Papers - YAMADA Kentaro
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Mekata H., Yamamoto M., Kaneko Y., Yamada K., Okabayashi T., Saito A.
Pathogens 14 ( 3 ) 2025.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Pathogens
Severe fever with thrombocytopenia syndrome (SFTS), caused by infection with the SFTS virus, is an emerging fatal tick-borne zoonosis endemic to East Asia. Although SFTS is a tick-borne disease, the virus can be transmitted from animals with SFTS without a tick bite. Direct transmission of the SFTS virus from animals to humans has been reported; however, the transmission route is unclear in some cases. Therefore, this study focused on the possibility of SFTS virus transmission through urine and attempted to isolate the infectious virus from the urine of animals with SFTS. Since more efficient cell isolation is needed to determine whether the SFTS virus is present, we first expressed dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), the major receptor for the virus, in Vero cells (Vero-DC-SIGN cells) using a retroviral vector. When inoculated with equal amounts of the SFTS virus strain and SFTS-virus-infected animal serum, Vero-DC-SIGN cells had 42–136% and 20–85% more foci, respectively, than their parent Vero cells. After confirming that Vero-DC-SIGN cells were more suitable for the isolation of the SFTS virus, we investigated whether it could be isolated from the urine of eight cats and two dogs with SFTS. The virus was isolated from 25 μL of urine from two cats with SFTS. Considering that cats excrete 50–100 mL of urine per day, the transmission of the SFTS virus via the urine of cats with SFTS cannot be ruled out. Individuals examining or caring for cats suspected of having SFTS should be aware of the possibility of viral transmission via urine.
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Development of a Multi-Locus Real-Time PCR with a High-Resolution Melting Assay to Differentiate Wild-Type, Asian Recombinant, and Vaccine Strains of Lumpy Skin Disease Virus Reviewed International coauthorship
Bhakha K., Matsui Y., Buakhao N., Wanganurakkul S., Deemagarn T., Oba M., Takemae H., Mizutani T., Misawa N., Chintapitaksakul L., Yamada K., Suwankitwat N.
Veterinary Sciences 12 ( 3 ) 2025.3
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Veterinary Sciences
Lumpy skin disease virus (LSDV) affects cattle and causes significant economic damage. The live vaccine derived from an attenuated strain is effective but is associated with mild disease and skin lesions in some vaccinated cattle. Moreover, recombinant LSDV strains, particularly one with wild-type field and vaccine strains, have recently emerged and spread throughout Asian countries. A cost-effective LSDV typing method is required. We developed a multi-locus real-time PCR with a high-resolution melting (HRM) assay to differentiate between the wild-type, vaccine, and dominant Asian recombinant strains. Based on a multiple alignment analysis, we selected three target genes for the HRM assay, ORF095, ORF126, and ORF145, in which there are insertions/deletions and nucleotide substitutions between wild-type and vaccine strains, and designed primer sets for the assay. Using the synthetic DNA encoding these genes for the two strains, it was shown that the PCR amplicons intercalated with a saturating fluorescent dye could clearly differentiate between wild-type and vaccine strains in the HRM analysis for all three target genes. Further, using clinical samples, our method was able to identify recombinant strains harboring the wild-type ORF095 and ORF145 and the vaccine strain ORF126 genes. Thus, our HRM assay may provide rapid LSDV typing.
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Evaluation of lateral flow devices for rabies diagnosis in decomposed animal brain samples. Reviewed International coauthorship
Todoroki R, Ongtangco JT, Kimitsuki K, Saito N, Mananggit MR, Velasco CR, Mauhay JD, Garcia AM, Demetria CS, Kentaro Y, Nishizono A
Tropical medicine and health 53 ( 1 ) 30 2025.2
Language：English Publishing type：Research paper (scientific journal)
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Mekata H., Yamada K., Umeki K., Yamamoto M., Ochi A., Umekita K., Kobayashi I., Hirai T., Okabayashi T.
