Publications by authors named "Meiko Kubo"

8 Publications

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Bovine Respiratory Syncytial Virus Enhances the Adherence of to Bovine Lower Respiratory Tract Epithelial Cells by Upregulating the Platelet-Activating Factor Receptor.

Front Microbiol 2020 31;11:1676. Epub 2020 Jul 31.

Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki, Japan.

Coinfection by bovine respiratory syncytial virus (BRSV) and (PM) frequently has been observed in cattle that develop severe pneumonia. We recently reported that BRSV infection significantly increased PM adherence to bovine lower respiratory tract epithelial cells. However, the molecular mechanisms of enhanced PM adherence are not completely understood. To investigate whether BRSV infection regulates any cellular adherence receptors on bovine bronchus- and lung-epithelial cells, we performed proteomic and functional analyses. The proteomic analysis showed that BRSV infection increased the accumulation of the platelet-activating factor receptor (PAFR) in both cell types. Molecular experiments, including specific blockade, knockdown, and overexpression of PAFR, indicated that PM adherence to these cell types depended on PAFR expression. These findings highlight the role, in cattle with severe pneumonia, of the synergistic effect of coinfection by BRSV and PM in the lower respiratory tract.
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http://dx.doi.org/10.3389/fmicb.2020.01676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7411089PMC
July 2020

Bovine Respiratory Syncytial Virus Decreased Pasteurella multocida Adherence by Downregulating the Expression of Intercellular Adhesion Molecule-1 on the Surface of Upper Respiratory Epithelial Cells.

Vet Microbiol 2020 Jul 2;246:108748. Epub 2020 Jun 2.

Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki, Japan; Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan; Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan. Electronic address:

The synergistic infection of bovine respiratory syncytial virus (BRSV) and Pasteurella multocida (PM) may predispose cattle to develop severe pneumonia. Previously, we reported that BRSV infection significantly decreased PM adherence to the upper respiratory epithelial cells. It may allow bacteria to invade into the lower respiratory tract and lead to severe pneumonia. To investigate whether BRSV infection regulates the cell surface adherence receptor on bovine trachea epithelial cells (bTECs), we performed proteomic and functional analyses. BRSV infection decreased the expression of intercellular adhesion molecule-1 (ICAM1) on bTECs. Inhibition and knockdown experiments using anti-ICAM1 antibody and siRNAs targeting ICAM1 indicated that PM adherence to bTECs was dependent on ICAM1 expression. These data suggest that under normal conditions bTECs may capture PM in the upper respiratory tract, while BRSV infection reverses this mechanism. The proposed gateway function of bTECs is disrupted by BRSV infection that may facilitate bacterial invasion into the lower respiratory tract and lead to secondary or more severe respiratory infection.
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http://dx.doi.org/10.1016/j.vetmic.2020.108748DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7265823PMC
July 2020

Slaughterhouse survey for detection of bovine viral diarrhea infection among beef cattle in Kyushu, Japan.

J Vet Med Sci 2019 Oct 5;81(10):1450-1454. Epub 2019 Aug 5.

Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan.

Bovine viral diarrhea virus (BVDV) footprint has spread across the globe and is responsible for one of the most economically important diseases in cattle. In Japan, some regional surveillance and preventive measures to control bovine viral diarrhea (BVD) have been implemented. However, BVDV infection is poorly understood in cattle industries, and there is no systematic BVD surveillance system and control program. Kyushu is the center for raising beef cattle in Japan. Therefore, this study aimed to determine the BVDV infection using a slaughterhouse survey among beef cattle in Kyushu, Japan. A total of 1,075 blood samples were collected at two regional slaughterhouses in Miyazaki prefecture from December 2015 to June 2016. Antigen ELISA was used for detection of BVDV antigen in blood samples. Two samples showed positive results (2/1,075; 0.18%). BVDV RNA was extracted from positive blood samples; the sequence was determined and analyzed by the neighbor-joining method for construction of the phylogenetic tree. Phylogenetic analysis based on the 5'-UTR revealed that the two positive samples were grouped into the same subtype BVDV-1b in the BVDV-1 genotype, but the infected cattle belonged to two different farms. In conclusion, this is the first study to identify the presence of BVDV in a slaughterhouse survey in Kyushu. These findings suggest that a slaughterhouse survey is a useful tool for developing a surveillance system for monitoring infectious diseases in cattle.
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http://dx.doi.org/10.1292/jvms.19-0045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6863731PMC
October 2019

Co-infection of epithelial cells established from the upper and lower bovine respiratory tract with bovine respiratory syncytial virus and bacteria.

