Ikuo Takashima

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In this study, tick-borne encephalitis (TBE) viruses from Siberia and far-eastern Asia were characterized in order to determine virus subtype distribution. TBE viruses were isolated from ticks (Ixodes persulcatus) collected in the far-eastern (Khabarovsk and Vladivostok) and Siberian (Irkutsk) regions of Russia in 1999. Phylogenetic analysis showed that(More)
Aedes japonicus (Theobald) was evaluated for competence as a vector of Japanese encephalitis virus and for its ability to transmit the virus vertically to its F1 larvae. Ae. japonicus supported the growth of the virus at 20 and 28 degrees C after feeding on a virus-blood mixture of 10(6.2) plaque forming unit (PFU)/ml. This species was able to transmit the(More)
Laboratory of Public Health, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, and Institute for Animal Experiment, School of Medicine, Hokkaido University, Sapporo, Department of Virology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, and Department of Neurology and Department of Respiratory Disease,(More)
We conducted field surveys of indigenous rodent species in Hokkaido, Japan from 1980 to 1993. Serum samples were collected from 663 rodents, including Clethrionomys rufocanus, Apodemus speciosus, A. argenteus, and C. rutilus. Antibody to hantavirus was determined by the protein G antibody assay. Positive C. rufocanus were detected in seven of eight(More)
Truncated recombinant nucleocapsid proteins (rNPs) of Hantaan virus (HTNV), Seoul virus (SEOV), and Dobrava virus (DOBV) were expressed by a baculovirus system. The truncated rNPs, which lacked 49 (rNP50) or 154 (rNP155) N-terminal amino acids of the NPs of HTNV, SEOV, and DOBV, were able to differentiate HTNV-, SEOV-, and DOBV-specific immune sera.(More)
To determine the vertebrate host of tick-borne encephalitis (TBE) virus in the southern part of Hokkaido, Japan, virus isolation was performed using spleens from small mammals captured in the area. Two virus strains were isolated, one strain from Apodemus speciosus and another from Clethrionomys rufocanus. Virus isolates were inoculated onto baby hamster(More)
We previously reported that small wild rodents in Japan harbor two types of novel Babesia microti-like parasites (designated as Hobetsu and Kobe types), but not the type commonly found in the northeastern United States (U.S. type) where human babesiosis is endemic. To determine whether these new types of parasites are distributed in places surrounding(More)
In an epizootiologic survey of 122 rodents captured in Vladivostok, Russia, antibodies positive for hantavirus were found in Apodemus peninsulae (4/70), A. agrarius (1/39), and Clethrionomys rufocanus (1/8). The hantavirus sequences identified in two seropositive A. peninsulae and two patients with hemorrhagic fever with renal syndrome (HFRS) from the(More)
  Seoul virus is a hantavirus that causes hemorrhagic fever with renal syndrome (HFRS). The virion has a tripartite (S, M, and L) negative-stranded RNA genome, which is characteristic of the family Bunyaviridae. However, the molecular basis of virus replication is not well known. We established a Northern blot hybridization (NB) procedure using(More)
Seroepizootiologic surveys among wild rodents were carried out in Japan and Far East Russia in 1995 and 1996. Seropositive animals were only identified in Clethrionomys rufocanus (23/134) in Hokkaido, Japan. On the other hand, seropositives were identified in C. rufocanus (1/8), Apodemus agrarius (2/66), Apodemus spp. (2/26) and Microtus fortis (3/22) in(More)