BMC Veterinary Research 20 ( 1 ) 190 2024.12
Language：English Publishing type：Research paper (scientific journal) Publisher：BMC Veterinary Research
Severe fever with thrombocytopenia syndrome (SFTS) is a fatal zoonosis caused by ticks in East Asia. As SFTS virus (SFTSV) is maintained between wildlife and ticks, seroepidemiological studies in wildlife are important to understand the behavior of SFTSV in the environment. Miyazaki Prefecture, Japan, is an SFTS-endemic area, and approximately 100 feral horses, called Misaki horses (Equus caballus), inhabit Cape Toi in Miyazaki Prefecture. While these animals are managed in a wild-like manner, their ages are ascertainable due to individual identification. In the present study, we conducted a seroepidemiological survey of SFTSV in Misaki horses between 2015 and 2023. This study aimed to understand SFTSV infection in horses and its transmission to wildlife. A total of 707 samples from 180 feral horses were used to determine the seroprevalence of SFTSV using enzyme-linked immunosorbent assay (ELISA). Neutralization testing was performed on 118 samples. In addition, SFTS viral RNA was detected in ticks from Cape Toi and feral horses. The overall seroprevalence between 2015 and 2023 was 78.5% (555/707). The lowest seroprevalence was 55% (44/80) in 2016 and the highest was 92% (76/83) in 2018. Seroprevalence was significantly affected by age, with 11% (8/71) in those less than one year of age and 96.7% (435/450) in those four years of age and older (p < 0.0001). The concordance between ELISA and neutralization test results was 88.9% (105/118). SFTS viral RNA was not detected in ticks (n = 516) or feral horses. This study demonstrated that horses can be infected with SFTSV and that age is a significant factor in seroprevalence in wildlife. This study provides insights into SFTSV infection not only in horses but also in wildlife in SFTS-endemic areas.
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Involvement of Campylobacter Species in Spotty Liver Disease-like Lesions in Broiler Chickens Detected at Meat Inspections in Miyazaki Prefecture, Japan Reviewed International coauthorship
Jiarpinitnun P., Iwakiri A., Fuke N., Pongsawat P., Miyanishi C., Sasaki S., Taniguchi T., Matsui Y., Luangtongkum T., Yamada K., Misawa N.
Microorganisms 12 ( 12 ) 2024.12
Language：English Publishing type：Research paper (scientific journal) Publisher：Microorganisms
Spotty liver disease (SLD) affects free-range laying hens, leading to mortality and reduced egg production. Campylobacter species, including Campylobacter hepaticus, have been associated with SLD cases worldwide. However, the cause of SLD-like lesions found in broilers in Japan still remains unclear. The present study aimed to investigate the involvement of Campylobacter spp. in broiler SLD by conducting microbiological, molecular biological, serological, histopathological, and immunohistopathological examinations using specimens of liver, bile, cecum, and serum from SLD-like and non-SLD chickens. C. jejuni was predominantly isolated and detected in approximately 40% of both non-SLD livers and SLD-like livers, with no significant difference between them. However, C. hepaticus was neither isolated nor detected in this study. Gross and histopathology revealed multifocal necrotizing hepatitis, suppurative granulomatous hepatitis, and cholangiohepatitis. Hepatitis stages are classified as no hepatitis, subclinical, acute, and chronic hepatitis. C. jejuni was more frequently present in acute-stage SLD-like livers, and high IgG antibody levels were noted in both subclinical and SLD-like-affected chickens, indicating C. jejuni infection. Immunohistochemical examination also supported these findings. The findings suggest that C. hepaticus was not involved in SLD-like in broilers in Japan, but C. jejuni translocation from the intestines to the liver may be a contributing factor.
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Kobayashi T., Takahashi M., Ohta S., Hoshino Y., Yamada K., Jirintai S., Primadharsini P.P., Nagashima S., Murata K., Okamoto H.
