TOHOKU UNIVERSITY Researchers

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Michiko Okamoto

Section

Graduate School of Medicine

Job title

Senior Assistant Professor

Degree

researchmap

https://researchmap.jp/viro

J-GLOBAL ID

201801001348983274

Professional Memberships 3

THE JAPANESE SOCIETY FOR PEDIATRIC INFECTIOUS DISEASES
THE JAPANESE ASSOCIATION FOR INFECTIOUS DISEASES
THE JAPANESE SOCIETY FOR VIROLOGY

Research Interests 2

ウイルスの分子疫学
ウイルス感染症の病態

Research Areas 2

Life sciences / Hygiene and public health (laboratory) /
Life sciences / Virology /

Papers 87

Hypothalamic-pituitary-adrenal dynamics in early-stage COVID-19 observed in a case with arginine vasopressin deficiency. International-journal

Hinako Kirikae, Yuta Tezuka, Michiko Okamoto, Ginji Furuta, Kei Omata, Yoshikiyo Ono, Tetsuhiro Tanaka, Fumitoshi Satoh

BMC endocrine disorders　25　(1)　169-169　2025/07/08

DOI： 10.1186/s12902-025-01992-3 　

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BACKGROUND: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on pituitary function remains unclear, particularly during the acute phase of coronavirus disease 2019 (COVID-19). CASE PRESENTATION: We report the case of a 40-year-old man with arginine vasopressin deficiency (central diabetes insipidus) who was admitted for the evaluation of anterior pituitary function. The patient developed mild COVID-19 during the hospitalization, when we inadvertently observed rapid activation of the hypothalamic-pituitary-adrenal (HPA) axis prior to the onset of fever. At the estimated onset of COVID-19, the patient's body temperature and the serum level of C-reactive protein remained within normal limits, whereas plasma ACTH levels drastically elevated, and subsequently, serum cortisol levels remain consistently high throughout the day, resulting in increased urinary free cortisol. The serum levels of several cytokines, including IFN-γ, IL-1RA, IL-6, and TNF-α, were also significantly elevated compared to those in the non-infected state. Acute suppression of thyroid and gonadal functions was observed approximately one day after the HPA axis activation. CONCLUSIONS: These findings illustrate the rapid response of the HPA axis to inflammatory factors in the early-stage COVID-19, which may have important implications for understanding the initial host responses to SARS-CoV-2 infection.
Validation of the United States isolation termination criteria using virus culture results of the omicron variant in Japan. International-journal

Issei Seike, Hiroaki Baba, Michiko Okamoto, Asami Nakayama, Tetsuji Aoyagi

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy　31　(6)　102714-102714　2025/06

DOI： 10.1016/j.jiac.2025.102714 　

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Cycle threshold (Ct) values obtained from real-time reverse-transcription polymerase chain reaction (RT-PCR) tests are commonly used to determine COVID-19 isolation discharge from hospitals. However, not all patients with low Ct values are infectious, and studies evaluating infectivity through virus cultures in Japan remain limited. This study assessed patients with Ct values <30 at 10 days after symptom onset and compared the clinical characteristics of seven patients with positive virus culture results and 11 patients with negative virus culture results to validate the Centers for Disease Control and Prevention (CDC) isolation criteria in Japan. Among non-immunosuppressed patients with mild-to-moderate COVID-19, 80 % were virus culture-negative 10 days after symptom onset, even when the Ct values were <30. In contrast, only 33 % of patients with severe-to-critical symptoms tested negative on virus culture. All immunosuppressed patients with severe-to-critical symptoms consistently tested positive in virus cultures. Notably, three patients with hematological disorders remained virus culture-positive 20 days after symptom onset. These findings generally align with the CDC criteria. For non-immunosuppressed patients with mild-to-moderate COVID-19, isolation release after 10 days is supported without the need for additional RT-PCR testing. However, for non-immunosuppressed patients with severe-to-critical symptoms and immunocompromised patients, particularly those with hematological disorders, isolation may be safely discontinued when Ct values exceed 30 after 10 days. This study provides valuable insights into identifying individuals suitable for isolation release based on SARS-CoV-2 testing in Japan.
Molecular analysis of influenza A(H3N2) in a remote tropical island during 2014-2019 to identify the frequency of introduction and local circulation. International-journal

Sikandar Azam, Takeaki Imamura, Michiko Okamoto, Yusuke Sayama, Mayuko Saito, Mariko Saito-Obata, Clyde Dapat, Raita Tamaki, Christina Dahlia Joboco, Joanna Ina Manalo, Samantha Louise Bado, Joanne De Jesus Cornejo, Socorro Lupisan, Marianette Inobaya, Veronica Tallo, Beatriz P Quiambao, Hitoshi Oshitani

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases　154　107864-107864　2025/05

DOI： 10.1016/j.ijid.2025.107864 　

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BACKGROUND: The sources of new antigenic Influenza A(H3N2) variants and the role of tropical regions in the global A(H3N2) circulation remain unclear. By conducting molecular analysis, this study aimed to identify A(H3N2) introduction events and the duration of local circulation in a geographically remote tropical island. METHODS: Nasopharyngeal/nasal samples were collected from symptomatic children under 5 years old in a remote tropical island of the Philippines between 2014 and 2019. From the 330 A(H3N2) strains detected, 150 were sequenced for the Hemagglutinin 1 (HA1) gene. Time-scaled Bayesian phylogenetic analysis identified introduction events from global A(H3N2) circulation. We estimated the duration of local circulation and its association with detected amino acid substitutions. RESULTS: Six different A(H3N2) clades/subclades circulated during the study period. Of the 15 introduction events identified during this period, 13 resulted in local circulation lasting less than 3 months, while one led to 5-month-long circulation. Another 10-month-long local circulation event, by definition, was more likely the result of two distinct introduction events with local circulation lasting less than 3 months, respectively. Most amino acid substitutions that emerged during local circulation were sporadic. No fixed substitutions appeared at the seven key amino acid sites for antigenic changes, suggesting that introduced strains were maintained without the emergence of new antigenic variants. CONCLUSION: In our study population, A(H3N2) circulation resulted from multiple introduction events, followed by local circulation lasting less than 3 months, with occasional long-term persistence. Our study indicates that tropical regions may contribute to maintaining globally circulating strains but may not be a source of antigenic variants.
Prolonged RSV circulation in 2022 to 2023 associated with the emergence of a novel RSV-B clade in Biliran, Philippines. International-journal

Joanne de Jesus-Cornejo, Ruth Anne B Hechanova-Cruz, Johanna Beulah T Sornillo, Michiko Okamoto, Hitoshi Oshitani

The Journal of infection　90　(4)　106467-106467　2025/04

DOI： 10.1016/j.jinf.2025.106467 　
Norovirus-associated diarrhea and asymptomatic infection in children aged under 4 years: a community-cohort study in the Philippines. International-journal

Chuyao Yu, Maria Carmen A Corpuz, Joseph M Bonifacio, Makiko Kishi, Takeaki Imamura, Yusuke Sayama, Mariko Saito-Obata, Clyde Dapat, Michiko Okamoto, Hitoshi Oshitani, Mayuko Saito

IJID regions　14　100549-100549　2025/03

DOI： 10.1016/j.ijregi.2024.100549 　

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OBJECTIVES: This study aimed to estimate the incidence of norovirus (NoV)-associated diarrhea and asymptomatic infections in children under 4 years of age and identify the genotypes of multiple NoV infections. METHODS: A community-based cohort study was conducted in Tarlac, Philippines. Children aged 0-2 years were followed up for 2 years. The prevalence and incidence rates of NoV-associated diarrhea and asymptomatic infections were calculated. Risk factors were assessed using the Cox proportional hazards model. The genotypes and immunotypes of repeated infections were tabulated. RESULTS: A total of 338 children aged 6208 child-months were analyzed. NoV was detected in 17.4% (84 of 527, 95% confidence interval [CI]: 12.7-19.7%) of diarrheal episodes and 10.8% (219 of 2031, 95% CI: 9.4-12.3%) of asymptomatic stool samples. The highest incidence of NoV-associated diarrhea occurred in children aged 6-11 months (2.31 per 100 child-months, 95% CI: 1.30-3.32) and 18-23 months (2.34 per 100 child-months, 95% CI: 1.57-3.12), whereas the highest incidence of asymptomatic NoV infection was observed in children aged 12-23 months (4.49 per 100 child-months, 95% CI: 3.41-5.56). Repeated NoV infections were detected between different genotypes, except in two children who had repeated NoV GI.3 and two children with GI.9 infections. CONCLUSIONS: Children had the highest risk of NoV-associated diarrhea during their first year of life, whereas asymptomatic NoV infections persisted after the second year. Repeated NoV infections suggest genotype-specific immunity after NoV infection.
Serological analyses against endemic human coronaviruses and SARS-CoV-2 in children and adults using samples collected before the COVID-19 pandemic. International-journal

Yusuke Sayama, Chuan Lo, Hiroki Tomizawa, Mayuko Saito, Michiko Okamoto, Suguru Ohmiya, Hidekazu Nishimura, Hitoshi Oshitani

IJID regions　13　100485-100485　2024/12

DOI： 10.1016/j.ijregi.2024.100485 　

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OBJECTIVES: Four endemic human coronaviruses (HCoVs), HCoV-229E, HCoV-NL63, HCoV-HKU1, and HCoV-OC43, infect humans during childhood and cause the common cold. COVID-19 caused by SARS-CoV-2 leads to mild symptoms in children, possibly owing to the protection conferred by immunity developed during a previous HCoV infection. This study analyzed the seroreactivity of four endemic HCoVs and SARS-CoV-2 in children and adults. METHODS: A total of 747 serum samples (from individuals aged 6 months to 69 years) were collected from 2015 to 2019 before the COVID-19 pandemic in Japan. The samples were tested for immunoglobulin G antibodies against the four endemic HCoVs and SARS-CoV-2 wild-type spike ectodomain proteins using enzyme-linked immunosorbent assay. RESULTS: The seroprevalence of endemic HCoVs (except HCoV-229E) showed 90% positivity by 3-4 years old, whereas HCoV-229E seroprevalence was observed at 8 years old. Approximately 35% of the samples showed reactivity to SARS-CoV-2 and did not change with age. However, the children's group presented higher antibody levels than the adult group. The sample reactivity against SARS-CoV-2 did not confirm neutralization capability. CONCLUSIONS: The reactive samples against SARS-CoV-2 showed varying antibody levels among different age groups. These findings may contribute to a deeper understanding of the clinical symptoms of COVID-19 and coronavirus diseases.
Characterization of human respiratory syncytial virus in children with severe acute respiratory infection before and during the COVID-19 pandemic. International-journal

Paul Simusika, Michiko Okamoto, Clyde Dapat, Walter Muleya, Moffat Malisheni, Sikandar Azam, Takeaki Imamura, Mayuko Saito, Innocent Mwape, Evans Mpabalwani, Mwaka Monze, Hitoshi Oshitani

IJID regions　11　100354-100354　2024/06

DOI： 10.1016/j.ijregi.2024.03.009 　

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OBJECTIVES: Annual outbreaks of human respiratory syncytial virus (HRSV) are caused by newly introduced and locally persistent strains. During the COVID-19 pandemic, global and local circulation of HRSV significantly decreased. This study was conducted to characterize HRSV in 2018-2022 and to analyze the impact of COVID-19 on the evolution of HRSV. DESIGN/METHODS: Combined oropharyngeal and nasopharyngeal swabs were collected from children hospitalized with severe acute respiratory infection at two hospitals in Zambia. The second hypervariable region of the attachment gene G was targeted for phylogenetic analysis. RESULTS: Of 3113 specimens, 504 (16.2%) were positive for HRSV, of which 131 (26.0%) and 66 (13.1%) were identified as HRSVA and HRSVB, respectively. In early 2021, an increase in HRSV was detected, caused by multiple distinct clades of HRSVA and HRSVB. Some were newly introduced, whereas others resulted from local persistence. CONCLUSIONS: This study provides insights into the evolution of HRSV, driven by global and local circulation. The COVID-19 pandemic had a temporal impact on the evolution pattern of HRSV. Understanding the evolution of HRSV is vital for developing strategies for its control.
Identification of Various Recombinants in a Patient Coinfected With the Different SARS-CoV-2 Variants. International-journal

Yusuke Sayama, Akie Sakagami, Michiko Okamoto, Masahiro Sakamoto, Hikari Koizumi, Yoko Kimura, Clyde Dapat, Mayuko Saito, Yuko Suzuki, Mie Sasaki, Naoko Sugawara, Hitoshi Oshitani

Influenza and other respiratory viruses　18　(6)　e13340　2024/06

DOI： 10.1111/irv.13340 　

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BACKGROUND: Viral recombination that occurs by exchanging genetic materials between two viral genomes coinfecting the same host cells is associated with the emergence of new viruses with different virulence. Herein, we detected a patient coinfected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta and Omicron variants and identified various recombinants in the SARS-CoV-2 full-length spike gene using long-read and Sanger sequencing. METHODS: Samples from five patients in Japan with household transmission of coronavirus disease 2019 (COVID-19) were analyzed using molecular assays for detection and identification of SARS-CoV-2. Whole-genome sequencing was conducted using multiplex PCR with short-read sequencing. RESULTS: Among the five SARS-CoV-2-positive patients, the mutation-specific assay identified the Delta variant in three, the Omicron variant in one, and an undetermined in one. The undermined patient was identified as Delta using whole-genome sequencing, but samples showed a mixed population of Delta and Omicron variants. This patient was analyzed for viral quasispecies by long-read and Sanger sequencing using a full-length spike gene amplicon. In addition to the Delta and Omicron sequences, the viral quasispecies analysis identified nine different genetic recombinant sequences with various breakpoints between Delta and Omicron sequences. The nine detected recombinant sequences in the spike gene showed over 99% identity with viruses that were detected during the Delta and Omicron cocirculation period from the United States and Europe. CONCLUSIONS: This study demonstrates that patients coinfected with different SARS-CoV-2 variants can generate various viral recombinants and that various recombinant viruses may be produced during the cocirculation of different variants.
Severe pneumonia due to Legionella and SARS-CoV-2 co-infection necessitating medical evacuation from a cargo ship. International-journal

Shiori Kitaya, Hiroaki Baba, Michiko Okamoto, Masahiro Sakamoto, Asami Nakayama, Yumiko Takei, Issei Seike, Kentarou Takei, Kengo Oshima, Koichi Tokuda, Takuya Shiga, Hajime Kanamori

Journal of travel medicine　30　(5)　2023/09/05

DOI： 10.1093/jtm/taad067 　
Lack of zoonotic coronavirus species detected among children hospitalized with pneumonia in the Philippines. International-journal

