Nucleotide sequence analysis of nucleocapsid protein gene of canine distemper virus isolates in Thailand

The C-terminal part of the nucleocapsid protein gene of 13 canine distemper virus (CDV) isolates from Thailand, were analyzed. The nucleotide sequences were assigned to two clusters; cluster A exhibited a high degree of homology with the vaccine strain Onderstepoort, 99.10 and 97.61%, respectively, in the two isolates examined. Cluster B appeared closely related to virulent strains registered in the GeneBank database and to the virulent reference strain (A75/17); a total of 11 samples were analyzed, with 94.63-99.10% homology at the same position. The deduced amino acid sequences correlated with the two-nucleotide sequence clusters. However, there was no association among the CDV groups with histories of vaccination, sex, ages, clinical findings and evidence of viral antigen in tissues.