Viruses 16 ( 9 ) 2024.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Viruses
The zoonotic transmission of hepatitis E virus (HEV) genotypes 3 (HEV-3) and 4 (HEV-4), and rabbit HEV (HEV-3ra) has been documented. Vaccination against HEV infection depends on the capsid (open reading frame 2, ORF2) protein, which is highly immunogenic and elicits effective virus-neutralizing antibodies. Escherichia coli (E. coli) is utilized as an effective system for producing HEV-like particles (VLPs). However, research on the production of ORF2 proteins from these HEV genotypes in E. coli to form VLPs has been modest. In this study, we constructed 21 recombinant plasmids expressing various N-terminally and C-terminally truncated HEV ORF2 proteins for HEV-3, HEV-3ra, and HEV-4 in E. coli. We successfully obtained nine HEV-3, two HEV-3ra, and ten HEV-4 ORF2 proteins, which were primarily localized in inclusion bodies. These proteins were solubilized in 4 M urea, filtered, and subjected to gel filtration. Results revealed that six HEV-3, one HEV-3ra, and two HEV-4 truncated proteins could assemble into VLPs. The purified VLPs displayed molecular weights ranging from 27.1 to 63.4 kDa and demonstrated high purity (74.7–95.3%), as assessed by bioanalyzer, with yields of 13.9–89.6 mg per 100 mL of TB medium. Immunoelectron microscopy confirmed the origin of these VLPs from HEV ORF2. Antigenicity testing indicated that these VLPs possess characteristic HEV antigenicity. Evaluation of immunogenicity in Balb/cAJcl mice revealed robust anti-HEV IgG responses, highlighting the potential of these VLPs as immunogens. These findings suggest that the generated HEV VLPs of different genotypes could serve as valuable tools for HEV research and vaccine development.
DOI： 10.3390/v16091400
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Discovery of a new volcanic soil material, “Akahoya,” as an adsorbent for bacterial and viral pathogens and its application to environmental purification Reviewed International coauthorship
Pongsawat P., Jianpinitnun P., Sasaki S., Miyanishi C., Taniguchi T., Luangtongkum T., Yasui K., Kinoshita H., Kobayashi T., Nagahama H., Yamada K., Misawa N.
Applied and Environmental Microbiology 90 ( 9 ) e0100724 2024.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Applied and Environmental Microbiology
Akahoya is a volcanic soil rich in alumina, primarily deposited in Kyushu, Japan. We have found that Akahoya adsorbs bacteria in the water surrounding cattle grazing areas, suggesting a potential for environmental purification. This study investigated the spectrum of microorganisms adsorbed by Akahoya using a column filled with Akahoya through which a suspension of microorganisms was passed. Shirasu soil, another volcanic soil with a different chemical composition, was used as a control. Akahoya effectively adsorbed a diverse range of microorganisms including Escherichia coli, Campylobacter jejuni, Vibrio parahaemolyticus, Salmonella Enteritidis, Staphylococcus aureus, Clostridium perfringens, spores of Bacillus subtilis and Bacillus anthracis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), murine norovirus, and avian influenza virus (H3N2), whereas Shirasu soil did not adsorb any of the organisms examined. Moreover, bacteria naturally present in river water, such as aerobic bacteria, total coliforms, and Enterobacteriaceae as indicators of river contamination, as well as E. coli added artificially to sterilized river water, were reduced to below the detection limit (<1 CFU/mL) after being passed through Akahoya. Additionally, the number of viable E. coli continued to decrease after contact with Akahoya for 1 month, suggesting bactericidal effects. Notably, the adsorption of E. coli to Akahoya was influenced by the concentration of phosphate and the pH of the suspension due to the interaction between the surface phosphorylation of organisms and Al2O3, the major chemical component of Akahoya. The present results demonstrate the remarkable ability of Akahoya to remove phosphate and microbes, suggesting that Akahoya could be used for water purification processes. IMPORTANCE Although a safe and sufficient water supply is essential for the maintenance of hygienic conditions, a major challenge is to develop a comprehensive effective, sustainable, and cost-effective technological approach for the treatment and purification of contaminated water. In this study, we demonstrated that a novel volcanic soil, Akahoya, which has unlimited availability, is a highly effective adsorbent for a wide range of bacterial and viral pathogens, suggesting its potential as a sustainable resource for this purpose. It was suggested that the adsorption of microorganisms on Akahoya was mediated by phosphate groups present on the surface structures of microorganisms, which bind to the alumina component of Akahoya according to the phosphate concentration and pH of the liquid phase. The present findings highlight the exceptional ability of Akahoya to eliminate or reduce phosphate and microorganisms effectively in water purification processes, thus contributing to the development of efficient and sustainable solutions for addressing water pollution challenges.
