Phylogenetic Analysis and Isolation of Canine Distemper Viruses in Taiwan

Abstract

During the period from 2003 to 2005, two canine distemper virus (CDV) strains were isolated from 17 non-vaccinated puppies with suspected canine distemper by co-culture of peripheral blood mononuclear leucocytes and B95a cells. In addition, four cloned hemagglutinin (H) genes were obtained from 166 dogs infected with CDV. Indirect immunofluorescence assays and antigen tests confirmed that they were CDV. Analysis of the H genes of the six identified strains revealed that the deduced amino acid sequences contained nine potential sites for N-linked glycosylation, as had been found for H proteins of Japanese isolates. The seventh site is characteristic of the Taiwan strains described in this report and of recently reported Japanese strains. Furthermore, phylogenetic analysis of the H gene showed that the six isolates belong to the Asia-i group and are closely related to the recently reported Japanese and Chinese strains.