Vet Microbiol 2019 Aug 12;235:80-85. Epub 2019 Jun 12.

Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan; Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan. Electronic address:

Bovine respiratory disease complex is a major disease affecting the global cattle industry. Multiple infections by viruses and bacteria increase disease severity. Previously, we reported that bovine respiratory syncytial virus (BRSV) infection increases adherence of Pasteurella multocida to human respiratory and bovine kidney epithelial cells. To examine the interaction between the virus and bacteria in bovine respiratory cells, we generated respiratory epithelial cell lines from bovine trachea (bTEC), bronchus (bBEC), and lung (bLEC). Although all established cell lines were infected by BRSV and P. multocida susceptibility differed according to site of origin. The cells derived from the lower respiratory tract (bBEC and bLEC) were significantly more susceptible to BRSV than those derived from the upper respiratory tract (bTEC). Pre-infection of bBEC and bLEC with BRSV increased adherence of P. multocida; this was not the case for bTEC. These results indicate that BRSV may reproduce better in the lower respiratory tract and encourage adherence of bacteria. Thus, we identify one possible mechanism underlying severe pneumonia.
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http://dx.doi.org/10.1016/j.vetmic.2019.06.010DOI Listing
August 2019

Detection of neutralizing antibody against porcine epidemic diarrhea virus in subclinically infected finishing pigs.

J Vet Med Sci 2018 Nov 2;80(11):1782-1786. Epub 2018 Oct 2.

Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan.

The purpose of this study was to detect porcine epidemic diarrhea virus (PEDV) subclinically infected pigs shipped from non-case farms to slaughterhouses. Systematic sampling was conducted at two slaughterhouses. A total of 1,556 blood samples were collected from 80 case and non-case farms from pigs over 6 months old. Blood samples were centrifuged to obtain sera. Serial serum dilutions were subjected to serological examination for PEDV presence using Neutralization test (NT). The cut-off titer was set at titer of 1:2 dilution and farms with at least one positive sample in duplicate were classified as PED-positive farms. Several non-case farms (9.4%, 6/64) and 100% (16/16) of the case farms were indeed positive for PEDV. The proportion of seropositive animals from case farms was 63.7%, significantly different from that of non-case farms (4.3%, P<0.05). In both case and non-case farms, the proportion of seropositive animals in farrow-to-finish farms was significantly higher than in wean-to-finish farms (P<0.05). Seropositive animals in non-case farms were detected by NT in a sero-survey by sampling at slaughterhouses. Therefore, subclinically infected pigs should be considered prior to shipment.
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http://dx.doi.org/10.1292/jvms.18-0132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6261828PMC
November 2018

Bovine respiratory syncytial virus infection enhances Pasteurella multocida adherence on respiratory epithelial cells.

Vet Microbiol 2018 Jul 30;220:33-38. Epub 2018 Apr 30.

Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan; Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan. Electronic address:

Primary infection with bovine respiratory syncytial virus (BRSV) predisposes cattle to secondary infection with bacteria that cause bovine respiratory disease complex (BRDC). However, the interaction between BRSV and bacteria is unclear. This in vitro study examined the adherence of Pasteurella multocida (PM) to BRSV-infected cells was assessed in colony forming unit assays, by flow cytometry analysis, and by indirect immunofluorescence analysis (IFA) of epithelial cells (A549, HEp-2, and MDBK). An in vitro model based on infection of BRSV-infected epithelial cells revealed that PM adherence to BRSV-infected cells was 2- to 8-fold higher than uninfected cells. This was confirmed by flow cytometry analysis and IFA. Epithelial cell expression of mRNA encoding cytokines and chemokines increased after exposure to PM, but increased further after co-infection with BRSV and PM. BRSV-mediated adherence of PM to epithelial cells may underlie the serious symptoms of BRDC.
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http://dx.doi.org/10.1016/j.vetmic.2018.04.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7117154PMC
July 2018

Growth and genotypes of Echinococcus granulosus found in cattle imported from Australia and fattened in Japan.