Yusuke Sayama, Michiko Okamoto, Mayuko Saito, Raita Tamaki, Mariko Saito-Obata, Reynaldo Frederick Negosa Quicho, Christina Dahlia Joboco, Socorro Lupisan, Hitoshi Oshitani

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America　2023/07/20

DOI： 10.1093/cid/ciad430 　
Rapid Detection of SARS-CoV-2 RNA Using Reverse Transcription Recombinase Polymerase Amplification (RT-RPA) with Lateral Flow for N-Protein Gene and Variant-Specific Deletion-Insertion Mutation in S-Protein Gene. International-journal

Jose L Malaga, Monica J Pajuelo, Michiko Okamoto, Emmanuel Kagning Tsinda, Kanako Otani, Pablo Tsukayama, Lucero Mascaro, Diego Cuicapuza, Masamichi Katsumi, Kazuhisa Kawamura, Hidekazu Nishimura, Akie Sakagami, Yo Ueki, Suguru Omiya, Satoshi Okamoto, Asami Nakayama, Shin-Ichi Fujimaki, Chuyao Yu, Sikandar Azam, Eiichi Kodama, Clyde Dapat, Hitoshi Oshitani, Mayuko Saito

Viruses　15　(6)　2023/05/26

DOI： 10.3390/v15061254 　

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Rapid molecular testing for severe acute respiratory coronavirus 2 (SARS-CoV-2) variants may contribute to the development of public health measures, particularly in resource-limited areas. Reverse transcription recombinase polymerase amplification using a lateral flow assay (RT-RPA-LF) allows rapid RNA detection without thermal cyclers. In this study, we developed two assays to detect SARS-CoV-2 nucleocapsid (N) gene and Omicron BA.1 spike (S) gene-specific deletion-insertion mutations (del211/ins214). Both tests had a detection limit of 10 copies/µL in vitro and the detection time was approximately 35 min from incubation to detection. The sensitivities of SARS-CoV-2 (N) RT-RPA-LF by viral load categories were 100% for clinical samples with high (>9015.7 copies/µL, cycle quantification (Cq): < 25) and moderate (385.5-9015.7 copies/µL, Cq: 25-29.9) viral load, 83.3% for low (16.5-385.5 copies/µL, Cq: 30-34.9), and 14.3% for very low (<16.5 copies/µL, Cq: 35-40). The sensitivities of the Omicron BA.1 (S) RT-RPA-LF were 94.9%, 78%, 23.8%, and 0%, respectively, and the specificity against non-BA.1 SARS-CoV-2-positive samples was 96%. The assays seemed more sensitive than rapid antigen detection in moderate viral load samples. Although implementation in resource-limited settings requires additional improvements, deletion-insertion mutations were successfully detected by the RT-RPA-LF technique.
Seroprevalence of four endemic human coronaviruses and, reactivity and neutralization capability against SARS-CoV-2 among children in the Philippines. International-journal

Yusuke Sayama, Michiko Okamoto, Mayuko Saito, Mariko Saito-Obata, Raita Tamaki, Christine Dahlia Joboco, Socorro Lupisan, Hitoshi Oshitani

Scientific reports　13　(1)　2310-2310　2023/02/09

DOI： 10.1038/s41598-023-29072-3 　

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Four endemic human coronaviruses (HCoV), HCoV-229E, HCoV-NL63, HCoV-HKU1, and HCoV-OC43, are closely related to SARS-CoV-2. These coronaviruses are known to infect humans living in temperate areas, including children under 5 years old; however, the seroprevalence of four HCoVs among children in tropical areas, including the Philippines, remains unclear. This study aimed to assess the prevalence of antibodies against four HCoVs and to determine the reactivity and neutralization of these antibodies against SARS-CoV-2 among children in the Philippines. A total of 315 serum samples collected from 2015 to 2018, before the emergence of SARS-CoV-2, in Biliran island, Philippines, were tested for the presence of antibodies against four HCoVs and SARS-CoV-2 using recombinant spike ectodomain proteins by IgG-enzyme-linked immunosorbent assay (ELISA). Reactivity to and neutralization of SARS-CoV-2 were also investigated. The seroprevalence of the four HCoVs was 63.8% for HCoV-229E, 71.4% for HCoV-NL63, 76.5% for HCoV-HKU1, and 83.5% for HCoV-OC43 by ELISA. Age group analysis indicated that seropositivity to all HCoVs reached 80% by 2-3 years of age. While 69/315 (21.9%) of the samples showed reactive to SARS-CoV-2, almost no neutralization against SARS-CoV-2 was detected using neutralization assay. Reactivity of antibodies against SARS-CoV-2 spike protein obtained by ELISA may not correlate with neutralization capability.
Comparison of Rhinovirus A-, B-, and C-Associated Respiratory Tract Illness Severity Based on the 5'-Untranslated Region Among Children Younger Than 5 Years. International-journal

Akiko Sayama, Michiko Okamoto, Raita Tamaki, Mariko Saito-Obata, Mayuko Saito, Taro Kamigaki, Yusuke Sayama, Irene Lirio, Joanna Ina G Manalo, Veronica L Tallo, Socorro P Lupisan, Hitoshi Oshitani

Open forum infectious diseases　9　(10)　ofac387　2022/10

DOI： 10.1093/ofid/ofac387 　

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BACKGROUND: Rhinoviruses (RVs) are among the most frequently detected viruses from hospitalized children with severe acute respiratory infections, being classified into RV-A, RV-B, and RV-C (4 clades: C, GAC1, GAC2, and A2). This study aimed to compare the clinical characteristics and respiratory tract illness severity between the RV species and RV-C clades in children in primary care and hospital settings in rural communities in the Philippines. METHODS: Clinical samples and information of children <5 years old in the Philippines were collected from 2014 to 2016. The samples were tested by reverse-transcription polymerase chain reaction (RT-PCR) targeting the 5'-untranslated region. PCR-positive samples were sequenced, and RV species were identified by phylogenetic analysis. RESULTS: Overall, 3680 respiratory tract illness episodes in 1688 cohort children were documented; 713 of those were RV positive and identified as RV-A (n = 271), RV-B (n = 47), and RV-C (n = 395: C [n = 76], GAG1 [n = 172], GAG2 [n = 8], A2 [n = 138], and unidentified [n = 1]). Severe illnesses, low oxygen saturation, cough, and wheezing were more common in patients with RV-C, especially with GAC1, than in those with RV-A or RV-B. Furthermore, severe illness was significantly more common in RV-C (GAC1)-positive cases than in RV-A-positive cases (odds ratio, 2.61 [95% CI, 1.17-4.13]). CONCLUSIONS: Children infected with RV-C had more severe illnesses than children infected with RV-A and RV-B. Moreover, emerging clades of RV-C were associated with increased severity.
Practical Validation of United States Centers for Disease Control and Prevention Assays for the Detection of Human Respiratory Syncytial Virus in Pediatric Inpatients in Japan

Reiko Suwa, Yohei Kume, Miyuki Kawase, Mina Chishiki, Takashi Ono, Sakurako Norito, Ko Sato, Michiko Okamoto, Satoru Kumaki, Yukio Nagai, Mitsuaki Hosoya, Makoto Takeda, Hidekazu Nishimura, Koichi Hashimoto, Kazuya Shirato

Pathogens　11　(7)　754-754　2022/07/01
Publisher: MDPI AG
DOI： 10.3390/pathogens11070754 　

eISSN： 2076-0817

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The World Health Organization initiated a global surveillance system for respiratory syncytial virus (RSV) in 2015, and the pilot surveillance is ongoing. The real-time RT-PCR RSV assays (Pan-RSV and duplex assays) developed by the United States Centers for Disease Control and Prevention are applied as the standard assays. To introduce these as standard assays in Japan, their practicality was evaluated using 2261 specimens obtained from pediatric inpatients in Japan, which were collected from 2018 to 2021. Although the Pan-RSV and duplex assays had similar analytical sensitivities, they yielded 630 (27.9%) and 786 (34.8%) RSV-positive specimens, respectively (p < 0.001). Although sequencing analysis showed mismatches in the reverse primer used in the Pan-RSV assay, these mismatches did not affect its analytical sensitivity. The analysis of read numbers of RSV isolates from air–liquid interface culture of human bronchial/tracheal epithelial cells showed that the duplex assay had a greater number of reads than did the Pan-RSV assay. Therefore, the duplex assay has superior detection performance compared with the Pan-RSV assay, but the two assays have similar analytical sensitivities.
Prolonged shedding of infectious viruses with haplotype switches of SARS-CoV-2 in an immunocompromised patient. International-journal Peer-reviewed

Kosuke Shoji, Akira Suzuki, Michiko Okamoto, Emmanuel Kagning Tsinda, Naoko Sugawara, Mie Sasaki, Yoshihiko Nogami, Michio Kobayashi, Hitoshi Oshitani, Masaru Yanai

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy　28　(7)　1001-1004　2022/04/07

DOI： 10.1016/j.jiac.2022.04.004 　

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A concern has been raised that the persistent COVID-19 infection in an immunocompromised host can be the source of the SARS-CoV-2 variants. This is the case of a 61-year-old man in complete remission of a follicular lymphoma after six cycles of rituximab and bendamustine with additional two cycles of rituximab completed eight months prior to the episode of COVID-19 pneumonia. The patient's respiratory failure was long-lasting, and required mechanical ventilation until day 75. Acquired immunity tested negative throughout the observational period. The viral RNA was detectable until day 100 while the infectious virus was isolated until day 79. Seven haplotypes were identified and the non-synonymous mutations accumulated in the spike gene which included E484Q and S494P. In the management of COVID-19 cases with suppressed immune statuses, initial evaluation of existing immunity and monitoring for infectiousness throughout the clinical course including the convalescent stage may be necessary.
Serotype Identification of Human Adenoviruses Associated with Influenza-Like Illnesses in the Philippines from 2006-2012 by Microneutralization and Molecular Techniques. International-journal Peer-reviewed

Catherine Calzado-Dacasin, Janiza Lianne Foronda, Vina Lea Arguelles, Chona Mae Daga, Marie Therese Quimpo, Socorro Lupisan, Clyde Dapat, Mariko Saito, Michiko Okamoto, Pia Marie Albano, Hitoshi Oshitani

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases　117　326-333　2022/04

DOI： 10.1016/j.ijid.2022.02.008 　

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OBJECTIVES: Human adenoviruses (HAdV) are known to cause a wide range of diseases including acute respiratory infections, conjunctivitis, and acute gastroenteritis. In this study, we aimed to determine the serotypes of HAdV in patients with influenza-like illness (ILI) in the Philippines from 2006-2012 and to describe the demographic and epidemiological characteristics of patients who tested positive for HAdV. METHODS: Between 2006 and 2012, the Philippine National Influenza Centre detected HAdV in 1294 samples of patients with ILI. Serotype determination was done in select samples using microneutralization, polymerase chain reaction (PCR), and sequencing methods. RESULTS: A total of 8 serotypes were identified (HAdV 1-7 and 11), with HAdV-2 (27.8%), and HAdV-3 (27.8%) being the most prevalent. The majority of HAdV infections were found in children below 5 years of age (79.9%). CONCLUSIONS: The identification of HAdV circulating serotypes may serve as guide for designing disease intervention and control strategies and will provide important information regarding the contribution of this virus to respiratory infections, particularly in children, which remain a public health burden in the Philippines.
Incidence of lower respiratory tract infection and associated viruses in a birth cohort in the Philippines. International-journal Peer-reviewed

Kanako Otani, Mayuko Saito, Michiko Okamoto, Raita Tamaki, Mariko Saito-Obata, Taro Kamigaki, Irene C Lirio, Edelwisa Segubre-Mercado, Veronica Tallo, Socorro Lupisan, Hitoshi Oshitani

BMC infectious diseases　22　(1)　313-313　2022/03/30

DOI： 10.1186/s12879-022-07289-3 　

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BACKGROUND: Lower respiratory tract infection (LRTI) is an important cause of morbidity and mortality in infants and young children. However, the etiological role of viruses and the timing of developing LRTI are not well defined. METHODS: We analyzed the data of a prospective cohort study in the Philippines as a birth cohort. We detected LRTI among children who visited healthcare facilities with respiratory symptom, and collected nasopharyngeal swabs for virus detection. We analyzed the incidence rates (IRs) and cumulative proportion of LRTI and severe LRTI by age group and each virus detected. RESULTS: A total of 350 LRTI episodes were observed from 473 child-years yielded from 419 children. The IRs of LRTI were 70.8, 70.7, and 80.8 per 100 child-years for 0-5, 6-11, and 12-23 months of age, respectively. By 12 months of age, 45% of children developed LRTI at least once. Rhinovirus and respiratory syncytial virus were the most frequently detected viruses in all age groups. However, the IRs of influenza virus were low especially at 0-5 months of age. CONCLUSIONS: We identified various patterns of age-specific IRs of LRTI and severe LRTI for different viruses, which should be considered to establish more effective interventions including vaccinations.
Near-Complete Genome Sequencing of Influenza C Virus in the Philippines between 2014 and 2019. International-journal Peer-reviewed

Daisetsu Fujita, Clyde Dapat, Emmanuel Kagning Tsinda, Mayuko Saito, Michiko Okamoto, Mariko Saito-Obata, Beatriz P Quiambao, Socorro P Lupisan, Hitoshi Oshitani

Microbiology resource announcements　10　(49)　e0090021　2021/12/09

DOI： 10.1128/MRA.00900-21 　

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We report 19 nearly complete genome sequences of influenza C virus isolated from clinical samples recovered from children in the Philippines between 2014 and 2019.
Complete Genome Sequences of Enterovirus D68 Clade A and D Strains in the Philippines. International-journal Peer-reviewed

Michiko Okamoto, Masahiro Sakamoto, Clyde Dapat, Mayuko Saito, Mariko Saito-Obata, Raita Tamaki, Socorro P Lupisan, Beatriz P Quiambao, Hitoshi Oshitani

Microbiology resource announcements　10　(39)　e0070921　2021/09/30

DOI： 10.1128/MRA.00709-21 　

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Complete genome sequences were determined for 4 clade A and 12 clade D enterovirus D68 strains detected in nasopharyngeal swabs from children with acute respiratory illness in the Philippines. These sequence data will be useful for future epidemiological monitoring, including watching for viral evolution.
Global burden of acute lower respiratory infection associated with human parainfluenza virus in children younger than 5 years for 2018: a systematic review and meta-analysis. International-journal Peer-reviewed

