Population genomics of louping ill virus provide new insights into the evolution of tick-borne flaviviruses

by Jordan J. Clark, Janice Gilray, Richard J. Orton, Margaret Baird, Gavin Wilkie, Ana da Silva Filipe, Nicholas Johnson, Colin J. McInnes, Alain Kohl, Roman Biek The emergence and spread of tick-borne arboviruses pose an increased challenge to human and animal health. In Europe this is demonstrated by the increasingly wide distribution of tick-borne encephalitis virus (TBEV,Flavivirus,Flaviviridae), which has recently been found in the United Kingdom (UK). However, much less is known about other tick-borne flaviviruses (TBFV), such as the closely related louping ill virus (LIV), an animal pathogen which is endemic to the UK and Ireland, but which has been detected in other parts of Europe including Scandinavia and Russia. The emergence and potential spatial overlap of these viruses necessitates improved understanding of LIV genomic diversity, geographic spread and evolutionary history. We sequenced a virus archive composed of 22 LIV isolates which had been sampled throughout the UK over a period of over 80 years. Combining this dataset with published virus sequences, we detected no sign of recombination and found low diversity and limited evidence for positive selection in the LIV genome. Phylogenetic analysis provided evidence of geographic clustering as well as long-distance movement, including movement events that appear recent. However, despite genomic data and an 80-year time span, we found that the data contained insufficient temporal signal to reliably estimate a mol...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research