Publications by authors named "Katsunori Takayoshi"

Two virus strains, tentatively designated as ON-6/P/05 and ON-7/E/05, were isolated from blood samples of healthy cattle in the Yaeyama Islands, located in the southwestern-most region of Japan, in 2005. Ultrastructural observations of infected baby hamster (BHK-21) cells revealed that the viruses had features consistent with those of orbivirus. As with other orbiviruses, the viral genome consists of 10 double-stranded RNA segments.

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Background: In Japan, epizootic arboviral infections have severely impacted the livestock industry for a long period. Akabane, Aino, Chuzan, bovine ephemeral fever and Ibaraki viruses have repeatedly caused epizootic abnormal births and febrile illness in the cattle population. In addition, Peaton, Sathuperi, Shamonda and D'Aguilar viruses and epizootic hemorrhagic virus serotype 7 have recently emerged in Japan and are also considered to be involved in abnormal births in cattle.

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The G gene encoding the neutralization antigen of bovine ephemeral fever virus (BEFV) was characterized in order to define the virus's molecular epidemiology in Japan and the genetic relationships among the Japanese, Taiwanese and Australian isolates. The nucleotide and amino acid sequences of the gene were highly conserved among the Japanese strains, regardless of the year of isolation, and were closely related to the Taiwanese strains. By phylogenetic analysis, the Japanese and Taiwanese strains were classified clearly into three chronological clusters: 1966, 1984-1989 and 1996-2004, indicating that the epidemics of bovine ephemeral fever may occur almost simultaneously in both countries by the same genotype.

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