In most locations except for Russia, tick-borne encephalitis is mainly caused by the European virus subtype. In 2015, fatal infections caused by European and Siberian tick-borne encephalitis virus subtypes in the same Ixodes ricinus tick focus in Finland raised concern over further spread of the Siberian subtype among widespread tick species.
Keywords: Encephalitis; Finland; TBEV; flavivirus infections; meningitis/encephalitis; tick-borne encephalitis virus; tickborne; vector-borne infections; viruses; zoonoses.