In this contribution, our attention is mainly focused on the evolutionary relationships between W-TBEV, SSEV and LIV. W-TBEV is widely distributed throughout continental Europe and Russia, SSEV is endemic to Spain [2] [3] [4] [5] [6] 8] , and LIV, initially considered to be restricted to the British Isles and Ireland [2] [3] [4] [5] [6] , has now been reported from Norway [2] and Denmark [9, 10] . The ecology and pathogenesis of both W-TBEV and LIV have been intensively investigated [11, 12] , whereas studies dedicated to SSEV are scarce.