Xin Wang, You Li, Maria Deloria-Knoll, Shabir A Madhi, Cheryl Cohen, Vina Lea Arguelles, Sudha Basnet, Quique Bassat, W Abdullah Brooks, Marcela Echavarria, Rodrigo A Fasce, Angela Gentile, Doli Goswami, Nusrat Homaira, Stephen R C Howie, Karen L Kotloff, Najwa Khuri-Bulos, Anand Krishnan, Marilla G Lucero, Socorro Lupisan, Maria Mathisen, Kenneth A McLean, Ainara Mira-Iglesias, Cinta Moraleda, Michiko Okamoto, Histoshi Oshitani, Katherine L O'Brien, Betty E Owor, Zeba A Rasmussen, Barbara A Rath, Vahid Salimi, Pongpun Sawatwong, J Anthony G Scott, Eric A F Simões, Viviana Sotomayor, Donald M Thea, Florette K Treurnicht, Lay-Myint Yoshida, Heather J Zar, Harry Campbell, Harish Nair

The Lancet. Global health　9　(8)　e1077-e1087　2021/08

DOI： 10.1016/S2214-109X(21)00218-7 　

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BACKGROUND: Human parainfluenza virus (hPIV) is a common virus in childhood acute lower respiratory infections (ALRI). However, no estimates have been made to quantify the global burden of hPIV in childhood ALRI. We aimed to estimate the global and regional hPIV-associated and hPIV-attributable ALRI incidence, hospital admissions, and mortality for children younger than 5 years and stratified by 0-5 months, 6-11 months, and 12-59 months of age. METHODS: We did a systematic review of hPIV-associated ALRI burden studies published between Jan 1, 1995, and Dec 31, 2020, found in MEDLINE, Embase, Global Health, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Global Health Library, three Chinese databases, and Google search, and also identified a further 41 high-quality unpublished studies through an international research network. We included studies reporting community incidence of ALRI with laboratory-confirmed hPIV; hospital admission rates of ALRI or ALRI with hypoxaemia in children with laboratory-confirmed hPIV; proportions of patients with ALRI admitted to hospital with laboratory-confirmed hPIV; or in-hospital case-fatality ratios (hCFRs) of ALRI with laboratory-confirmed hPIV. We used a modified Newcastle-Ottawa Scale to assess risk of bias. We analysed incidence, hospital admission rates, and hCFRs of hPIV-associated ALRI using a generalised linear mixed model. Adjustment was made to account for the non-detection of hPIV-4. We estimated hPIV-associated ALRI cases, hospital admissions, and in-hospital deaths using adjusted incidence, hospital admission rates, and hCFRs. We estimated the overall hPIV-associated ALRI mortality (both in-hospital and out-hospital mortality) on the basis of the number of in-hospital deaths and care-seeking for child pneumonia. We estimated hPIV-attributable ALRI burden by accounting for attributable fractions for hPIV in laboratory-confirmed hPIV cases and deaths. Sensitivity analyses were done to validate the estimates of overall hPIV-associated ALRI mortality and hPIV-attributable ALRI mortality. The systematic review protocol was registered on PROSPERO (CRD42019148570). FINDINGS: 203 studies were identified, including 162 hPIV-associated ALRI burden studies and a further 41 high-quality unpublished studies. Globally in 2018, an estimated 18·8 million (uncertainty range 12·8-28·9) ALRI cases, 725 000 (433 000-1 260 000) ALRI hospital admissions, and 34 400 (16 400-73 800) ALRI deaths were attributable to hPIVs among children younger than 5 years. The age-stratified and region-stratified analyses suggested that about 61% (35% for infants aged 0-5 months and 26% for 6-11 months) of the hospital admissions and 66% (42% for infants aged 0-5 months and 24% for 6-11 months) of the in-hospital deaths were in infants, and 70% of the in-hospital deaths were in low-income and lower-middle-income countries. Between 73% and 100% (varying by outcome) of the data had a low risk in study design; the proportion was 46-65% for the adjustment for health-care use, 59-77% for patient groups excluded, 54-93% for case definition, 42-93% for sampling strategy, and 67-77% for test methods. Heterogeneity in estimates was found between studies for each outcome. INTERPRETATION: We report the first global burden estimates of hPIV-associated and hPIV-attributable ALRI in young children. Globally, approximately 13% of ALRI cases, 4-14% of ALRI hospital admissions, and 4% of childhood ALRI mortality were attributable to hPIV. These numbers indicate a potentially notable burden of hPIV in ALRI morbidity and mortality in young children. These estimates should encourage and inform investment to accelerate the development of targeted interventions. FUNDING: Bill & Melinda Gates Foundation.
Risk of Transmission and Viral Shedding from the Time of Infection for Respiratory Syncytial Virus in Households. International-journal Peer-reviewed

Hirono Otomaru, Johanna Beulah T Sornillo, Taro Kamigaki, Samantha Louise P Bado, Michiko Okamoto, Mariko Saito-Obata, Marianette T Inobaya, Edelwisa Segubre-Mercado, Portia P Alday, Mayuko Saito, Veronica L Tallo, Beatriz P Quiambao, Hitoshi Oshitani, Alex R Cook

American journal of epidemiology　190　(12)　2536-2543　2021/07/03

DOI： 10.1093/aje/kwab181 　

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Respiratory Syncytial Virus (RSV) is a leading cause of lower respiratory tract infection worldwide. The report of temporal changes in the risk of transmission among close contacts has been scarce. This study aims to examine an association between the viral load trajectory and transmission risk to develop a better control strategy for the disease spread. We conducted a household-based prospective cohort study in Biliran Province, the Philippines, and enrolled 451 participants for observing the development of acute respiratory infection. Including the cases found at the health care facility, we analyzed the data of viral loads with symptom records obtained from 172 followed-up participants whose household member was RSV positive with a rapid test during an RSV outbreak in 2018-2019. We developed a model estimating a temporal change of the viral shedding from the infection and evaluated transmission dynamics. We revealed that most transmission events occurred within approximately 7 days from the household exposure, including potential pre-symptomatic transmissions. The inferred risk of infection among those younger than 5 years old was 3.5 times higher than that of those older than 5 years. This finding suggested that the initial week after the household exposure is particularly important for preventing RSV spread.
Inactivation of SARS-CoV-2 by Catechins from Green Tea. Peer-reviewed

Hidekazu Nishimura, Michiko Okamoto, Isolde Dapat, Masanori Katumi, Hitoshi Oshitani

Japanese journal of infectious diseases　2021/01/29

DOI： 10.7883/yoken.JJID.2020.902 　

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Green tea extracts effectively inactivated SARS-CoV-2 in vitro in a dose-dependent manner. Serially 10-fold diluted solutions of catechin mixture reagent from green tea were mixed with the viral culture fluid at a volume ratio of nine to one, respectively, and kept at room temperature for 5 min. The solution of 10 mg/mL catechin reagent reduced the viral titer by 4.2 log and 1.0 mg/mL solution reduced only by one log. Pre-infection treatment of the cells with the reagent alone did not affect the viral growth. In addition, cells treated with only the reagent was assayed for host-cell viability using the WST-8 system and almost no host-cell damage by the treatment was observed. These findings suggested that the direct treatment of virus with the reagent before inoculation decreased the viral activity and that catechins might have a potential to suppress the SARS-CoV-2 infection.
Gene signature of children with severe respiratory syncytial virus infection. International-journal Peer-reviewed

Clyde Dapat, Satoru Kumaki, Hiroki Sakurai, Hidekazu Nishimura, Hannah Karen Mina Labayo, Michiko Okamoto, Mayuko Saito, Hitoshi Oshitani

Pediatric research　2021/01/28

DOI： 10.1038/s41390-020-01347-9 　

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BACKGROUND: The limited treatment options for children with severe respiratory syncytial virus (RSV) infection highlights the need for a comprehensive understanding of the host cellular response during infection. We aimed to identify host genes that are associated with severe RSV disease and to identify drugs that can be repurposed for the treatment of severe RSV infection. METHODS: We examined clinical data and blood samples from 37 hospitalized children (29 mild and 8 severe) with RSV infection. We tested RNA from blood samples using next-generation sequencing to profile global mRNA expression and identify cellular processes. RESULTS: Retractions, decreased breath sounds, and tachypnea were associated with disease severity. We observed upregulation of genes related to neutrophil, inflammatory response, blood coagulation, and downregulation of genes related to T cell response in children with severe RSV. Using network-based approach, 43 drugs were identified that are predicted to interact with the gene products of these differentially expressed genes. CONCLUSIONS: These results suggest that the changes in the expression pattern in the innate and adaptive immune responses may be associated with RSV clinical severity. Compounds that target these cellular processes can be repositioned as candidate drugs in the treatment of severe RSV. IMPACT: Neutrophil, inflammation, and blood coagulation genes are upregulated in children with severe RSV infection. Expression of T cell response genes are suppressed in cases of severe RSV. Genes identified in this study can contribute in understanding the pathogenesis of RSV disease severity. Drugs that target cellular processes associated with severe RSV can be repositioned as potential therapeutic options.
Epidemiological and clinical characteristics of children with acute respiratory viral infections in the Philippines: a prospective cohort study. International-journal Peer-reviewed

Yuki Furuse, Raita Tamaki, Akira Suzuki, Taro Kamigaki, Michiko Okamoto, Mariko Saito-Obata, Emiko Nakagawa, Mayuko Saito, Edelwisa Segubre-Mercado, Veronica Tallo, Socorro Lupisan, Hitoshi Oshitani

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases　27　(7)　1037.e9-1037.e14　2020/09/17

DOI： 10.1016/j.cmi.2020.09.017 　

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OBJECTIVES: Viral acute respiratory infection (ARI) remains a major global health problem, especially among children in low- and middle-income countries. The study was conducted to reveal aetiological significance of respiratory viruses among both non-hospitalized and hospitalized children. METHODS: A cohort study of children with ARI at the household, primary healthcare facility, and hospital levels was conducted alongside a hospital-based study including non-cohort children from 2014 to 2016 in the Philippines. The ARI cases were recorded at households and healthcare facilities, and a clinical investigation was performed. Nasopharyngeal swabs were collected from the symptomatic children and tested for respiratory viruses via polymerase chain reaction. Then, the association between healthcare facility utilization and viral detection was investigated. RESULTS: Overall, 18,514 ARI cases were enrolled in the cohort study, and samples were collected from 4735 of these cases. The hospital-based study detected 648 ARI cases, all of which were sampled. Rhinovirus (22.2%; 1052/4735) was most frequently detected followed by respiratory syncytial virus (12.0%; 566/4735). Enterovirus (adjusted odds ratio, 1.8; 95% confidence interval, 1.1-2.8), human metapneumovirus (2.1, 1.4-3.2), rhinovirus (2.1, 1.8-2.6), and respiratory syncytial virus (1.6, 1.2-1.9) were significantly more prevalent in the ARI cases at healthcare facilities than in those in households. Of all ARI cases, 0.6% required hospitalization while 1.8% were hospitalized among the respiratory syncytial virus-positive cases (3.8, 3.0-4.9). CONCLUSIONS: We determined the prevalence of respiratory viruses among children with ARIs at the household, primary healthcare facility, and hospital levels and the association with clinical characteristics. In particular, we discovered a significant disease burden and impact of respiratory syncytial virus infections as well as a considerable aetiological implication of rhinovirus infections.
Receptor-Binding Assays of Enterovirus D68. International-journal

Tadatsugu Imamura, Michiko Okamoto, Hitoshi Oshitani

Methods in molecular biology (Clifton, N.J.)　2132　629-639　2020

DOI： 10.1007/978-1-0716-0430-4_54 　

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Human enterovirus D68 (EV-D68) is a causative agent for acute respiratory infections and potentially central nervous system illnesses with increasing epidemiological significance. Recent studies have highlighted the role of sialic acids as a functional receptor for EV-D68 in vitro. However, further investigations are required to reveal its significance in actual infections in human.
Fluctuations in antibody titers against enterovirus D68 in pediatric sera collected in a community before, during, and after a possible outbreak. Peer-reviewed

Kadji FMN, Nishimura H, Okamoto M, Sato K, Ohmiya S, Ito H, Suzuki A, Nagai Y, Oshitani H

Japanese journal of infectious diseases　73　(1)　55-57　2019/08

DOI： 10.7883/yoken.JJID.2019.056 　

ISSN： 1344-6304

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We previously reported a hospital-based epidemiological study on enterovirus (EV)-D68 infection among children during the autumn of 2015, which indirectly inferred an outbreak in Sendai, Japan. In this study, stocked sera of children (aged 0-6 years; without symptoms of infectious diseases) in the Sendai community collected during 4 periods (1 year before, 6 months before, immediately after, and 1 year after the possible outbreak period) were analyzed using the neutralization antibody titer assay to determine community children's immunity levels against EV-D68 infection. The immunity levels were confirmed to have increased during the possible outbreak period and to have gradually waned over 1 year without another outbreak. These results provide background information supporting the results of our previous hospital-based surveillance study.
Evolutionary and Functional Diversity of the 5' Untranslated Region of Enterovirus D68: Increased Activity of the Internal Ribosome Entry Site of Viral Strains during the 2010s. International-journal Peer-reviewed

Yuki Furuse, Natthawan Chaimongkol, Michiko Okamoto, Hitoshi Oshitani

Viruses　11　(7)　2019/07/08

DOI： 10.3390/v11070626 　

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The 5' untranslated region (UTR) of the RNA genomes of enteroviruses possesses an internal ribosome entry site (IRES) that directs translation of the mRNA by binding to ribosomes. Infection with enterovirus D68 causes respiratory symptoms and is sometimes associated with neurological disorders. The number of reports of the viral infection and neurological disorders has increased in 2010s, although the reason behind this phenomenon remains unelucidated. In this study, we investigated the evolutionary and functional diversity of the 5' UTR of recently circulating strains of the virus. Genomic sequences of 374 viral strains were acquired and subjected to phylogenetic analysis. The IRES activity of the viruses was measured using a luciferase reporter assay. We found a highly conserved sequence in the 5' UTR and also identified the location of variable sites in the predicted RNA secondary structure. IRES activities differed among the strains in some cell lines, including neuronal and respiratory cells, and were especially high in strains of a major lineage from the recent surge. The effect of mutations in the 5' UTR should be studied further in the future for better understanding of viral pathogenesis.
Age-specific incidence rates and risk factors for respiratory syncytial virus-associated lower respiratory tract illness in cohort children under 5 years old in the Philippines. International-journal Peer-reviewed

Fumihiko Ueno, Raita Tamaki, Mayuko Saito, Michiko Okamoto, Mariko Saito-Obata, Taro Kamigaki, Akira Suzuki, Edelwisa Segubre-Mercado, Hananiah D Aloyon, Veronica Tallo, Socorro P Lupisan, Hitoshi Oshitani

