Abstract

Twenty-nine (29) Israeli bluetongue virus isolates belonging to eight different serotypes (BTV-2, 4, 5, 8, 12, 15, 16, and 24) were selected to study the nucleotide sequences of segment 9 encoding VP6 protein and the non-structural protein, NS4. Phylogenetic analysis revealed that all Israeli BTV isolates were subdivided into three main groups, of which the 1^st and 2^nd groups each comprised at least three clusters. Each of the clusters A, B, C, D, and G contained only one serotype – BTV-24, 4, 8, 16, and 15, respectively – whereas clusters E and F each included several different serotypes. Cluster E contained viruses belonging to serotypes BTV-2, 5, and 16; cluster F contained viruses belonging to serotypes BTV-12, 8, and 24. Coding by segment 9 (VP6) proteins varied amongst Israeli isolates, whereas NS4 was highly conserved. The clinical manifestations of the disease did not correlate with the amino acid sequence of VP6 or NS4 proteins.

Key words: Bluetongue virus, Israel, sequence analysis, VP6, NS4