DOI： 10.1128/aem.01007-24
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Complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021 Reviewed International coauthorship
Mekata H., Yamamoto M., Matsui Y., Niazi A.M., Yamada K., Okabayashi T., Cha S.Y., Jang H.K.
Microbiology Resource Announcements 13 ( 9 ) e0006024 2024.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Microbiology Resource Announcements
Here, we report the complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021, which was determined using the Illumina MiSeq platform. The position of the hemagglutinin-neuraminidase stop codon differed from that of the only other available completely sequenced prototype strain, duck/New York/22/1977.
DOI： 10.1128/mra.00060-24
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Puppies as the primary causal animal for human rabies cases: three-year prospective study of human rabies in the Philippines Reviewed International coauthorship
Saito N., Inton K.L., Mauhay J.D., Solante R.M., Guzman F.D., Yamada K., Kamiya Y., Saito-Obata M., Quiambao B.P., Yahiro T., Kimitsuki K., Nishizono A.
Frontiers in Microbiology 15 1425766 2024.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers in Microbiology
Introduction: While rabies remains a global concern, detailed studies on human rabies, particularly regarding causal animals and the reasons for not receiving postexposure prophylaxis (PEP), are lacking. Methods: We conducted a 3-year prospective study (October 2019–September 2022) at the Philippines’ largest rabies referral center. We interviewed patients with suspected rabies and their families. We used LN34 qRT-PCR and rapid fluorescent focus inhibition test on saliva samples. We also compared our findings with two retrospective studies at the same hospital. Results: We enrolled 151 patients, including 131 with potential rabies exposure. Similar to retrospective studies, the participants were predominantly males (75.5%), adults (76.8%), low-income individuals (91.4%), and rural dwellers (62.3%). The causal animals were mainly dogs (97.0%), with similar incubation periods, clinical symptoms, and a high proportion not receiving vaccines or immunoglobulins (93.2%). Most causal animals were owned by either the patients’ households or their neighbors (60.2%), with a significant proportion being puppies (58.8%). Most patients had knowledge of rabies; however, reasons for not seeking PEP included misconceptions about minor bites not causing rabies (51.3%), beliefs in traditional healers (33.9%), and economic constraints (22.6%). Despite completing the WHO regimen, two PEP failures were observed. LN34 qRT-PCR detected 98 positive cases (sensitivity, 64.9%; 95% CI 56.7–72.5). These strains belong to the Southeast Asia 4 subclade. Discussion: In conclusion, this study highlights the role of puppies as primary causal animals and the presence of misconceptions that preclude patients from acquiring PEP.
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Shirasaka Y., Yamada K., Etoh T., Noguchi K., Hasegawa T., Ogawa K., Kobayashi T., Nishizono A., Inomata M.
Pharmaceuticals 17 ( 1 ) 79 2024.1
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Pharmaceuticals
The outcomes of unresectable gastric cancer (GC) are unfavorable even with chemotherapy; therefore, a new treatment modality is required. The combination of an oncolytic virus and photodynamic therapy can be one of the promising modalities to overcome this. Mammalian orthoreovirus (MRV) is an oncolytic virus that has been used in clinical trials for several cancers. In this study, we developed and evaluated a recombinant MRV strain type 3 Dearing (T3D) that expresses membrane-targeting KillerRed (KRmem), a phototoxic fluorescent protein that produces cytotoxic reactive oxygen species upon light irradiation. KRmem was fused in-frame to the 3′ end of the σ2 viral gene in the S2 segment using a 2A peptide linker, enabling the expression of multiple proteins from a single transcript. RNA electrophoresis, Western blotting, and immunofluorescence analyses confirmed functional insertion of KRmem into the recombinant virus. The growth activity of the recombinant virus was comparable to that of the wild-type MRV in a cultured cell line. The recombinant virus infected two GC cell lines (MKN45P and MKN7), and a significant cytocidal effect was observed in MKN45P cells infected with the recombinant virus after light irradiation. Thus, recombinant MRV-expressing KRmem has the potential to serve as a novel treatment tool for GC.