Influenza and other respiratory viruses　13　(4)　339-353　2019/07

DOI： 10.1111/irv.12639 　

ISSN： 1750-2640

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BACKGROUND: Respiratory syncytial virus (RSV) is one of the main viral causes of lower respiratory tract illness (LRTI), especially in young children. RSV vaccines, including maternal and infant vaccines, are under development; however, more epidemiological studies are needed to develop effective vaccination strategies. OBJECTIVES: To estimate detailed age-specific incidence rates and severity of RSV-associated LRTI (RSV-LRTI) using data from a community-based prospective cohort study in the Philippines. PATIENTS/METHODS: Cohort children who visited health facilities due to acute respiratory symptoms were identified, and nasopharyngeal swabs were collected to detect RSV. The severity of RSV-LRTI was assessed using the severity definition proposed by the World Health Organization. Risk factors for developing RSV-LRTI and contribution of SpO2 measurement were also evaluated. RESULTS: A total of 395 RSV episodes which occurred in children aged 2-59 months were categorised as 183 RSV-LRTI, 72 as severe RSV-LRTI and 29 as very severe RSV-LRTI. Children aged 3-5 months had the highest incidence rate of RSV-LRTI, at 207.4 per 1000 child-years (95% CI: 149.0-279.5). Younger age group, place of living and low educational level of caregivers were associated with developing RSV-LRTI. Clinical manifestations had low levels of agreement with hypoxaemia as measured by pulse oximeter. CONCLUSION: The highest burden of RSV was observed in young infants aged 3-5 months, whereas the burden was also high in those aged 12-20 months. Future vaccination strategies should consider the protection of older children, especially those aged one year, as well as young infants.
Aetiology and risks factors associated with the fatal outcomes of childhood pneumonia among hospitalised children in the Philippines from 2008 to 2016: a case series study. International-journal Peer-reviewed

Bindongo Price Polycarpe Dembele, Taro Kamigaki, Clyde Dapat, Raita Tamaki, Mariko Saito, Mayuko Saito, Michiko Okamoto, Mary Ann U Igoy, Edelwisa Segubre Mercado, Melisa Mondoy, Veronica L Tallo, Socorro P Lupisan, Shinichi Egawa, Hitoshi Oshitani

BMJ open　9　(3)　e026895　2019/03/30

DOI： 10.1136/bmjopen-2018-026895 　

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OBJECTIVE: Pneumonia remains the leading cause of hospitalisations and deaths among children aged <5 years. Diverse respiratory pathogens cause acute respiratory infections, including pneumonia. Here, we analysed viral and bacterial pathogens and risk factors associated with death of hospitalised children. DESIGN: A 9-year case series study. SETTING: Two secondary-care hospitals, one tertiary-care hospital and one research centre in the Philippines. PARTICIPANTS: 5054 children aged <5 years hospitalised with severe pneumonia. METHODS: Nasopharyngeal swabs for virus identification, and venous blood samples for bacterial culture were collected. Demographic, clinical data and laboratory findings were collected at admission time. Logistic regression analyses were performed to identify the factors associated with death. RESULTS: Of the enrolled patients, 57% (2876/5054) were males. The case fatality rate was 4.7% (238/5054), showing a decreasing trend during the study period (p<0.001). 55.0% of the patients who died were either moderately or severely underweight. Viruses were detected in 61.0% of the patients, with respiratory syncytial virus (27.0%) and rhinovirus (23.0%) being the most commonly detected viruses. In children aged 2-59 months, the risk factors significantly associated with death included age of 2-5 months, sensorial changes, severe malnutrition, grunting, central cyanosis, decreased breath sounds, tachypnoea, fever (≥38.5°C), saturation of peripheral oxygen <90%, infiltration, consolidation and pleural effusion on chest radiograph.Among the pathogens, adenovirus type 7, seasonal influenza A (H1N1) and positive blood culture for bacteria were significantly associated with death. Similar patterns were observed between the death cases and the aforementioned factors in children aged <2 months. CONCLUSION: Malnutrition was the most common factor associated with death and addressing this issue may decrease the case fatality rate. In addition, chest radiographic examination and oxygen saturation measurement should be promoted in all hospitalised patients with pneumonia as well as bacteria detection to identify patients who are at risk of death.
Transmission of Respiratory Syncytial Virus Among Children Under 5 Years in Households of Rural Communities, the Philippines. Peer-reviewed

Otomaru H, Kamigaki T, Tamaki R, Okamoto M, Alday PP, Tan AG, Manalo JI, Segubre-Mercado E, Inobaya MT, Tallo V, Lupisan S, Oshitani H

Open forum infectious diseases　6　(3)　ofz045　2019/03
Publisher: Oxford University Press (OUP)
DOI： 10.1093/ofid/ofz045 　

eISSN： 2328-8957

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Abstract Background To develop a more effective vaccination strategy for reducing the impact of respiratory syncytial virus (RSV) infection, especially in young infants (&lt;6 months old), it is necessary to understand the transmission dynamics of RSV. Methods We conducted a community-based prospective cohort study from 2014 to 2016 in Biliran Province, the Philippines, on children &lt;5 years old. We collected nasopharyngeal swabs from symptomatic children with acute respiratory infection (ARI) during household visits and at health facilities. In households (n = 181) with RSV-positive ARI cases (RSV-ARI), we also identified ARI episodes among other children &lt;5 years old in the same household. In addition, we determined the serial interval to estimate the basic reproduction number (R0), the average number of secondary cases generated by a single primary case. Results In the 181 households analyzed, we found 212 RSV-ARI in 152 households with a single case and 29 households with multiple cases, which included 29 1st RSV-ARI and 31 2nd RSV-ARI. We also found possible index cases among children &lt;5 years old in the same household for 29.0% (18 of 62) of young infants with RSV-ARI. The estimated mean serial interval was 3.2 days, and R0 was estimated to be 0.92–1.33 for RSV-A and 1.04–1.76 for RSV-B, which varied between different times (2014 and 2015) and places. Conclusions Young infants are likely to acquire RSV infection from older children in the same household. Therefore, vaccination targeting older children might protect infants from RSV infection.
Association Between Preceding Viral Respiratory Infection and Subsequent Respiratory Illnesses Among Children: A Prospective Cohort Study in the Philippines. International-journal Peer-reviewed

Yuki Furuse, Raita Tamaki, Michiko Okamoto, Mariko Saito-Obata, Akira Suzuki, Mayuko Saito, Tadatsugu Imamura, Irona Khandaker, Isolde Dapat, Fumihiko Ueno, Portia Parian Alday, Alvin Gue Tan, Marianette Tawat Inobaya, Edelwisa Segubre-Mercado, Veronica Tallo, Socorro Lupisan, Hitoshi Oshitani

The Journal of infectious diseases　219　(2)　197-205　2019/01/07

DOI： 10.1093/infdis/jiy515 　

ISSN： 0022-1899

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Background: Acute respiratory infection (ARI) is of great concern in public health. It remains unclear whether viral infections can affect the host's susceptibility to subsequent ARIs. Methods: A prospective cohort study on ARIs of children below 5 years old was conducted in the Philippines from 2014 to 2016. The respiratory symptoms were recorded daily, and nasopharyngeal swabs were collected at both household and health facilities. The specimens were tested for respiratory viruses. We then determined whether viral etiology was associated with the severity of the present ARI and whether previous viral infections was associated with subsequent ARIs. Results: A total of 3851 children and 16337 ARI episodes were enrolled and recorded, respectively. Samples were collected from 24% of all ARI episodes; collection rate at the healthcare facilities was 95%. Enterovirus D68, rhinovirus species C, and respiratory syncytial virus were significantly associated with severe ARIs. The risk for subsequent ARIs was significantly enhanced after infections with adenovirus, influenza A virus, parainfluenza virus type 4, and rhinovirus species C. Conclusions: This study revealed that viral etiology plays a significant role in the severity of the present ARI and that viral infection affects the host's susceptibility to subsequent ARIs.
Complete Genome Sequences of 12 Human Respiratory Syncytial Virus (Human Orthopneumovirus) Strains Detected in Children with Repeated Subgroup B Infections in the Philippines. International-journal Peer-reviewed

Michiko Okamoto, Masahiro Sakamoto, Clyde Dapat, Mayuko Saito, Mariko Saito-Obata, Raita Tamaki, Socorro P Lupisan, Hitoshi Oshitani

Microbiology resource announcements　7　(22)　2018/12

DOI： 10.1128/MRA.01017-18 　

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Complete genome sequences were determined for 12 human respiratory syncytial virus strains collected from nasopharyngeal samples obtained from children with repeated subgroup B infections. Eight common amino acid polymorphisms in the G, F, and L proteins were identified between the viruses detected in initial and subsequent infections.
Etiology and epidemiology of community-acquired pneumonia in adults requiring hospital admission: a prospective study in rural Central Philippines. International-journal Peer-reviewed

Lupisan S, Suzuki A, Macalalad N, Egos R, Sombrero L, Okamoto M, Dapat C, Mondoy M, Galang H, Zeta VFF, de la Pena F, Romano V, Olveda R, Oshitani H

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases　80　46-53　2018/12

DOI： 10.1016/j.ijid.2018.12.005 　

ISSN： 1201-9712

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BACKGROUND: Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality among adults worldwide. However, the distribution of the etiology of CAP varies from one country to another, with limited data from rural areas. METHODS: A prospective hospital-based study on adult CAP was conducted in Leyte, Central Philippines from May 2010 to May 2012. Blood, sputum, and nasopharyngeal samples obtained from patients were used to identify pathogens using standard microbiological culture methods and PCR. RESULTS: Of the 535 patients enrolled, 38% were younger than 50 years old. More than half of the patients had an underlying disease, including pulmonary tuberculosis (22%). The detection rate was higher for bacteria (40%) than viruses (13%). Haemophilus influenzae (12%) was the most commonly detected bacterium and influenza virus (5%) was the most commonly detected virus. The proportion of CAP patients with Mycobacterium tuberculosis infection was higher in the younger age group than in the older age group. Among CAP patients, 14% died during hospitalization, and drowsiness on admission and SpO2 <90% were independent risk factors for mortality. CONCLUSIONS: Bacterial infections contribute substantially to the number of hospitalizations among CAP patients in rural Philippines. This study also highlights the importance of treatment of tuberculosis in reducing the burden of adult CAP in the country.
Molecular Characterization of Respiratory Syncytial Virus in Children With Repeated Infections With Subgroup B in the Philippines. International-journal Peer-reviewed

Michiko Okamoto, Clyde P Dapat, Ann Marie D Sandagon, Leilanie P Batangan-Nacion, Irene C Lirio, Raita Tamaki, Mayuko Saito, Mariko Saito-Obata, Socorro P Lupisan, Hitoshi Oshitani

The Journal of infectious diseases　218　(7)　1045-1053　2018/08/24

DOI： 10.1093/infdis/jiy256 　

ISSN： 0022-1899

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Background: Human respiratory syncytial virus (RSV) is the leading cause of severe acute respiratory infection in infants and young children, which is characterized by repeated infections. However, the role of amino acid substitutions in repeated infections remains unclear. Hence, this study aimed to elucidate the genetic characteristics of RSV in children with repeated infections using molecular analyses of F and G genes. Methods: We conducted a cohort study of children younger than 5 years in the Philippines. We collected nasopharyngeal swabs from children with acute respiratory symptoms and compared F and G sequences between initial and subsequent RSV infections. Results: We examined 1802 children from May 2014 to January 2016 and collected 3471 samples. Repeated infections were observed in 25 children, including 4 with homologous RSV-B reinfections. Viruses from the 4 pairs of homologous reinfections had amino acid substitutions in the G protein mostly at O-glycosylation sites, whereas changes in the F protein were identified at antigenic sites V (L173S) and θ (Q209K), considered essential epitopes for the prefusion conformation of the F protein. Conclusions: Amino acid substitutions in G and F proteins of RSV-B might have led to antigenic changes, potentially contributing to homologous reinfections observed in this study.
Comprehensive etiological and epidemiological study on acute respiratory infections in children: Providing evidence for the prevention and control of childhood plneumonia in the Philippines

Raita Tamaki, Raita Tamaki, Veronica L. Tallo, Alvin G. Tan, Mark Donal, C. Reñosa, Portia P. Alday, Jhoys M. Landicho, Marianette T. Inobaya, Mayuko Saito, Taro Kamigaki, Michiko Okamoto, Mariko Saito, Clyde Dapat, Bindongo, P.P. Dembele, Mary Lorraine, S. Mationg, Melisa U. Mondoy, Socorro P. Lupisan, Hitoshi Oshitani

Journal of Disaster Research　13　(4)　740-750　2018/08/01
Publisher: Fuji Technology Press Ltd.
DOI： 10.20965/jdr.2018.p0740 　

ISSN： 1881-2473

eISSN： 1883-8030
Clinical Features of Human Metapneumovirus Pneumonia in Non-Immunocompromised Patients: An Investigation of Three Long-Term Care Facility Outbreaks. Peer-reviewed

Karimata Y, Kinjo T, Parrott G, Uehara A, Nabeya D, Haranaga S, Higa F, Tateyama M, Miyagawa K, Kishaba T, Otani K, Okamoto M, Nishimura H, Fujita J

The Journal of infectious diseases　218　(6)　868-875　2018/08
Publisher: Oxford University Press (OUP)
DOI： 10.1093/infdis/jiy261 　

ISSN： 0022-1899

eISSN： 1537-6613
Concurrent Community Transmission of Enterovirus D68 With Human Rhinoviruses and Respiratory Syncytial Virus Among Children in Sendai, Japan. Peer-reviewed

Metoki T, Okamoto M, Suzuki A, Kitaoka S, Miyabayashi H, Rokugo Y, Onuma R, Noguchi R, Sato T, Watanabe Y, Ohmiya S, Sato K, Nishimura H, Oshitani H, Kumaki S

The Pediatric infectious disease journal　37　(5)　394-400　2018/05

DOI： 10.1097/INF.0000000000001768 　

ISSN： 0891-3668
Complete Genome Sequences of 13 Human Respiratory Syncytial Virus Subgroup A Strains of Genotypes NA1 and ON1 Isolated in the Philippines. International-journal Peer-reviewed

Rungnapa Malasao, Yuki Furuse, Michiko Okamoto, Clyde Dapat, Mayuko Saito, Mariko Saito-Obata, Raita Tamaki, Edelwisa Segubre-Mercado, Socorro Lupisan, Hitoshi Oshitani

Genome announcements　6　(10)　2018/03/08

DOI： 10.1128/genomeA.00151-18 　

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Complete genome sequences of 13 human respiratory syncytial virus strains were determined from samples obtained from children hospitalized in the Philippines between 2012 and 2013 because of acute respiratory infection. We identified amino acid polymorphisms between the NA1 and ON1 genotypes in the P, G, F, and L proteins.
フィリピンの小児呼吸器疾患症例におけるエンテロウイルスD68の疫学的・臨床的解析 Peer-reviewed

