5) showed no evidence of a common origin of mountainous strains. The authors concluded that each strain was probably introduced individually into its location in higher altitudes, and the establishment of foci may be attributed to non-viral specific factors such as favorable conditions for vector species and host animals due to climate change.

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