DOI： 10.3390/ph17010079
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Development of a real-time RT-PCR system applicable for rapid and pen-side diagnosis of foot-and-mouth disease using a portable device, PicoGene® PCR1100. Reviewed International coauthorship
Matsui Y, Chottikamporn J, Ungvanijban S, Seeyo KB, Vitoonpong R, Suwankitwat N, Songkasupa T, Norimine J, Yamada K, Chintapitaksakul L, Misawa N
Journal of virological methods 319 114753 2023.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Virological Methods
Foot-and-mouth disease (FMD) is a highly contagious viral vesicular disease, causing devastating losses to the livestock industry. A diagnostic method that enables quick decisions is required to control the disease, especially in FMD-free countries. Although conventional real-time reverse transcription polymerase chain reaction (RT-PCR) is a highly sensitive method widely used for the diagnosis of FMD, a time lag caused by the transport of samples to a laboratory may allow the spread of FMD. Here, we evaluated a real-time RT-PCR system using a portable PicoGene PCR1100 device for FMD diagnosis. This system could detect the synthetic FMD viral RNA within 20 min with high sensitivity compared to a conventional real-time RT-PCR. Furthermore, the Lysis Buffer S for crude nucleic extraction improved the viral RNA detection of this system in a homogenate of vesicular epithelium samples collected from FMD virus-infected animals. Furthermore, this system could detect the viral RNA in crude extracts prepared using the Lysis Buffer S from the vesicular epithelium samples homogenized using a Finger Masher tube, which allows easy homogenization without any equipment, with a high correlation compared to the standard method. Thus, the PicoGene device system can be utilized for the rapid and pen-side diagnosis of FMD.
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ELGENDY Omnia, KITAHARA Go, YAMADA Kentaro, TANIGUCHI Shin, OSAWA Takeshi
Journal of Reproduction and Development advpub ( 0 ) 261 - 269 2023.8
Language：English Publishing type：Research paper (scientific journal) Publisher：The Society for Reproduction and Development
A high temperature-humidity index during summer has deleterious effects on mitochondrial function, reducing oocyte developmental competence. 5-Aminolevulinic acid (5-ALA) and sodium ferrous citrate (SFC) are both known to support mitochondrial function and have strong anti-oxidant and anti-apoptotic activities. This study aimed to determine the mechanism of action of 5-ALA/SFC on oocyte quality. Bovine oocytes were collected from medium-sized follicles during summer (July–September, temperature-humidity index:76.6), cultured with 0, 1, 2, 4, and 8 µM 5-ALA with SFC at a molar ratio of 1:0.125, fertilized, and cultured for 10 days. The addition of 8/1 µM 5-ALA/SFC had a deleterious effect on oocyte cleavage rate in comparison with control oocytes, but did not affect the blastocyst rate, while 1/0.125 µM 5-ALA/SFC had a significantly higher increase in blastocyst rate than 8/1 µM 5-ALA/SFC. The addition of 1/0.125 and 2/0.25 µM 5-ALA/SFC improved oocyte quality by increasing the mitochondrial distribution pattern and metaphase-II oocytes, reducing reactive oxygen species and upregulating <i>nuclear factor erythroid-2-related factor 2</i>, <i>heme oxygenase-1</i>, and <i>superoxide dismutase-1</i> in oocytes, and <i>nuclear factor erythroid-2-related factor 2</i> and <i>mitochondrial transcription factor A</i> in cumulus cells. These results indicate that 1/0.125 and 2/0.25 µM 5-ALA/SFC may support oocyte quality and developmental competence and provide anti-oxidant actions in cumulus-oocyte complexes.