齊藤麻理子[小畑], 岡本道子, 齊藤繭子, Chaimongkol Natthawan, 玉記雷太, Lupisan Socorro, 押谷仁

グローバルヘルス合同大会プログラム・抄録集　2017　314-314　2017/11
Publisher: グローバルヘルス合同大会事務局
Efficient isolation of human metapneumovirus using MNT-1, a human malignant melanoma cell line with early and distinct cytopathic effects Peer-reviewed

Ko Sato, Oshi Watanabe, Suguru Ohmiya, Fumiko Chiba, Akira Suzuki, Michiko Okamoto, Jiang Younghuang, Akihiro Hata, Hiroyuki Nonaka, Setsuko Kitaoka, Yukio Nagai, Kazuhisa Kawamura, Masahiro Hayashi, Satoru Kumaki, Tamio Suzuki, Kazuyoshi Kawakami, Hidekazu Nishimura

MICROBIOLOGY AND IMMUNOLOGY　61　(11)　497-506　2017/11

DOI： 10.1111/1348-0421.12542 　

ISSN： 0385-5600

eISSN： 1348-0421
First detection of DS-1-like G1P[8] human rotavirus strains from children with diarrhoea in the Philippines

D. Yamamoto, D. Yamamoto, A. Tandoc, E. Mercado, F. Quicho, S. Lupisan, M. Obata-Saito, M. Obata-Saito, M. Okamoto, A. Suzuki, R. Tamaki, L. Sombrero, R. Olveda, H. Oshitani

New Microbes and New Infections　18　54-57　2017/07/01
Publisher: Elsevier BV
DOI： 10.1016/j.nmni.2017.04.001 　

ISSN： 2052-2975
First report of severe acute otitis media caused by Campylobacter rectus and review of the literature Peer-reviewed

Risako Kakuta, Hiroshi Hidaka, Hisakazu Yano, Michiko Okamoto, Daiki Ozawa, Shiro Endo, Mitsuo Kaku, Yukio Katori

JOURNAL OF INFECTION AND CHEMOTHERAPY　22　(12)　800-803　2016/12

DOI： 10.1016/j.jiac.2016.06.001 　

ISSN： 1341-321X

eISSN： 1437-7780
Laboratory Diagnosis for Outbreak-Prone Infectious Diseases after Typhoon Yolanda (Haiyan), Philippines. International-journal Peer-reviewed

Mariko Saito-Obata, Mayuko Saito, Titus C Tan, Inez Andrea P Medado, Clyde Dapat, Michiko Okamoto, Raita Tamaki, Rowena C Capistrano, Edelwisa Segubre-Mercado, Socorro P Lupisan, Hitoshi Oshitani

PLoS currents　8　2016/10/21

DOI： 10.1371/currents.dis.9c3cb7b01ec2d04eef2406dbe03d253d 　

eISSN： 2157-3999

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INTRODUCTION: Typhoon Yolanda (Haiyan) hit the central part of the Philippines on November 8, 2013. To identify possible outbreaks of communicable diseases after the typhoon, nasopharyngeal swabs, stool and blood samples were collected from patients who visited the Eastern Visayas Regional Medical Center due to acute respiratory infection (ARI), acute gastroenteritis (AGE) or other febrile illness (OFI) including suspected dengue fever, between November 28, 2013 and February 5, 2014. Methods: Samples were tested on-site for selected pathogens using rapid diagnostic tests. Confirmation and further analysis were conducted at the Research Institute for Tropical Medicine (RITM) in Manila using polymerase chain reaction (PCR) and sequencing. Residues of the rapid diagnostic tests and samples collected in the filter papers (FTATM card) were transported to Manila under suboptimal conditions. PCR results were compared between the kit residues and the filter papers. Results: A total of 185 samples were collected. Of these, 128 cases were ARI, 17 cases were AGE and 40 cases were OFI. For nasopharyngeal swab samples, detection rates for enterovirus and rhinovirus residues were higher than the filter papers. For stool samples, rotavirus positive rate for the filter paper was higher than the kit residues. We also managed to obtain the sequence data from some of the kit residues and filter papers. Discussion: Our results confirmed the importance of PCR for the laboratory diagnosis of infectious diseases in post-disaster situations when diagnostic options are limited.
Etiological Role and Repeated Infections of Sapovirus among Children Aged Less than 2 Years in a Cohort Study in a Peri-urban Community of Peru Peer-reviewed

Xiaofang Liu, Helena Jahuira, Robert H. Gilman, Alicia Alva, Lilia Cabrera, Michiko Okamoto, Hang Xu, Henry J. Windle, Dermot Kelleher, Marco Varela, Manuela Verastegui, Maritza Calderon, Gerardo Sanchez, Vanessa Sarabia, Sarah B. Ballard, Caryn Bern, Holger Mayta, Jean E. Crabtree, Vitaliano Cama, Mayuko Saito, Hitoshi Oshitani

JOURNAL OF CLINICAL MICROBIOLOGY　54　(6)　1598-1604　2016/06

DOI： 10.1128/JCM.03133-15 　

ISSN： 0095-1137

eISSN： 1098-660X
Association of RSV-A ON1 genotype with Increased Pediatric Acute Lower Respiratory Tract Infection in Vietnam Peer-reviewed

Keisuke Yoshihara, Minh Nhat Le, Michiko Okamoto, Anita Carolle Akpeedje Wadagni, Hien Anh Nguyen, Michiko Toizumi, Enga Pham, Motoi Suzuki, Ai Thi Thuy Nguyen, Hitoshi Oshitani, Koya Ariyoshi, Hiroyuki Moriuchi, Masahiro Hashizume, Duc Anh Dang, Lay-Myint Yoshida

SCIENTIFIC REPORTS　6　27856　2016/06

DOI： 10.1038/srep27856 　

ISSN： 2045-2322
Differences in viral load among human respiratory syncytial virus genotypes in hospitalized children with severe acute respiratory infections in the Philippines. Peer-reviewed

Kadji FM, Okamoto M, Furuse Y, Tamaki R, Suzuki A, Lirio I, Dapat C, Malasao R, Saito M, Pedrera-Rico GA, Tallo V, Lupisan S, Saito M, Oshitani H

Virology journal　13　113　2016/06

DOI： 10.1186/s12985-016-0565-8 　
Local persistence and global dissemination play a significant role in the circulation of influenza B viruses in Leyte Island, Philippines. International-journal Peer-reviewed

Yuki Furuse, Takashi Odagiri, Raita Tamaki, Taro Kamigaki, Hirono Otomaru, Jamie Opinion, Arlene Santo, Donna Dolina-Lacaba, Edgard Daya, Michiko Okamoto, Mariko Saito-Obata, Marianette Inobaya, Alvin Tan, Veronica Tallo, Socorro Lupisan, Akira Suzuki, Hitoshi Oshitani

Virology　492　21-4　2016/05

DOI： 10.1016/j.virol.2016.02.001 　

ISSN： 0042-6822

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The local and global transmission dynamics of influenza B virus is not completely understood mainly because of limited epidemiological and sequence data for influenza B virus. Here we report epidemiological and molecular characteristics of influenza B viruses from 2010 to 2013 in Leyte Island, Philippines. Phylogenetic analyses showed global dissemination of the virus among both neighboring and distant areas. The analyses also suggest that southeast Asia is not a distributor of influenza B virus and can introduce the virus from other areas. Furthermore, we found evidence on the local persistence of the virus over years in the Philippines. Taken together, both local persistence and global dissemination play a significant role in the circulation of influenza B virus.
Conservation of nucleotide sequences for molecular diagnosis of Middle East respiratory syndrome coronavirus, 2015. International-journal Peer-reviewed

Yuki Furuse, Michiko Okamoto, Hitoshi Oshitani

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases　40　25-7　2015/11

DOI： 10.1016/j.ijid.2015.09.018 　

ISSN： 1201-9712

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Infection due to the Middle East respiratory syndrome coronavirus (MERS-CoV) is widespread. The present study was performed to assess the protocols used for the molecular diagnosis of MERS-CoV by analyzing the nucleotide sequences of viruses detected between 2012 and 2015, including sequences from the large outbreak in eastern Asia in 2015. Although the diagnostic protocols were established only 2 years ago, mismatches between the sequences of primers/probes and viruses were found for several of the assays. Such mismatches could lead to a lower sensitivity of the assay, thereby leading to false-negative diagnosis. A slight modification in the primer design is suggested. Protocols for the molecular diagnosis of viral infections should be reviewed regularly after they are established, particularly for viruses that pose a great threat to public health such as MERS-CoV.
Molecular Characterization of Human Respiratory Syncytial Virus in the Philippines, 2012-2013 Peer-reviewed

Rungnapa Malasao, Michiko Okamoto, Natthawan Chaimongkol, Tadatsugu Imamura, Kentaro Tohma, Isolde Dapat, Clyde Dapat, Akira Suzuki, Mayuko Saito, Mariko Saito, Raita Tamaki, Gay Anne Granada Pedrera-Rico, Rapunzel Aniceto, Reynaldo Frederick Negosa Quicho, Edelwisa Segubre-Mercado, Socorro Lupisan, Hitoshi Oshitani

PLOS ONE　10　(11)　e0142192　2015/11

DOI： 10.1371/journal.pone.0142192 　

ISSN： 1932-6203
Molecular detection and characterization of sapovirus in hospitalized children with acute gastroenteritis in the Philippines Peer-reviewed

Xiaofang Liu, Dai Yamamoto, Mariko Saito, Toshifumi Imagawa, Adrianne Ablola, Amado O. Tandoc, Edelwisa Segubre-Mercado, Socorro P. Lupisan, Michiko Okamoto, Yuki Furuse, Mayuko Saito, Hitoshi Oshitani

JOURNAL OF CLINICAL VIROLOGY　68　83-88　2015/07

DOI： 10.1016/j.jcv.2015.05.001 　

ISSN： 1386-6532

eISSN： 1873-5967
Genetic characterization of measles virus in the Philippines, 2008-2011. International-journal Peer-reviewed

Rex Centeno, Naoko Fuji, Michiko Okamoto, Clyde Dapat, Mariko Saito, Amado Tandoc, Socorro Lupisan, Hitoshi Oshitani

BMC research notes　8　211-211　2015/06/03

DOI： 10.1186/s13104-015-1201-1 　

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BACKGROUND: Large outbreaks of measles occurred in the Philippines in 2010 and 2011. Genetic analysis was performed to identify the genotype of measles virus (MeV) that was responsible for the large outbreaks. METHODS: A total of 114 representative MeVs that were detected in the Philippines from 2008 to 2011 were analyzed by sequencing the C-terminal region of nucleocapsid (N) gene and partial hemagglutinin (H) gene and by inferring the phylogenetic trees. RESULTS: Genetic analysis showed that genotype D9 was the predominant circulating strain during the 4-year study period. Genotype D9 was detected in 23 samples (92%) by N gene sequencing and 93 samples (94%) by H gene analysis. Sporadic cases of genotype G3 MeV were identified in 2 samples (8%) by N gene sequencing and 6 samples (6%) by H gene analysis. Genotype G3 MeV was detected mainly in Panay Island in 2009 and 2010. Molecular clock analysis of N gene showed that the recent genotype D9 viruses that caused the big outbreaks in 2010 and 2011 diverged from a common ancestor in 2005 in one of the neighboring Southeast Asian countries, where D9 was endemic. These big outbreaks of measles resulted in a spillover and were associated with genotype D9 MeV importation to Japan and the USA. CONCLUSION: Genotype D9 MeV became endemic and caused two big outbreaks in the Philippines in 2010 and 2011. Genotype G3 MeV was detected sporadically with limited geographic distribution. This study highlights the importance of genetic analysis not only in helping with the assessment of measles elimination program in the country but also in elucidating the transmission dynamics of measles virus.
Influenza and Other Respiratory Viruses Detected by Influenza-Like Illness Surveillance in Leyte Island, the Philippines, 2010-2013 Peer-reviewed

Hirono Otomaru, Taro Kamigaki, Raita Tamaki, Jamie Opinion, Arlene Santo, Edgard Daya, Michiko Okamoto, Mariko Saito, Veronica Tallo, Soccoro Lupisan, Akira Suzuki, Hitoshi Oshitani

PLOS ONE　10　(4)　e0123755　2015/04

DOI： 10.1371/journal.pone.0123755 　

ISSN： 1932-6203
Isolation and Characterization of Influenza C Viruses in the Philippines and Japan Peer-reviewed

Takashi Odagiri, Yoko Matsuzaki, Michiko Okamoto, Akira Suzuki, Mariko Saito, Raita Tamaki, Socorro P. Lupisan, Lydia T. Sombrero, Seiji Hongo, Hitoshi Oshitani

JOURNAL OF CLINICAL MICROBIOLOGY　53　(3)　847-858　2015/03

DOI： 10.1128/JCM.02628-14 　

ISSN： 0095-1137

eISSN： 1098-660X
Molecular Epidemiology of Enterovirus D68 from 2013 to 2014 in Philippines Peer-reviewed

Yuki Furuse, Natthawan Chaimongkol, Michiko Okamoto, Tadatsugu Imamura, Mariko Saito, Raita Tamaki, Mayuko Saito, Socorro P. Lupisan, Hitoshi Oshitani

JOURNAL OF CLINICAL MICROBIOLOGY　53　(3)　1015-1018　2015/03

DOI： 10.1128/JCM.03362-14 　

ISSN： 0095-1137

eISSN： 1098-660X
Human G3P[4] rotavirus obtained in Japan, 2013, possibly emerged through a human-equine rotavirus reassortment event Peer-reviewed

Rungnapa Malasao, Mayuko Saito, Akira Suzuki, Toshifumi Imagawa, Nao Nukiwa-Soma, Kentaro Tohma, Xiaofang Liu, Michiko Okamoto, Natthawan Chaimongkol, Clyde Dapat, Kazuhisa Kawamura, Yasuko Kayama, Yoshifumi Masago, Tatsuo Omura, Hitoshi Oshitani

VIRUS GENES　50　(1)　129-133　2015/02

DOI： 10.1007/s11262-014-1135-z 　

ISSN： 0920-8569

eISSN： 1572-994X
Characteristics of a Plasma-induced Flow using a Mesh Electrode for Viral Inactivation

Yuji Kudo, Michiko Okamoto, Takehiko Sato, Daisuke Yoshino, Akira Suzuki, Hitoshi Oshitani

Proceedings of the 14th International Symposium on Advanced Fluid Information (AFI2014)　106-107　2014/10/09
Establishment and Clinical Applications of a Portable System for Capturing Influenza Viruses Released through Coughing Peer-reviewed

Etsuko Hatagishi, Michiko Okamoto, Suguru Ohmiya, Hisakazu Yano, Toru Hori, Wakana Saito, Hiroshi Miki, Yasushi Suzuki, Reiko Saito, Taro Yamamoto, Makoto Shoji, Yoshihisa Morisaki, Soichiro Sakata, Hidekazu Nishimura

