THE VIRUS CAUSING ENCEPHALOMYELITIS IN SHEEP IN SPAIN - A NEW MEMBER OF THE TICK-BORNE ENCEPHALITIS GROUP

The nucleotide and deduced primary amino acid sequence of the envelope gene of two virus isolates from the brains of Spanish sheep with ence phalomyelitis, were determined and compared with those of other flaviv iruses. The amino acid alignments showed that the Spanish Viruses shar ed 95 to 96 per cent homology with the envelope protein of louping ill virus and western European tick-borne encephalitis virus. in comparis on, the maximum variation in amino acid identities among strains of lo uping ill Virus from the British Isles is 1.8 per cent. The Spanish is olates were distinguishable from all other known flaviviruses by the p resence of st unique tripeptide sequence (AQR) at amino acid positions 232 to 234 in the E protein, the position at which a genetic marker f or distinct flavivirus species has been identified. Other genetic mark ers, viz DSGHD (amino acids 320 to 324) and EHLPTA (amino acids 207 to 212), which identify the tick-borne encephalitis group within the gen us Flavivirus, were present in the amino acid sequences of the Spanish virus. It is concluded that the cause of sheep encephalomyelitis in S pain is a distinct species in the tick-borne encephalitis virus group.