National Institute of Animal Health (NIAH)

Topics in Animal Health Research 2006

21. Genetic variations in the small RNA segment of the teratogenic Akabane virus

Japanese

 Characterization of the small RNA segment of the teratogenic Akabane virus was carried out to define the molecular epidemiology of the virus. With the exception of the African strain, the nucleotide and amino acid sequences were highly conserved among the isolates, irrespective of the year of isolation, source and geographical origin. On the basis of the nucleocapsid gene sequences of the segment, 170 field isolates were grouped into four distinct phylogenetic lineages reflecting geographical origin. The Japanese isolates were divided into two major clusters, one containing the strains isolated in the 1970s, 1988 to 1989, 1991, and 1994 to 1999, and the other containing strains isolated from 1982 to 1987, 1990, 1993, 1998, and 2000 to 2003 together with the Taiwanese and Israeli strains. The Asian strains seemed to have evolved in a common gene pool. The Australian and African strains were placed in the independent third and fourth clusters of the phylogenetic tree, respectively. No consecutive mutations have occurred on the small RNA segment of the Japanese isolates, indicating that the various genotypes of the virus might have been introduced continuously from an exotic source and that certain viruses adaptable to the Japanese environment might have spread transiently.
(Research Team for Environmental/Enzootic Diseases, TEL +81-99-268-2078)

Reference:

Yamakawa et al. (2006) Virus Res. 121 : 84-92.

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