PLOS ONE　9　(8)　e103560　2014/08

DOI： 10.1371/journal.pone.0103560 　

ISSN： 1932-6203
Outbreak of Human Metapneumovirus Infection in a Severe Motor-and-Intellectual Disabilities Ward in Japan Peer-reviewed

Zifeng Yang, Akira Suzuki, Oshi Watanabe, Michiko Okamoto, Akira Ohmi, Wenbo Huang, Hidekazu Nishimura

JAPANESE JOURNAL OF INFECTIOUS DISEASES　67　(4)　318-321　2014/07

DOI： 10.7883/yoken.67.318 　

ISSN： 1344-6304

eISSN： 1884-2836
Antigenic and Receptor Binding Properties of Enterovirus 68 Peer-reviewed

Tadatsugu Imamura, Michiko Okamoto, Shin-ichi Nakakita, Akira Suzuki, Mariko Saito, Raita Tamaki, Socorro Lupisan, Chandra Nath Roy, Hiroaki Hiramatsu, Kan-etsu Sugawara, Katsumi Mizuta, Yoko Matsuzaki, Yasuo Suzuki, Hitoshi Oshitani

JOURNAL OF VIROLOGY　88　(5)　2374-2384　2014/03

DOI： 10.1128/JVI.03070-13 　

ISSN： 0022-538X

eISSN： 1098-5514
Impact of Human Adenovirus Serotype 7 in Hospitalized Children with Severe Fatal Pneumonia in the Philippines Peer-reviewed

Dai Yamamoto, Michiko Okamoto, Socorro Lupisan, Akira Suzuki, Mariko Saito, Raita Tamaki, Amado Tandoc, Edelwisa Mercado, Lydia Sombrero, Remigio Olveda, Hitoshi Oshitani

JAPANESE JOURNAL OF INFECTIOUS DISEASES　67　(2)　105-110　2014/03

DOI： 10.7883/yoken.67.105 　

ISSN： 1344-6304

eISSN： 1884-2836
Detection of enterovirus 68 in serum from pediatric patients with pneumonia and their clinical outcomes Peer-reviewed

Tadatsugu Imamura, Akira Suzuki, Socorro Lupisan, Taro Kamigaki, Michiko Okamoto, Chandra Nath Roy, Remigio Olveda, Hitoshi Oshitani

INFLUENZA AND OTHER RESPIRATORY VIRUSES　8　(1)　21-24　2014/01

DOI： 10.1111/irv.12206 　

ISSN： 1750-2640

eISSN： 1750-2659
Molecular evolution of the hemagglutinin and neuraminidase genes of pandemic (H1N1) 2009 influenza viruses in Sendai, Japan, during 2009-2011 Peer-reviewed

Irona Khandaker, Akira Suzuki, Taro Kamigaki, Kentaro Tohma, Takashi Odagiri, Takashi Okada, Ayumu Ohno, Kanako Otani, Rumi Sawayama, Kazuhisa Kawamura, Michiko Okamoto, Hitoshi Oshitani

VIRUS GENES　47　(3)　456-466　2013/12

DOI： 10.1007/s11262-013-0980-5 　

ISSN： 0920-8569

eISSN： 1572-994X
Characteristics of Non-equilibrium Plasma Flow for Viral Inactivation

Yuji Kudo, Michiko Okamoto, Daisuke Yoshino, Takehiko Sato, Akira Suzuki, Hitoshi Oshitani

Proceedings of the 13th International Symposium on Advanced Fluid Information (AFI 2013)　66-67　2013/11/26
Molecular Evolution of Enterovirus 68 Detected in the Philippines Peer-reviewed

Tadatsugu Imamura, Akira Suzuki, Socorro Lupisan, Michiko Okamoto, Rapunzel Aniceto, Rutchie J. Egos, Edgardo E. Daya, Raita Tamaki, Mariko Saito, Naoko Fuji, Chandra Nath Roy, Jaime M. Opinion, Arlene V. Santo, Noel G. Macalalad, Amado Tandoc, Lydia Sombrero, Remigio Olveda, Hitoshi Oshitani

PLOS ONE　8　(9)　e74221　2013/09

DOI： 10.1371/journal.pone.0074221 　

ISSN： 1932-6203
Genetic characterization of human respiratory syncytial virus detected in hospitalized children in the Philippines from 2008 to 2012 Peer-reviewed

Ayumu Ohno, Akira Suzuki, Socorro Lupisan, Hazel Galang, Lydia Sombrero, Rapunzel Aniceto, Michiko Okamoto, Mariko Saito, Naoko Fuji, Hirono Otomaru, Chandra Nath Roy, Dai Yamamoto, Raita Tamaki, Remigio Olveda, Hitoshi Oshitani

JOURNAL OF CLINICAL VIROLOGY　57　(1)　59-65　2013/05

DOI： 10.1016/j.jcv.2013.01.001 　

ISSN： 1386-6532
Epidemiological study of zoonoses derived from humans in captive chimpanzees Peer-reviewed

Takanori Kooriyama, Michiko Okamoto, Tomoyuki Yoshida, Toshisada Nishida, Toshio Tsubota, Akatsuki Saito, Masaki Tomonaga, Tetsuro Matsuzawa, Hirofumi Akari, Hidekazu Nishimura, Takako Miyabe-Nishiwaki

PRIMATES　54　(1)　89-98　2013/01

DOI： 10.1007/s10329-012-0320-8 　

ISSN： 0032-8332

eISSN： 1610-7365
[Researches on virology at the Tohoku University Research Center in the Philippines]. Peer-reviewed

Hitoshi Oshitani, Mariko Saito, Michiko Okamoto, Raita Tamaki, Taro Kamigaki, Akira Suzuki

Uirusu　63　(1)　45-50　2013

ISSN： 0042-6857

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Tohoku University Graduate School of Medicine has established the Tohoku-RITM Collaborative Research Center on Emerging and Re-emerging Diseases at Research Institute for Tropical Medicine (RITM) in the Philippines in 2008. Our aim of the center is to conduct operational researches, which can contribute to control of infectious diseases in the Philippines. Therefore most of our researches in the Philippines are being conducted in the fields. Main research themes include severe acute respiratory infections in children, influenza disease burden study, molecular epidemiology of rabies, and viral etiology of acute diarrhea. The study on severe acute respiratory infections in children in Leyte Island has recruited hospitalized cases with severe pneumonia. We showed that enterovirus 68 was one of important causative agents in severe pneumonia cases. We also conducted other analyses including molecular epidemiology of respiratory syncytial virus (RSV) and pathogenesis of human rhinoviruses (HRV). Based on these studies, we initiated more comprehensive researches in the Philippines since 2010.
Monitoring of Influenza Viruses in the Aftermath of the Great East Japan Earthquake Peer-reviewed

Kentaro Tohma, Akira Suzuki, Kanako Otani, Michiko Okamoto, Nao Nukiwa, Taro Kamigaki, Kazuhisa Kawamura, Hiroshi Nakagawa, Hitoshi Oshitani

JAPANESE JOURNAL OF INFECTIOUS DISEASES　65　(6)　542-544　2012/11

DOI： 10.7883/yoken.65.542 　

ISSN： 1344-6304

eISSN： 1884-2836
Human SCARB2-Dependent Infection by Coxsackievirus A7, A14, and A16 and Enterovirus 71 Peer-reviewed

Seiya Yamayoshi, Setsuko Iizuka, Teruo Yamashita, Hiroko Minagawa, Katsumi Mizuta, Michiko Okamoto, Hidekazu Nishimura, Kanako Sanjoh, Noriko Katsushima, Tsutomu Itagaki, Yukio Nagai, Ken Fujii, Satoshi Koike

JOURNAL OF VIROLOGY　86　(10)　5686-5696　2012/05

DOI： 10.1128/JVI.00020-12 　

ISSN： 0022-538X

eISSN： 1098-5514
Longitudinal Course of Human Metapneumovirus Antibody Titers and Reinfection in Healthy Adults Peer-reviewed

Michiko Okamoto, Kanetsu Sugawara, Emi Takashita, Yasushi Muraki, Seiji Hongo, Hidekazu Nishimura, Yoko Matsuzaki

JOURNAL OF MEDICAL VIROLOGY　82　(12)　2092-2096　2010/12

DOI： 10.1002/jmv.21920 　

ISSN： 0146-6615
Comparison of virus isolation using the Vero E6 cell line with real-time RT-PCR assay for the detection of human metapneumovirus Peer-reviewed

Yoko Matsuzaki, Katsumi Mizuta, Emi Takashita, Michiko Okamoto, Tsutomu Itagaki, Fumio Katsushima, Yuriko Katsushima, Yukio Nagai, Hidekazu Nishimura

BMC INFECTIOUS DISEASES　10　170　2010/06

DOI： 10.1186/1471-2334-10-170 　

ISSN： 1471-2334
Development and evaluation of a whole virus-based enzyme-linked immunosorbent assay for the detection of human metapneumovirus antibodies in human sera Peer-reviewed

Michiko Okamoto, Kanetsu Sugawara, Emi Takashita, Yasushi Muraki, Seiji Hongo, Katsumi Mizuta, Tsutomu Itagaki, Hidekazu Nishimura, Yoko Matsuzaki

JOURNAL OF VIROLOGICAL METHODS　164　(1-2)　24-29　2010/03

DOI： 10.1016/j.jviromet.2009.11.019 　

ISSN： 0166-0934
Evaluation of a New Rapid Antigen Test Using Immunochromatography for Detection of Human Metapneumovirus in Comparison with Real-Time PCR Assay Peer-reviewed

Yoko Matsuzaki, Emi Takashita, Michiko Okamoto, Katsumi Mizuta, Tsutomu Itagaki, Fumio Katsushima, Yuriko Katsushima, Yukio Nagai, Hidekazu Nishimura

JOURNAL OF CLINICAL MICROBIOLOGY　47　(9)　2981-2984　2009/09

DOI： 10.1128/JCM.00321-09 　

ISSN： 0095-1137
Cross-antigenicity among EV71 strains from different genogroups isolated in Yamagata, Japan, between 1990 and 2007 Peer-reviewed

Mizuta K, Aoki Y, Suto A, Ootani K, Katsushima N, Itagaki T, Ohmi A, Okamoto M, Nishimura H, Matsuzaki Y, Hongo S, Sugawara K, Shimizu H, Ahiko T

VACCINE　27　(24)　3153-3158　2009/05/21

DOI： 10.1016/j.vaccine.2009.03.060 　

ISSN： 0264-410X
Stability of the seven hexon hypervariable region sequences of adenovirus types 1-6 isolated in Yamagata, Japan between 1988 and 2007 Peer-reviewed

Katsumi Mizuta, Yoko Matsuzaki, Seiji Hongo, Akira Ohmi, Michiko Okamoto, Hidekazu Nishimura, Tsutomu Itagaki, Noriko Katsushima, Hitoshi Oshitani, Akira Suzuki, Yuki Furuse, Masahiro Noda, Hirokazu Kimura, Tadayuki Ahiko

VIRUS RESEARCH　140　(1-2)　32-39　2009/03

DOI： 10.1016/j.virusres.2008.10.014 　

ISSN： 0168-1702
Detection of respiratory viruses in nasopharyngeal secretions and middle ear fluid from children with acute otitis media Peer-reviewed

Hisakazu Yano, Naohiro Okitsu, Toru Hori, Oshi Watanabe, Tomoko Kisu, Etsuko Hatagishi, Akira Suzuki, Michiko Okamoto, Akira Ohmi, Mitsuko Suetake, Syun Sagai, Toshimitsu Kobayashi, Hidekazu Nishimura

ACTA OTO-LARYNGOLOGICA　129　(1)　19-24　2009

DOI： 10.1080/00016480802032777 　

ISSN： 0001-6489
[Re-evaluation of clinical utility of throat swab specimens for a rapid influenza diagnostic test]. Peer-reviewed

Shoji M, Shoji S, Okamoto M, Ohmi A, Nishimura H

Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases　83　(1)　19-25　2009/01
Publisher: The Japanese Association for Infectious Diseases
DOI： 10.11150/kansenshogakuzasshi.83.19 　

ISSN： 0387-5911

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Throat swab specimens collected from 439 patients with influenza-like symptoms visiting a clinic in the 2004-2005 influenza season were subjected to cell culture virus isolation and viral antigen detection using a rapid diagnostic kit, QuickVue Rapid SP influ (Quidel Corporation, San Diego, CA, U.S.A.). The sensitivity and specificity of diagnostic kit results were analyzed based on cell culture results, considered the diagnostic standard. Kit sensitivity was 87.8％(72/82) and specificity 90.2％(322/357) for type A influenza, and 80.4％(176/219) and 95.0％(209/220) for type B influenza, roughly comparable to results reported so far for nasopharyngeal swabs and/or nasal aspirates. Sensitivity and specificity calculated separately dividing patient age but no significant difference was seen. The antigen-detection kit thus appears clinically useful in diagnosing influenza, provided that is collected and processed properly.
Acute otitis media associated with cytomegalovirus infection in infants and children Peer-reviewed

Hisakazu Yano, Naohiro Okitsu, Oshi Watanabe, Tomoko Kisu, Toru Hori, Etsuko Hatagishi, Michiko Okamoto, Akira Ohmi, Ken-Chiro Yamada, Shun Sagai, Mitsuko Suetake, Toshimitsu Kobayashi, Hidekazu Nishimura

INTERNATIONAL JOURNAL OF PEDIATRIC OTORHINOLARYNGOLOGY　71　(9)　1443-1447　2007/09

DOI： 10.1016/j.ijport.2007.05.025 　

ISSN： 0165-5876
Outbreak of human metapneumovirus detected by use of the Vero E6 cell line in isolates collected in Yamagata, Japan, in 2004 and 2005 Peer-reviewed

C. Abiko, K. Mizuta, T. Itagaki, N. Katsushima, S. Ito, Y. Matsuzaki, M. Okamoto, H. Nishimura, Y. Aoki, T. Murata, H. Hoshina, S. Hongo, K. Ootani

Journal of Clinical Microbiology　45　(6)　1912-1919　2007/06

DOI： 10.1128/JCM.01251-06 　

ISSN： 0095-1137
[Laboratory diagnostics of viral diseases]. Peer-reviewed

Okamoto M, Nishimura H

Nihon rinsho. Japanese journal of clinical medicine　65 Suppl 2 Pt. 1　181-187　2007/02

