NUCLEOTIDE-SEQUENCE OF THE ENVELOPE PROTEIN OF A TURKISH ISOLATE OF TICK-BORNE ENCEPHALITIS (TBE) VIRUS IS DISTINCT FROM OTHER VIRUSES OF THE TBE VIRUS COMPLEX

Turkish tick-borne encephalitis (TTE) virus causes an acute form of me ningoencephalomyelitis in sheep in the north-westem region of Turkey. The clinical syndrome resembles louping ill (LI) and the viruses respo nsible for both LI and TTE are members of the tick-borne encephalitis (TBE) complex of the Flaviviridae. The envelope protein gene of TTE vi rus was reverse-transcribed, amplified, cloned and sequenced. Alignmen t of the resultant sequence with those from other viruses of the TBE c omplex reveals that TTE virus is more closely related, at both nucleot ide and amino acid levels (84-6 % and 96 % respectively), to the Centr al European (CEE) subtype of the TBE virus, usually associated with hu man disease. The relationship with LI virus is more distant (83 % and 93.5 % respectively). These studies support the assertion that the ovi ne encephalomyelitis found in Turkey is caused by a virus that is gene tically distinct from known strains of both LI and CEE viruses and fro m a number of other known viruses of the TBE complex.