Parasitol Int 2011 Dec 10;60(4):498-502. Epub 2011 Sep 10.

Laboratory of Veterinary Parasitic Diseases, Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.

At the abattoir on study in Miyazaki, Japan, 9537 imported cattle from Australia in average were slaughtered annually in the last 5 years (2006 to 2010) and hydatid cysts were constantly detected in about 1.8% of the cattle. In order to assess the risk of Echinococcus granulosus delivered to Japan by imported cattle, 250 cysts found in 103 cattle at the abattoir were examined for their biological characteristics and genotypes. The cattle slaughtered were imported from Australia at an age of 10-12 months old and fattened for 17-18 months in Japan. The cysts showed their size ranging from 4 to 108 mm and were mainly found in the lung. Mature protoscoleces were detected in the three largest cysts, all were of the G1 genotype. Most of the other cysts contained clear cyst fluid and had thin laminated layer with no protoscoleces. The finding implies a potential risk of E. granulosus being established in Japan, thus strict and proper meat inspection and consequent offal condemnation are requisite at abattoirs that deal with imported cattle. Genotyping based on partial fragments of mitochondrial cox1, rrnS and nad1 genes were performed on the 66 cysts, showing that most of the cysts were G1 genotype (common sheep strain). However, two and four cysts were considered as G2 (Tasmanian sheep strain) and G3 (buffalo strain) genotypes, respectively. Since it has been widely recognized that G1 is the only genotype distributing in mainland Australia and that G2 genotype has been eradicated from Tasmania, the finding of those genotypes from Australian cattle indicated that certain genotypes other than G1 genotype are distributing in mainland Australia.
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http://dx.doi.org/10.1016/j.parint.2011.09.002DOI Listing
December 2011

Enumeration and identification of Campylobacter species in the liver and bile of slaughtered cattle.

Int J Food Microbiol 2007 Sep 7;118(3):259-63. Epub 2007 Aug 7.

Department of Veterinary Public Health, Faculty of Agriculture, Miyazaki University, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan.

Healthy cattle are considered as reservoirs for a variety of Campylobacter species. To control the bacterial contamination in meat products, quantitative assessment of campylobacters in liver and gallbladder was carried out at an abattoir. Liver and bile samples were collected from 108 healthy beef cattle after evisceration and viable counts of campylobacters were determined by a direct-plating technique using modified Cefoperazone Charcoal Deoxycholate agar (mCCDA). The suspected colonies on the highest dilution plates were subjected to biochemical tests and PCR for identification. Campylobacter species were isolated from 49 (45%) bile and 6 (5%) liver specimens examined. Numbers of campylobacters in bile and liver ranged from log(10)3 to 7 (median 5) and log(10) 1 to 2 (median 1) cfu per ml and per g, respectively. These Campylobacter species were identified as C. fetus, C. jejuni, and C. coli. Multiple infections involving two species were observed in 16 cattle. C. fetus and C. jejuni were the predominant species in bile. Growth of C. fetus, C. jejuni, and C. coli in spiked bile samples revealed an initial exponential growth phase followed by a period with no apparent increase in colony count for 28 days. It appeared that these campylobacters can survive in bile for a long period. To determine transfer route of bacterial cells to the gallbladder, C. jejuni, C. fetus, or C. coli was inoculated intravenously in mice. The inoculated cells were recovered from bile, suggesting that the organism was transferred from the blood stream to bile duct in the liver. From these results, bile in cattle is considered to be an important contamination source of Campylobacter species in processing plants.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2007.07.057DOI Listing
September 2007