DOI： 10.1262/jrd.2023-038
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Kaneko C., Shinohara A., Kikuchi T., Tokuda A., Irie T., Yamada K., Misawa N., Yoshida A.
Mammalian Biology 103 ( 4 ) 363 - 373 2023.8
Language：English Publishing type：Research paper (scientific journal) Publisher：Mammalian Biology
The Japanese badger (Meles anakuma) and the Japanese raccoon dog (Nyctereutes procyonoides viverrinus) are common wild animals in Japan. They are opportunistic omnivores that share similar foods and environments. Previous study has reported a difference in the isolation rates of a specific genus of bacteria from fecal samples of these animals inhabiting the same areas in Japan. This study hypothesized that badgers and raccoon dogs have different gut microbiota, which leads to different metabolisms of nutrients despite their similar ecological niches. This study aimed to verify this hypothesis by comparatively analyzing the gut microbiota of these species. Bacterial 16S rRNA amplicon sequencing analysis was performed using colonic contents collected from 12 badgers and 12 raccoon dogs. As a result, the gut microbiota in badgers and raccoon dogs were completely distinct. Phylum Firmicutes was the most abundant, followed by Proteobacteria, almost without Bacteroidota in badgers. In contrast, Firmicutes and Bacteroidota were abundant in raccoon dogs. Many species-characteristic bacterial taxonomic features were identified in each animal’s gut microbiota. Moreover, raccoon dogs exhibited richer and more diverse species in their gut microbiota than badgers. This study revealed that badgers and raccoon dogs have distinct gut microbiota, which possibly drives different metabolism, though they share similar foods and environments. Considering anatomical feature that badger lacks a cecum which raccoon dog has, the distinct structure of gut microbiota in badger and raccoon dog could be attributed to the differences in the physical structure of the gastrointestinal tract, even though diet and inhabiting environments are quite similar.
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Molecular Analysis of Rabies Virus Using RNA Extracted from Used Lateral Flow Devices Reviewed International coauthorship
Mauhay J.D., Saito N., Kimitsuki K., Mananggit M.R., Cruz J.L., Lagayan M.G., Garcia A.M., Lacanilao P.M., Yamada K., Saito-Obata M., Manalo D.L., Demetria C.S., Quiambao B.P., Nishizono A.
Journal of clinical microbiology 61 ( 3 ) e0154322 2023.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of clinical microbiology
Molecular analysis of rabies virus can provide accurate diagnosis and information on its genetic diversity. The transportation of rabies brain samples from remote areas to a central laboratory is challenging owing to biohazard risks and decomposability. We investigated the utility of used lateral flow devices (LFDs) for subsequent molecular analysis and assessed the necessary storage temperatures. Using RNA extracted from used LFD strips, we performed conventional reverse transcription-PCR (RT-PCR) using an LN34 primer set to amplify short fragments (165 bp) for rabies virus detection and the P1-304 primer set to amplify long fragments of the entire N gene amplicon (1,506 bp) for phylogenetic analysis. Among 71 used LFDs stored in a refrigerator and 64 used LFDs stored at room temperature, the LN34 assay showed high sensitivities (96.2% and 100%, respectively) for the diagnosis of rabies, regardless of the storage temperature. A significant reduction in the sensitivity of rabies diagnosis was observed when using the P1-304 primer set for used LFDs stored at room temperature compared to those stored at refrigeration temperature (20.9% versus 100%; P < 0.05). Subsequent sequencing and phylogenetic analysis were successfully performed using the amplicons generated by the P1-304 RT-PCR assays. Used LFDs are thus promising resources for rabies virus RNA detection and sequence analysis. Virus detection via RT-PCR, amplifying a short fragment, was possible regardless of the storage temperature of the used LFDs. However, refrigerated storage is recommended for RT-PCR amplification of long fragments for phylogenetic analysis.
DOI： 10.1128/jcm.01543-22
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Nosocomial Severe Fever with Thrombocytopenia Syndrome in Companion Animals, Japan, 2022 Reviewed
Mekata H., Umeki K., Yamada K., Umekita K., Okabayashi T.