ISSN： 0047-1852
Rapid genome sequencing of RNA viruses Peer-reviewed

Tetsuya Mizutani, Daiji Endoh, Michiko Okamoto, Kazuya Shirato, Hiroyuki Shimizu, Minetaro Arita, Shuetsu Fukushi, Masayuki Saijo, Kouji Sakai, Chang Kweng Lim, Mikako Ito, Reiko Nerome, Tomohiko Takasaki, Koji Ishii, Tetsuro Suzuki, Ichiro Kurane, Shigeru Morikawa, Hidekazu Nishimura

EMERGING INFECTIOUS DISEASES　13　(2)　322-324　2007/02

DOI： 10.3201/eid1302.061032 　

ISSN： 1080-6040
Diagnosis of human respiratory syncytial virus infection using reverse transcription loop-mediated isothermal amplification Peer-reviewed

Kazuya Shirato, Hidekazu Nishimura, Masayuki Saijo, Michiko Okamoto, Masahiro Noda, Masato Tashiro, Fumihiro Taguchi

JOURNAL OF VIROLOGICAL METHODS　139　(1)　78-84　2007/01

DOI： 10.1016/j.jviromet.2006.09.014 　

ISSN： 0166-0934

eISSN： 1879-0984
Isolation of measles virus from middle ear fluid of infants with acute otitis media Peer-reviewed

Hisakazu Yano, Mitsuko Suetake, Hiroko Endo, Reiko Takayanagi, Mika Numata, Kenji Ohyama, Shun Sagai, Naohiro Okitsu, Michiko Okamoto, Hidekazu Nishimura, Toshimitsu Kobayashi

Journal of Infection　51　(4)　e237-e240　2005/11

DOI： 10.1016/j.jinf.2004.09.002 　

ISSN： 0163-4453
Detection of human coronavirus-NL63 in children in Japan Peer-reviewed

A Suzuki, M Okamoto, A Ohmi, S Watanabe, S Miyabayashi, H Nishimura

PEDIATRIC INFECTIOUS DISEASE JOURNAL　24　(7)　645-646　2005/07

DOI： 10.1097/01.inf.0000168846.71517.ee 　

ISSN： 0891-3668
Detection of human metapneumovirus from children with acute otitis media Peer-reviewed

A Suzuki, O Watanabe, M Okamoto, H Endo, H Yano, M Suetake, H Nishimura

PEDIATRIC INFECTIOUS DISEASE JOURNAL　24　(7)　655-657　2005/07

DOI： 10.1097/01.inf.0000168755.01196.49 　

ISSN： 0891-3668
Chronological analysis on isolation of antigenic variants of A(M) influenza virus in 2002-2003 influenza season in Sendai and Fukuoka, Japan Peer-reviewed

H Nishimura, M Okamoto, A Ohmi, F Chiba, A Suzuki, O Watanabe, H Ito, M Kobayashi, M Sakurai, Y Khono, Y Nagai, Y Yamashita, S Shindo, K Shibao, Y Takasaki

OPTIONS FOR THE CONTROL OF INFLUENZA V　1263　386-389　2004

DOI： 10.1016/j.ics.2004.01.018 　

ISSN： 0531-5131
Virus isolation-based evaluation of influenza antigen rapid-detection kits with more than 3000 cases of influenza-like illness over two influenza seasons Peer-reviewed

H Nishimura, A Suzuki, O Watanabe, M Okamoto, A Ohmi, H Ito, F Chiba, Y Khono, M Sakurai, T Fukuda, T Tomaru, Y Nagai, Y Yamashita, S Shindo, K Shibao, Y Takasaki, M Shoji

OPTIONS FOR THE CONTROL OF INFLUENZA V　1263　398-401　2004

DOI： 10.1016/j.ics.2004.01.024 　

ISSN： 0531-5131

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Misc. 48

新型コロナウイルスPCR検査におけるCt値を活用した感染リスクの評価に関する検討

木村裕子, 中山麻美, 岡本道子, 勝見真琴, 阿部裕子, 藤巻慎一

日本臨床微生物学会雑誌　34　(Suppl.1)　284-284　2023/12
Publisher: (一社)日本臨床微生物学会
ISSN： 2434-866X
ウイルス培養に基づく新型コロナウイルスのPCR及び抗原定量検査のカットオフ値の検討

岡本道子, 坂本雅弘, 岸真紀子, 岡本聡, 大場千優, 齋藤繭子, 押谷仁

日本臨床微生物学会雑誌　34　(Suppl.1)　312-312　2023/12
Publisher: (一社)日本臨床微生物学会
ISSN： 2434-866X
感染管理におけるSARS-CoV-2抗原定量検査のカットオフ値の検討

菊地愛, 岡本聡, 大場千優, 松浦由美子, 皆川淳子, 岡村州博, 岡本道子

共済医報　72　(Suppl.)　128-128　2023/10
Publisher: 国家公務員共済組合連合会
ISSN： 0454-7586
米国CDCによって開発されたヒトRSウイルスのリアルタイムRT-PCR検出系の国内小児入院患者検体を用いた実際的検証

白戸憲也, 諏訪麗子, 久米庸平, 川瀬みゆき, 知識美奈, 小野貴志, 則藤桜子, 佐藤光, 岡本道子, 久間木悟, 永井幸夫, 細矢光亮, 竹田誠, 西村秀一, 橋本浩一

日本ウイルス学会学術集会プログラム・予稿集(Web)　69th　2022
当院の新型コロナウイルス変異株の検出状況および感染性リスク評価における発症日とCt値の関連性

中山麻美, 岡本道子, 馬場啓聡, 金森肇, 押谷仁

日本感染症学会東日本地方会学術集会・日本化学療法学会東日本支部総会合同学会プログラム・抄録集　71st-69th　2022
生体腎移植5年後に発症した播種性アデノウイルス感染症に急性拒絶反応を合併した一例

菅原典子, 内田奈生, 岡本道子, 石塚喜世伸, 三浦健一郎, 石田英樹, 服部元史, 呉繁夫

日本小児腎臓病学会雑誌　34　(1Suppl.)　171-171　2021/05
Publisher: (一社)日本小児腎臓病学会
ISSN： 0915-2245

eISSN： 1881-3933
ヒトメタニューモウイルス感染症に伴った急性脳症の一例

森あゆみ, 河野好彦, 西尾洋介, 福田太郎, 中村奈都紀, 野田晴香, 光松孝真, 徳毛典子, 池田麻衣子, 田中龍一, 山本ひかる, 原紳也, 岡本道子

トヨタ医報　29　44-49　2020/01
Publisher: トヨタ自動車(株)トヨタ記念病院
ISSN： 1343-9685

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1歳5ヵ月女児。発熱と頻呼吸を主訴に受診し入院となった。来院時の意識レベルはJCS 100、SpO2は96%であった。頭部MRI検査で異常所見は認められず、脳波検査で単調な徐波を認めた。咽頭ぬぐい液による迅速抗原検査でhMPV抗原が陽性となり、hMPV感染症に伴う急性脳症と診断した。ステロイドパルス療法とガンマグロブリン大量療法を行い、意識レベルの改善がみられた。入院3日目に陥没呼吸が出現し、静脈血液ガス分析で二酸化炭素の貯留を認めたためHigh flow nasal cannulaを装着し、呼吸状態は改善した。入院5日目には意識清明となり、脳波検査でも徐波が消失し、15日目に退院となった。後日、入院時の血清と1ヵ月後の血清を用いて抗hMPV IgG抗体価の測定を行ったところ、入院時は100倍未満で、1ヵ月後は6400倍に上昇していたことからhMPVの初感染と判断した。
新生児エンテロウイルス感染症3例の報告

梅津有紀子, 守谷充司, 八亀健, 川嶋有朋, 熊坂衣織, 崔裕貴, 佐藤大二郎, 山田瑛子, 星雄介, 新妻創, 高橋俊成, 小野頼母, 新田恩, 北村太郎, 村田祐二, 大浦敏博, 岡本道子

日本小児科学会雑誌　123　(8)　1330-1331　2019/08
Publisher: (公社)日本小児科学会
ISSN： 0001-6543
フィリピンの小児呼吸器疾患症例におけるエンテロウイルスD68の疫学的・臨床的解析

齊藤麻理子, 小畑, 岡本道子, 齊藤繭子, Chaimongkol Natthawan, 玉記雷太, Lupisan Socorro, 押谷仁

グローバルヘルス合同大会プログラム・抄録集　2017　314-314　2017/11
Publisher: グローバルヘルス合同大会事務局
小児におけるライノウイルスの地理的分布および5歳未満の同胞における感染リスク

佐藤彩加, 神垣太郎, 岡本道子, 玉記雷太, 押谷仁

感染症学雑誌　91　(臨増)　260-260　2017/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911

eISSN： 1884-569X
フィリピンビリラン島でのRespiratory Syncytial Virus(RSV)感染症の感染伝播の疫学

乙丸礼乃, 神垣太郎, 玉記雷太, 岡本道子, 押谷仁

感染症学雑誌　91　(臨増)　380-380　2017/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911

eISSN： 1884-569X
当科で経験したEV-D68感染症17例の臨床的検討 RSV感染症32例との比較

目時嵩也, 岡本道子, 鈴木陽, 三浦舞子, 渡邊庸平, 野口里恵, 大沼良一, 貴田岡節子, 押谷仁, 久間木悟

日本小児科学会雑誌　121　(2)　317-317　2017/02
Publisher: (公社)日本小児科学会
ISSN： 0001-6543
当科で経験したエンテロウイルスD68(EV-D68)感染症17例の臨床的検討 RSウイルス感染症32例との比較

目時嵩也, 三浦舞子, 宮林広樹, 六郷由佳, 佐藤大記, 渡邊庸平, 野口里恵, 大沼良一, 渡邉浩司, 貴田岡節子, 久間木悟, 岡本道子, 押谷仁, 大宮卓, 佐藤光, 西村秀一, 鈴木陽

日本小児科学会雑誌　121　(1)　123-123　2017/01
Publisher: (公社)日本小児科学会
ISSN： 0001-6543
胃の消化不良症状に始まり軽度の下痢症状に終わったサポウイルス感染の成人男性の一症例の詳細

西村秀一, 佐藤光, 大宮卓, 鵜飼克明, 植木洋, 岡本道子

感染症学雑誌　90　(臨増)　259-259　2016/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
繰り返される急性呼吸器感染症の危険因子に関する、起因ウイルスに基づく解析(コホート研究)

古瀬祐気, 岡本道子, 押谷仁

感染症学雑誌　90　(臨増)　265-265　2016/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
仙台市における2015年9月から10月のエンテロウイルスD68を含む呼吸器ウイルスの流行

岡本道子, 大宮卓, 佐藤光, 伊藤洋子, 西村秀一, 押谷仁, 久間木悟, 貴田岡節子

感染症学雑誌　90　(臨増)　266-266　2016/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
THE PREVALENCE AND GENETIC DIVERSITY OF SAPOVIRUS IN A NESTED CASE-CONTROL STUDY OF A PERUVIAN PERI-URBAN COMMUNITY

Xiaofang Liu, Holger Mayta, Robert H. Gilman, Michiko Okamoto, Lilia Cabrera, Jean E. Crabtree, Vitaliano Cama, Mayuko Saito, Hitoshi Oshitani

AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE　93　(4)　443-443　2015/10

ISSN： 0002-9637

eISSN： 1476-1645
【感染症研究国際ネットワーク研究の現状】海外拠点におけるウイルス感染症研究フィリピン共和国拠点

押谷仁, 齊藤麻理子, 神垣太郎, 岡本道子, 玉記雷太, 斉藤繭子

化学療法の領域　30　(6)　1266-1273　2014/05
Publisher: (株)医薬ジャーナル社
ISSN： 0913-2384
中部ベトナムにおけるRSV‐A ON1遺伝子型の発生と小児呼吸器疾患の重症化の関連性

吉原圭亮, MHLH Le Nhat, 樋泉道子, 岡本道子, 押谷仁, 鈴木基, 森内浩幸, 橋爪真弘, ANH Dang Duc, 有吉紅也, 吉田レイミント

日本小児感染症学会総会・学術集会プログラム・抄録集　46th　258　2014
315 Characteristics of cold plasma flow for viral inactivation

Kudo Yuji, Okamoto Michiko, Sato Takehiko, Yoshino Daisuke, Suzuki Akira, Oshitani Hitoshi

Symposium on Environmental Engineering　2013　(23)　220-221　2013/07/09
Publisher: The Japan Society of Mechanical Engineers

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In recent years, pandemic outbreak due to a mutation of virus is paid close attention as a big problem that may collapse social order. Generally, the methods for preventing and healing disease by the virus depend on medical agents s uch as the vaccine or antiviral drug. However, the vaccine and antiviral drug could be poorly supplied when the pandemic occurred. Plasma has been proven to be capable of sterilizing bacteria and expected to inactivate the virus. In this study, we focused on the effect of chemical species generated by plasma flow on influenza viruses.
【海外拠点におけるウイルス感染症研究】フィリピンにおける東北大学のウイルス研究の取り組み

押谷仁, 齊藤麻理子, 岡本道子, 玉記雷太, 神垣太郎, 鈴木陽

ウイルス　63　(1)　45-50　2013/06
Publisher: 日本ウイルス学会
ISSN： 0042-6857

eISSN： 1884-3433
抗ウイルス能を有する新規多孔性材料の開発と評価

蛭子貴文, 久保拓也, 岡本道子, 鈴木陽, 押谷仁, 伊藤晴香, 細矢憲

日本分析化学会講演要旨集　60年会　289-289　2011/08
Publisher: (公社)日本分析化学会
震災後のインフルエンザウイルスモニタリング

当广謙太郎, 大谷可菜子, 岡本道子, 神垣太郎, 鈴木陽, 川村和久, 中川洋, 押谷仁

東北公衆衛生学会誌　(60)　20-20　2011/07
Publisher: 東北公衆衛生学会
ISSN： 0915-549X
SEROLOGICAL SURVEY OF HUMAN PATHOGENS IN CAPTIVE CHIMPANZEES AT THE JAPANESE PRIMATE RESEARCH CENTER

Kooriyama T, Okamoto M, Nishida T, Nishimura H, Miyabe T

International Primatological Society XXIII (2010/9 Kyoto)　2010
イムノクロマトグラフィー法によるヒトメタニューモウイルス迅速診断キットの評価とウイルス分離との比較

松嵜葉子, 高下恵美, 岡本道子, 水田克巳, 板垣勉, 永井幸夫, 西村秀一

感染症学雑誌　83　(臨増)　183-183　2009/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
インフルエンザ抗原迅速検査における咽頭拭い液検体の有用性に関する再検討

庄司眞, 庄司聡, 岡本道子, 近江彰, 西村秀一

感染症学雑誌　83　(1)　19-25　2009/01
Publisher: (一社)日本感染症学会
DOI： 10.11150/kansenshogakuzasshi.83.19 　

