Publications by authors named "Takeo Yamauchi"

Most members of the genus Orthonairovirus, represented by Crimean-Congo hemorrhagic fever virus and Nairobi sheep disease virus, are tick-borne, and some have become a public health concern in recent years. Here, we report the isolation and genetic and biological characterization of a new orthonairovirus, designated as "Iwanai Valley virus" (IWVV), from Ixodes ovatus ticks in Hokkaido, Japan. The amino acid sequence of the viral nucleoprotein (NP) was found to be 34-45% identical to those of known orthonairoviruses.

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  • The study investigates ixodid ticks associated with bat families in Eurasia, revealing significant genetic differences among tick species across different regions, particularly in Eastern Asia.
  • By conducting detailed morphological comparisons and analyzing molecular and phylogenetic relationships, the researchers identified and described three new tick species previously thought to be variations of existing ones.
  • The findings indicate that these new species exhibit high genetic divergence, particularly in the cytochrome oxidase subunit (coxI) gene, which supports their classification as separate species based on both genetic and morphological lines.
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  • Jingmen tick virus (JMTV) and Alongshan virus are emerging tick-borne viruses linked to human infections, found in various mammals and invertebrates, but their transmission cycles are not fully understood.
  • Recent surveillance in Japan identified JMTV and a new related virus, Takachi virus (TAKV), showing JMTV's widespread presence and persistence in certain regions over multiple years.
  • Evidence suggests that JMTV may be transmitted vertically in ticks, highlighting the need for further research to understand the infection risks associated with jingmenviruses in Japan.
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  • Tick-borne viruses are increasingly being identified globally, with advancements in high-throughput sequencing technology aiding their discovery.
  • This study utilized the Illumina MiniSeq to analyze the RNA virome of questing ticks from Japan, resulting in the isolation of several novel viruses, including two phleboviruses, one coltivirus, and one iflavirus.
  • Phylogenetic analysis indicated that certain recently discovered phleboviruses may be deficient in a specific genome segment, offering new insights into their evolution and potential as emerging pathogens.
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  • - Three similar isolates of a novel virus, named Tarumizu tick virus (TarTV), were discovered from hard ticks in Japan, showing they are closely related yet distinct strains.
  • - TarTV has a genome consisting of 12 double-stranded RNA segments, with 10 segments exhibiting similarities to proteins of other known tick-borne viruses, indicating it may belong to the Coltivirus genus.
  • - Electron microscopy revealed TarTV has a non-enveloped icosahedral structure, and while it can replicate in mammalian cells, it does not cause symptoms in infected mice, highlighting its potential for further study on genetic diversity within the Coltivirus family.
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Background: Spiders (Arachnida: Araneae) are a classic indicator taxon for evaluating the health of natural environments. However, studies of spiders' responses to forest succession under natural and anthropogenic disturbance regimes are lacking. Yakushima Island in southwestern Japan has a unique forest ecosystem, and part of the island is designated as a world natural heritage site by UNESCO.

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Background: Phylogeographical studies allow precise genetic comparison of specimens, which were collected over large geographical ranges and belong to the same or closely related animal species. These methods have also been used to compare ticks of veterinary-medical importance. However, relevant data are missing in the case of ixodid ticks of bats, despite (1) the vast geographical range of both Ixodes vespertilionis and Ixodes simplex, and (2) the considerable uncertainty in their taxonomy, which is currently unresolvable by morphological clues.

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Migratory birds may disperse parasites across ecological barriers, and recent climate change may alter the pattern of ectoparasite dispersal via changed patterns of bird migration. In order to document the parasitization of migratory birds by Ixodidae ticks on Jeju Island in Korea, we examined 934 migratory birds comprising 75 species for ticks from 2010 to 2012. In total, 313 ticks were collected from 74 migratory birds across 17 avian species and identified based on morphological keys.

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Ixodid ticks were collected from medium-sized to large mammals in Ehime Prefecture, Shikoku, Japan. Ten species of ticks (Amblyomma testudinarium, Dermacentor taiwanensis, Haemaphysalis flava, H. formosensis, H.

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During a mosquito collection, a female of the pigeon louse fly, Pseudolynchia canariensis (Diptera: Hippoboscidae), was collected by a mosquito trap baited with dry ice in Ishigaki-jima, Yaeyama Islands, Japan. This is the 1st record of P. canariensis from Yaeyama Islands.

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Nerocila japonica Schioedte & Meinert, 1881 is redescribed based on the holotype and specimens from various localities in Japanese waters. The following fishes are recorded as new hosts: Tribolodon hakonensis (Cyprinidae), Mugil cephalus, Liza affinis, Chelon haematocheilus (Mugilidae), Lateolabrax japonicus, L. latus (Lateolabracidae), Acanthopagrus latus, A.

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To determine the mechanisms of maintenance and evolution of Japanese encephalitis virus (JEV) in a temperate zone, we attempted to isolate JEV from mosquitoes and pigs in Toyama Prefecture, Japan. A total of 87 JEVs were isolated from female Culex tritaeniorhynchus mosquitoes and pigs during 2005-2009. The prevalence of JEV in Toyama Prefecture was seasonally late in comparison with that of the virus during 1966-1972.

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Endemic spotted fever group rickettsiosis was reported in Shimane Prefecture, Japan. From an analysis of 14 clinical cases found in the endemic area, the infectious agent of spotted fever group rickettsiosis was identified as Rickettsia japonica. In this study, we also found that Rickettsia japonica was highly infected with the vector tick, Haemaphysalis longicornis, in the endemic area.

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In field screening tests of synthetic pheromone candidates for Japanese sesiid species, a mixture of (3Z,13Z)-octadecadien-1-ol and (3Z,13Z)-octadecadienyl acetate successfully attracted male moths of Glossosphecia romanovi, a harmful pest of vine trees. The GC-EAD and GC-MS analyses of the pheromone gland extract revealed that the female moths produced the alcohol and acetate in a ratio of about 20:1, in addition to three other minor structure-related components.

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