Emerging Infectious Diseases 29 ( 3 ) 614 - 617 2023.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Emerging Infectious Diseases
In Japan, 2 cats that underwent surgery in a room where a sick dog had been euthanized became ill within 9 days of surgery. Severe fever with thrombocytopenia syndrome virus was detected in all 3 animals; nucleotide sequence identity was 100%. Suspected cause was an uncleaned pulse oximeter probe used for all patients.
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Mekata Hirohisa, Kawaguchi Takeshi, Iwao Kosho, Umeki Kazumi, Yamada Kentaro, Umekita Kunihiko, Okabayashi Tamaki
Japanese Journal of Infectious Diseases advpub ( 0 ) 211 - 214 2023.1
Language：English Publishing type：Research paper (scientific journal) Publisher：National Institute of Infectious Diseases
Severe fever with thrombocytopenia syndrome (SFTS) is caused by the severe fever with thrombocytopenia syndrome virus (SFTSV). Although SFTS is a fatal tick-borne zoonosis, it can infect humans without tick bite exposure. Recently, direct transmission of SFTSV from companion pets to humans has become a major problem. We present a case of SFTSV transmission from a dead community cat to a woman who buried the cat in Miyazaki Prefecture, Japan. The community cat died without a diagnosis of SFTS, and the woman buried it without taking any precautions. She developed symptoms of SFTS 9 days later. The woman tested positive for SFTS viral RNA and anti-SFTSV antibodies. The cat’s carcass was exhumed, and tissue samples were collected to confirm the viral infection. Numerous copies of viral RNA were detected. The SFTSV M segment sequences in the cat and the woman were 100% homologous. The woman claimed that she had touched blood that had leaked from the cat’s body while burying it. However, she could have been infected while transporting the cat to the animal hospital. This study highlights the risk of SFTSV infection from contact with sick or dead community cats.
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Fine Particle Adsorption Capacity of Volcanic Soil from Southern Kyushu, Japan. Reviewed International coauthorship
Misawa N, Yasui K, Sakai K, Kobayashi T, Nagahama H, Haraguchi T, Sasaki S, Torrung V, Luangtongkum T, Taniguchi T, Yamada K, Minamimagari M, Usami T, Kinoshita H
Nanomaterials (Basel, Switzerland) 13 ( 3 ) 2023.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Nanomaterials
“Akahoya” is a volcanic soil classified as a special soil deposited in Kyushu, Japan. Many of its properties are not yet clearly understood. We found that Akahoya had the potential to adsorb bacteria in cattle feces, which prompted us to investigate its material properties and perform experiments to comprehensively evaluate its adsorption performance for various fine particles such as acidic and basic dyes, NOx/SOx gas, and phosphoric acid ions, in addition to bacteria. Akahoya had a very high specific surface area owing to the large number of nanometer-sized pores in its structure; it exhibited a high adsorption capacity for both NO2 and SO2. Regarding the zeta potential of Akahoya, the point of zero charge was approximately pH 7.0. The surface potential had a significant effect on the adsorption of acidic and basic dyes. Akahoya had a very high cation exchange capacity when the sample surface was negatively charged and a high anion exchange capacity when the sample surface was positively charged. Akahoya also exhibited a relatively high adsorption capacity for phosphoric acid because of its high level of Al2O3, and the immersion liquid had a very high Al ion concentration. Finally, filtration tests were performed on Escherichia coli suspension using a column filled with Akahoya or another volcanic soil sample. The results confirmed that the Escherichia coli adhered on the Akahoya sample. The results of the Escherichia coli release test, after the filtration test, suggested that this adhesion to Akahoya could be phosphorus-mediated.