ISSN： 0387-5911
2006/2007年に仙台市および福岡市で分離されたA/H1亜型インフルエンザウイルスの抗原解析

岡本道子, 西村秀一

感染症学雑誌　82　(6)　760-760　2008/11
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
2006/2007年に仙台市および福岡市で分離されたA/H1亜型インフルエンザウイルスの抗原解析

岡本道子, 西村秀一

感染症学雑誌　82　(臨増)　441-441　2008/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
2006/2007年に仙台市および福岡市で分離されたインフルエンザウイルスの抗原解析

岡本道子, 近江彰, 千葉ふみ子, 加藤敏夫, 西村秀一, 鈴木博義, 手塚文明

国立病院総合医学会講演抄録集　61回　444-444　2007/11
Publisher: 国立病院総合医学会
パラインフルエンザウイルス4型感染症の流行と臨床像

渡邊王志, 近江彰, 木須友子, 鈴木陽, 岡本道子, 矢野寿一, 西村秀一

小児感染免疫　19　(2)　204-204　2007/07
Publisher: 日本小児感染症学会
ISSN： 0917-4931
【新感染症学新時代の基礎・臨床研究】感染症学総論感染症の診断原因微生物の検索ウイルスの各種検査法

岡本道子, 西村秀一

日本臨床　65　(増刊2 新感染症学(上))　181-187　2007/02
Publisher: (株)日本臨床社
ISSN： 0047-1852
新興・再興感染症に備えた迅速な網羅的ウイルスゲノム検出方法(LAV法)

水谷哲也, 遠藤大二, 白戸憲也, 岡本道子, 渡辺理恵, 福士秀悦, 西條政幸, 倉根一郎, 石井孝司, 鈴木哲朗, 清水博之, 高崎智彦, 森川茂, 西村秀一

日本獣医学会学術集会講演要旨集　142回　91-91　2006/08
Publisher: (公社)日本獣医学会
ISSN： 1347-8621
LAMP法を用いたhuman metapneumovirusの検出方法の確立

鈴木陽, 岡本道子, 渡邊王志, 西村秀一

感染症学雑誌　79　(9)　795-795　2005/09
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
2004年夏のRSウイルスの流行

岡本道子, 鈴木陽, 渡邊王志, 西村秀一

感染症学雑誌　79　(8)　589-590　2005/08
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
2004年夏のRSウイルスの流行

岡本道子, 鈴木陽, 渡邊王志, 西村秀一

感染症学雑誌　79　(臨増)　151-151　2005/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
LAMP法を用いたhuman metapneumovirusの検出方法の確立

鈴木陽, 岡本道子, 渡邊王志, 西村秀一

感染症学雑誌　79　(臨増)　305-305　2005/03
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
宮城県における2001/2002シーズンインフルエンザ再流行の解析

後藤郁男, 佐藤千鶴子, 植木洋, 沖村容子, 秋山和夫, 西村秀一, 渡邉節, 山木紀彦, 野呂知世, 岡本道子

感染症学雑誌　77　(4)　259-259　2003/04
Publisher: (一社)日本感染症学会
ISSN： 0387-5911
1988〜1998年山形市周辺のパラインフルエンザウイルス感染症について

坂本美千代, 熊谷研一, 須藤なおみ, 秋葉香, 矢崎棗, 秋場伴晴, 勝島矩子, 西村秀一, 近江彰, 岡本道子, 千葉ふみ子

小児感染免疫　14　(2)　199-199　2002/07
Publisher: 日本小児感染症学会
ISSN： 0917-4931
仙台市及び山形市におけるアデノウイルス感染症の流行

岡本道子, 近江彰, 山崎孝文, 西村秀一, 手塚文明

医療　55　(増刊3)　517-517　2001/10
Publisher: (一社)国立医療学会
ISSN： 0021-1699
インフルエンザA抗原検出用キット「ディレクトジェンFluA」のウイスル検出感度についての定量的解析

近江彰, 岡本道子, 伊藤洋子, 千葉ふみ子, 山崎孝文, 西村秀一, 手塚文明

医療　55　(増刊3)　585-585　2001/10
Publisher: (一社)国立医療学会
ISSN： 0021-1699
1988年〜1998年当病院におけるインフルエンザウイルス感染症

坂本美千代, 豊田健太郎, 太田智子, 秋葉香, 矢崎棗, 秋場伴晴, 勝島矩子, 近江彰, 岡本道子

小児感染免疫　13　(1)　78-78　2001/04
Publisher: 日本小児感染症学会
ISSN： 0917-4931
山形で1986年から1998年までに急性気道感染症の小児から分離されたアデノウイルス3型の制限酵素切断パターンによる疫学解析

水田克巳, 勝島矩子, 坂本美千代, 近江彰, 岡本道子, 後藤裕子, 村田敏夫, 村山尚子, 鈴木宏

山形県衛生研究所報　33　(33)　5-8　2000/12
Publisher: 山形県衛生研究所
ISSN： 0513-4706

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アデノウイルス3型(Ad3)の疫学的特徴を決定づける為に,1992年以降1998年迄に分離されたAd3についても1991年までと同じ方法を用いて解析を行った.IIC1aは1998年終わりまで,トータルで138ヵ月ずっと存続しておりIIC1aは1987年以降の山形の優性株であり続けている.このことはAd3がコミュニティの中で小児から小児へ10年以上も遺伝子的に安定した状態で土着し存続し続けていることを示唆している.新たに出現した遺伝子型がすぐにそのまま優勢型になるとは限らない
インフルエンザワクチンの効果インフルエンザ感染の確認された症例からの検討

勝島矩子, 近江彰, 岡本道子, 西村秀一, 後藤裕子, 水田克巳, 早坂晃一

日本小児科学会雑誌　104　(10)　1052-1052　2000/10
Publisher: (公社)日本小児科学会
ISSN： 0001-6543
1997年の山形におけるアデノウイルス1-7型の血清疫学

水田克巳, 坂本美千代, 岡本道子, 後藤裕子, 村田敏夫, 村山尚子, 鈴木宏

山形県衛生研究所報　32　(32)　5-7　1999/12
Publisher: 山形県衛生研究所
ISSN： 0513-4706

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アデノウイルス(Ad)7型は山形県において1986年から1994年まで分離がみられなかったが,再興したと思われる1997年にAdの血清疫学調査を行った.Ad1,2,5,6に対する中和抗体保有率は1〜2歳齢では46.7〜93.3%で,20歳齢迄に100%に達した.Ad3に対する抗体保有率は1〜2歳齢で13.3%,5〜6歳齢でほぼ60%に達した.Ad4に対しては1〜2歳齢では0%,3歳以上で20〜40%であった.Ad7に対しては10歳齢以下では3.3〜16.7%,11〜29歳齢では0%,それ以後は加齢と共に抗体保有率が上昇した.以上よりAd7は30〜40年前に一度消滅しその後再興したものと思われた
1998年夏季に流行したEcho18型感染症の臨床

勝島矩子, 後藤裕子, 水田克巳, 近江彰, 岡本道子

日本小児科学会雑誌　103　(8)　872-872　1999/08
Publisher: (公社)日本小児科学会
ISSN： 0001-6543
重症心身障害児(者)病棟におけるインフルエンザワクチンの接種経験(その2)

大島武子, 田中総一郎, 水田克巳, 手塚文明, 近江彰, 岡本道子, 山崎孝文, 鈴木博義, 鈴木宏

医療　52　(増刊)　356-356　1998/09
Publisher: (一社)国立医療学会
ISSN： 0021-1699
【感染】感染症 1996年の仙台市と山形市におけるインフルエンザC型ウイルスの流行

岡本道子

医療　51　(増刊)　609-609　1997/10
Publisher: (一社)国立医療学会
ISSN： 0021-1699
1995年度の小児急性気道感染症におけるアデノウイルス7型感染症の疫学

岡本道子

医療　50　(増刊)　373-373　1996/10
Publisher: (一社)国立医療学会
ISSN： 0021-1699

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Books and Other Publications 1

新感染症学 : 新時代の基礎・臨床研究上

日本臨牀社

日本臨牀社　2007

Research Projects 9

免疫抑制薬投与下におけるCOVID-19ワクチン接種の有効性と安全性

岡本道子, 斉藤繭子

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(C)

Institution: 東北大学

2022/04/01 - 2025/03/31

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本研究は、新型コロナウイルスワクチン接種前後の血清において、膠原病関連疾患に罹患している患者に投与されている疾患修飾性抗リウマチ薬やステロイドの数や量、疾患の種類や重症度、年齢総などの背景因子によって、ワクチンにより得られる抗新型コロナウイルス抗体価（血清中の濃度）上昇に差があるか、またワクチン接種による副反応や疾患活動性の変化が生じるかを評価することを目的とした前向きコホート研究である。東京都内総合病院と埼玉県内にある膠原病専門内科医院の2施設で患者登録を行い、2023年3月までに登録された膠原病関連症例数は合計358例で、受診科の内訳は膠原病・リウマチ関連症例259例、呼吸器病関連 99例であった。3回目のワクチン（ブースター）接種前より、膠原病関連症例の対象として病院勤務者の取り込みも行い、210名が登録された。4回目接種の施行に伴い、研究期間の延長の承諾を得て追跡可能であった研究参加者からは 4回目接種後まで血清検体の収集を行った。このうち、膠原病関連症例のワクチン2回目接種直後、2回目接種から半年後または3回目接種直前、3回目接種直後の血清検体における新型コロナウイルスの抗スパイク（S）蛋白に対するIgG抗体価を比較したところ、3回目接種直後の抗体価は、2回目接種後の抗体価と比較して治療薬によらず高い傾向が認められた。臨床・疫学的背景因子の詳細、投薬内容を含めたデータ解析を進めている。
Detection of host risk factors of SARS CoV-2 infection in exosomes and other extracellular vesicles in saliva

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Research (Exploratory)

Institution: Tohoku University

2021/07/09 - 2024/03/31
Analysis of molecular evolution of various respiratory viruses in an area of the Philippines

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

Institution: Tohoku University

2019/10/07 - 2024/03/31
Epidemiological study for control of respiratory syncytial virus from a global perspective

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2019/04/01 - 2023/03/31
エンテロウイルスD68型の抗体保有状況の推移と流行の関連 Competitive

岡本道子

Offer Organization: 日本学術振興会：科学研究費助成事業

System: 基盤研究(C)

2017/04 - 2020/03
Transmission dynamics of Respiratory Syncytial Virus and Establishing New Control Measures

Oshitani Hitoshi, Okamoto Michiko, Saito Mariko, Furuse Yuki, Otomaru Hirono, Ueno Fumihiko, Clyde Dapat, LUPISAN Socorro P., TALLO Veronica, ALDAY Portia P., MERCADO Edelwisa S., Sirjan Bastola, Malasao Rungnapa, Alexander Burmaa, Od Isn

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2016/04/01 - 2019/03/31

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We conducted a cohort study in the Philippines, which focused on RSV(Respiratory Syncytial Virus) and virological and epidemiological analyses were conducted. We revealed that some amino acid substitutions might be involved for repeated infections with RSV. We also calculated the age-specific incidence of RSV and identified older children as an important source of RSV infection for infants. We also conducted a cohort study in Mongolia and revealed transmission patterns of RSV in the community. In Zambia, we started a preliminary sequence analysis of RSV and identified a unique mutation in analyzed viruses.
Epidemiological study on influenza seasonality and an association with its dynamics in school children

Kamigaki Taro, OTOMARU HIRONO, OKAMOTO MICHIKO, OSHITANI HITOSHI, Chaw Liling, Alexander Burmaa, Oyungerel Darmaa, Nymadawa Pagbajab, Alday Portia, Tan Alvin, Tallo Veronica

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2015/04/01 - 2019/03/31

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Although disease burden of influenza in Asian developing countries is similar to that in developed countries, its epidemic characteristics (especially seasonality) is very different. In this study, we conducted epidemiological studies of influenza in two countries; the Philippines and Mongolia. In the Philippines, we calculated incidence rate by considering a fraction of health seeking and revealed that it could increase up to three times. In Mongolia, a field study was conducted in a suburb district of Ulaanbaatar, and it was revealed that the frequency of tachycardia is significantly higher in hospitalized children with influenza compared with respiratory rates and SpO2 measurement. In addition, we found that the highest number of outpatient children with influenza was 1-4 years old than that in school children.
Molecular Mechanisms a Novel Genotype of Respiratory Syncytial Virus Replaced Old One

Furuse Yuki, Oshitnai Hitoshi, Okamoto Michiko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

2016/04/01 - 2018/03/31

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Respiratory syncytial virus (RSV) is a major cause of bronchiolitis among young children. In the study project, we analyzed a new genotype of the virus, ON1. We identified genetic signature of the ON1 RSV by whole genome sequencing. Phylogenetic analysis with the sequence data revealed evolutionary pathway that the ON1 RSV had generated. Mathematical modelling found immunological difference and seasonality as factors responsible for replacement of circulating genotypes of the virus. We also found a phenotypic difference between the ON1 and a former genotype of the virus in infection model with isolated virus and human airway-derived cells. Further study would unveil molecular mechanisms underlying difference between the genotypes.
Transmission dynamics and evolution of influenza viruses in Asia

Oshitani Hitoshi, KAMIGAKI Taro, SUZUKI Akira, SAITO Mariko, OKAMOTO Michiko, SAITO Mayuko, TAMAKI Raita, FURUSE Yuki, NUKIWA Nao, KHANDAKER Irona, OKADA Takashi, ODAGIRI Takashi, IMAGAWA Toshifumi, MIMURA Satoshi, IMAMURA Tadatsugu, KOSAI Hisato, CHAW Liling, Liu XIAOFANG, Ngako Kadji Francois Marie, OHNO Ayumu, OTOMARU Hisano, TOHMA Kentaro, OHTANI Kanako, Huo Xiang, TAKAHASHI Yoshihiro, FUJI Naoko, MATSUZAKI Yoko, HONGO Seiji, Lupisan S., Tandoc A., Tallo V., Tan A., Alday P., Nymadawa P., Nyamaa G., Burmaa A., Darmaa B., Bayasgalan N., Od I., Tsatsral S., Maitsetseg C.

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2012/04/01 - 2016/03/31

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Transmission dynamics of influenza viruses were analyzed in study sites in three countries; Philippines, Mongolia and Japan. Enhanced surveillance was conducted in Baguio City and Tacloban City in the Philippines and Odate City of Akita Prefecture in Japan, while the community-based cohort study was conducted in Baganuur District of Ulaanbataar City in Mongolia. Through these studies some important epidemiological findings have been obtained, which include; 1) significant role of children in transmission of influenza viruses, 2) transmission and maintenance mechanism of influenza viruses in the Philippines, which is located in tropical area, 3) low incidence of influenza in infants and pregnant women in Mongolia.

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