Genotypes of Canine Distemper Virus Determined by Analysis of the Hemagglutinin Genes of Recent Isolates from Dogs in Japan

Abstract

Canine distemper of domestic dogs is caused by canine distemper virus (CDV), a member of the morbilliviruses. It has been a highly contagious disease of great veterinary importance for centuries, but for the last several decades it has been controlled satisfactorily by modified live vaccines. In the 1990s, however, it was described that CDV strains genetically different from vaccine strains may have caused the disease in vaccinated dogs. The highest antigenic variation is found in the H protein. Therefore, in the present study, hemagglutinin (H) genes obtained from current vaccines and field isolates and amplified directly from clinical specimens were genetically analyzed by restriction fragment length polymorphism assay and sequencing. Phylogenetic analysis of the H-gene amino acid sequences revealed that at least two CDV genotypes are circulating among dogs in Japan; one is a genotype to which almost all Japanese CDV isolates belong and the other has not been previously described. Both are separate and independent from the other lineages or genotypes of vaccine strains, as well as European and U.S. CDV isolates. The results suggest that CDV has also evolved in Japan, and further studies will be needed for an evaluation and possible improvement of the efficacies of current CDV vaccines.

Detection and differentiation of field and vaccine strains of canine distemper virus using reverse transcription followed by nested real time PCR (RT-nqPCR) and RFLP analysis

“…A similar procedure, using RFLP analysis of the NC gene, was proposed previously to differentiate between vaccine and field strains in China (Wang et al, 2011). Other studies have proposed RFLP analysis for CDV differentiation, although all of them involved the more variable haemagglutinin (H) gene as the target (Mochizuki et al, 1999;Calderon et al, 2007;Di Francesco et al, 2012).…”

Development of a combined canine distemper virus specific RT-PCR protocol for the differentiation of infected and vaccinated animals (DIVA) and genetic characterization of the hemagglutinin gene of seven Chinese strains demonstrated in dogs

“…This genotype appears to be predominant throughout China, and is infecting domestic dogs as well as raccoon dog species. Asia-1 CDV strains have also been detected in Japan (Mochizuki et al, 1999), Taiwan (Chan et al, 2009;Lee et al, 2010), and Korea .…”

Genetic diversity of Hungarian canine distemper virus strains

“…In this study, the authors analyzed nucleic acid sequences of virus strains from different parts of Hungary along with other CDV sequences deposited in the GenBank by researchers from all over the world. Since the hemagglutinin (H) gene shows the greatest extent of genetic variation that allows distinction of various lineages (Haas et al, 1997;Harder and Osterhaus, 1997;Mochizuki et al, 1999;Iwatsuki et al, 2000;Uema et al, 2005;Martella et al, 2006), the authors designed a primer pair that allowed the complete amplification of the H gene. Due to the fact that several lineages can be present during the same time within one geographic region (Haas et al, 1999;Lan et al, 2005), and the fact that the possibility of point mutations at the attachment site of the primers is relatively high for the H gene, a more conserved region of the viral genome, the large polymerase (L) gene was targeted for diagnostic purposes.…”