DOI： 10.3390/nano13030568
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SODA Kosuke, MEKATA Hirohisa, USUI Tatsufumi, ITO Hiroshi, MATSUI Yuto, YAMADA Kentaro, YAMAGUCHI Tsuyoshi, ITO Toshihiro
Journal of Veterinary Medical Science 85 ( 11 ) 1180 - 1189 2023
Language：English Publishing type：Research paper (scientific journal) Publisher：JAPANESE SOCIETY OF VETERINARY SCIENCE
In the winter of 2021–2022, multiple subtypes (H5N8 and H5N1) of high pathogenicity avian influenza viruses (HPAIVs) were confirmed to be circulating simultaneously in Japan. Here, we phylogenetically and antigenically analyzed HPAIVs that were isolated from infected wild birds, an epidemiological investigation of affected poultry farms, and our own active surveillance study. H5 subtype hemagglutinin (HA) genes of 32 representative HPAIV isolates were classified into clade 2.3.4.4b lineage and subsequently divided into three groups (G2a, G2b, and G2d). All H5N8 HPAIVs were isolated in early winter and had HA genes belonging to the G2a group. H5N1 HPAIVs belong to the G2b and G2d groups. Although G2b viruses were widespread throughout the season, G2d viruses endemically circulated in Northeast Japan after January 2022. Deep sequence analysis showed that the four HPAIVs isolated at the beginning of winter had both N8 and N1 subtypes of neuraminidase genes. Environmental water-derived G2a HPAIV, A/water/Tottori/NK1201-2/2021 (H5N8), has unique polymerase basic protein 1 and nucleoprotein genes, similar to those of low pathogenicity avian influenza viruses (LPAIVs). These results indicate that multiple H5 HPAIVs and LPAIVs disseminated to Japan via transboundary winter migration of wild birds, and HPAIVs with novel gene constellations could emerge in these populations. Cross-neutralization test revealed that G2a H5N8 HPAIVs were antigenically distinct from a G2b H5N1 HPAIV, suggesting that antibody pressure in wild birds was involved in the transition of the HPAIV groups during the season.
DOI： 10.1292/jvms.23-0121
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Kaneko Chiho, Mekata Hirohisa, Irie Takao, Yamada Kentaro, Misawa Naoaki, Umekita Kunihiko, Okabayashi Tamaki, Umeki Kazumi, Putu Eka Sudaryatma
Ticks and tick-borne diseases 14 ( 2 ) 102115 2022.12
Language：English Publishing type：Research paper (scientific journal)
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Development of an oncolytic mammalian orthoreovirus expressing the near-infrared fluorescent protein iRFP720. Reviewed International journal
Katsuhiro Ogawa, Kentaro Yamada, Tsuyoshi Etoh, Masahiro Kitagawa, Yoshinori Shirasaka, Kazuko Noguchi, Takeshi Kobayashi, Akira Nishizono, Masafumi Inomata
Journal of virological methods 308 114574 - 114574 2022.10
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)
Fluorescence-guided surgery (FGS) is a useful method for removing invasive tumor tissues. For this, near-infrared (NIR) fluorescence probes are suitable for visualizing cancer cells due to their low autofluorescence, and an oncolytic mammalian orthoreovirus (MRV) expressing an NIR fluorescent protein is expected to be a novel tool for FGS. In this study, we identified the optimal insertion site of the NIR fluorescent protein gene iRFP720 (915 nt) in the MRV genome. We constructed genome plasmids for the L1, M1, and S2 segments, where a gene cassette comprising iRFP720 and T2A self-cleaving peptide was inserted in the 5' or 3' region of each segment. Through virus recovery, the recombinant MRV with the gene cassette at the M1 segment's 3' end, T3D-L(M1/3'iRFP720), was capable of replication and passaging with bright NIR fluorescence. However, the replication of T3D-L(M1/3'iRFP720) was approximately 1,000-fold lower than that of the wild-type virus. T3D-L(M1/3'iRFP720) production improved due to the transfection of a fusion-associated small transmembrane protein gene of fusogenic reovirus. Further, fluorescence signals were detected in T3D-L(M1/3'iRFP720)-infected human gastric and pancreatic cancer cells. Thus, the M1 segment's 3' end tolerates the expression of the long iRFP720 gene, which may propel the development of recombinant MRV vectors for FGS.