Details of the Researcher

PHOTO

Mariko Saito
Section
Graduate School of Medicine
Job title
Associate Professor
Degree

  • PhD (Clinical Pharmacy) (Nagasaki University)

Research History 5

  • 2025/10 - Present
    Tohoku University Graduate School of Medicine　International Exchange Office　Associate Professor

  • 2018/01 - 2025/09
    Tohoku University Graduate School of Medicine,　International Exchange Office　Assistant Professor

  • 2007/10 - 2025/09
    Tohoku University Graduate School of Medicine　Department of Virology　Assistant Professor

  • 2008/10 - 2018/01
    RITM-Tohoku Collaborative Research Center on Emerging and Re-emerging Infectious Diseases (Manila, Philippines)　Head

  • 2005/04 - 2007/09
    Nagasaki University Institute of Tropical Medicine　Department of Internal Medicine　COE (Center of Excellence) Researcher

Research Areas 2

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

  • Life sciences / Virology /

Papers 77

  1. Molecular analysis of influenza A(H3N2) in a remote tropical island during 2014-2019 to identify the frequency of introduction and local circulation

    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　2025/05

    DOI： 10.1016/j.ijid.2025.107864 　

  2. Norovirus-associated diarrhea and asymptomatic infection in children aged under 4 years: a community-cohort study in the Philippines

    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　2025/03

    DOI： 10.1016/j.ijregi.2024.100549 　

  3. Puppies as the primary causal animal for human rabies cases: three-year prospective study of human rabies in the Philippines. International-journal

    Nobuo Saito, Karren L Inton, Jaira D Mauhay, Rontgene M Solante, Ferdinand D Guzman, Kentaro Yamada, Yasuhiko Kamiya, Mariko Saito-Obata, Beatriz P Quiambao, Takaaki Yahiro, Kazunori Kimitsuki, Akira Nishizono

    Frontiers in microbiology　15　1425766-1425766　2024

    DOI： 10.3389/fmicb.2024.1425766 　

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    INTRODUCTION: While rabies remains a global concern, detailed studies on human rabies, particularly regarding causal animals and the reasons for not receiving postexposure prophylaxis (PEP), are lacking. METHODS: We conducted a 3-year prospective study (October 2019-September 2022) at the Philippines' largest rabies referral center. We interviewed patients with suspected rabies and their families. We used LN34 qRT-PCR and rapid fluorescent focus inhibition test on saliva samples. We also compared our findings with two retrospective studies at the same hospital. RESULTS: We enrolled 151 patients, including 131 with potential rabies exposure. Similar to retrospective studies, the participants were predominantly males (75.5%), adults (76.8%), low-income individuals (91.4%), and rural dwellers (62.3%). The causal animals were mainly dogs (97.0%), with similar incubation periods, clinical symptoms, and a high proportion not receiving vaccines or immunoglobulins (93.2%). Most causal animals were owned by either the patients' households or their neighbors (60.2%), with a significant proportion being puppies (58.8%). Most patients had knowledge of rabies; however, reasons for not seeking PEP included misconceptions about minor bites not causing rabies (51.3%), beliefs in traditional healers (33.9%), and economic constraints (22.6%). Despite completing the WHO regimen, two PEP failures were observed. LN34 qRT-PCR detected 98 positive cases (sensitivity, 64.9%; 95% CI 56.7-72.5). These strains belong to the Southeast Asia 4 subclade. DISCUSSION: In conclusion, this study highlights the role of puppies as primary causal animals and the presence of misconceptions that preclude patients from acquiring PEP.

  4. 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　77　(11)　1612-1613　2023/07/20

    DOI： 10.1093/cid/ciad430 　

  5. Molecular Analysis of Rabies Virus Using RNA Extracted from Used Lateral Flow Devices. International-journal

    Jaira D Mauhay, Nobuo Saito, Kazunori Kimitsuki, Milagros R Mananggit, Jeffrey L Cruz, Maria G Lagayan, Alyssa M Garcia, Patricia M Lacanilao, Kentaro Yamada, Mariko Saito-Obata, Daria L Manalo, Catalino S Demetria, Beatriz P Quiambao, Akira Nishizono

    Journal of clinical microbiology　61　(3)　e0154322　2023/02/22

    DOI： 10.1128/jcm.01543-22 　

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    Molecular analysis of rabies virus can provide accurate diagnosis and information on its genetic diversity. The transportation of rabies brain samples from remote areas to a central laboratory is challenging owing to biohazard risks and decomposability. We investigated the utility of used lateral flow devices (LFDs) for subsequent molecular analysis and assessed the necessary storage temperatures. Using RNA extracted from used LFD strips, we performed conventional reverse transcription-PCR (RT-PCR) using an LN34 primer set to amplify short fragments (165 bp) for rabies virus detection and the P1-304 primer set to amplify long fragments of the entire N gene amplicon (1,506 bp) for phylogenetic analysis. Among 71 used LFDs stored in a refrigerator and 64 used LFDs stored at room temperature, the LN34 assay showed high sensitivities (96.2% and 100%, respectively) for the diagnosis of rabies, regardless of the storage temperature. A significant reduction in the sensitivity of rabies diagnosis was observed when using the P1-304 primer set for used LFDs stored at room temperature compared to those stored at refrigeration temperature (20.9% versus 100%; P < 0.05). Subsequent sequencing and phylogenetic analysis were successfully performed using the amplicons generated by the P1-304 RT-PCR assays. Used LFDs are thus promising resources for rabies virus RNA detection and sequence analysis. Virus detection via RT-PCR, amplifying a short fragment, was possible regardless of the storage temperature of the used LFDs. However, refrigerated storage is recommended for RT-PCR amplification of long fragments for phylogenetic analysis.

  6. 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.

  7. 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.

  8. フィリピン中央ルソン地域における狂犬病ウイルスの分子疫学研究 2004年-2019年(Molecular Epidemiology of Rabies virus in the Central Luzon Region, Philippines: 2004 to 2019)

    齊藤 麻理子[小畑], 松原 光希, 君付 和範, 齊藤 信夫, Mananggit Milagros, Demetria Catalino, Manalo Daria, Quiambao Beatriz, 西園 晃

    日本渡航医学会誌　16　(Suppl.)　140-140　2022/09

    Publisher: (一社)日本渡航医学会

    ISSN： 1883-8065

  9. Japanese encephalitis virus genotype III from mosquitoes in Tarlac, Philippines. International-journal

    Wilfredo E Aure, Yusuke Sayama, Mariko Saito-Obata, Nelia P Salazar, Fedelino F Malbas Jr, Hazel O Galang, Tadatsugu Imamura, Cecilia L Zuasula, Hitoshi Oshitani

    IJID regions　4　59-65　2022/09

    DOI： 10.1016/j.ijregi.2022.05.005 　

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    OBJECTIVES: The aim of this study was to investigate the presence of Japanese encephalitis virus (JEV) in a rice-farming community in the Philippines and to determine its implications regarding the epidemiology of viral encephalitides in the Asia-Pacific Region. METHODS: Mosquitoes were collected monthly from animal-baited traps close to flooded rice fields in two barangays (villages) in the Municipality of San Jose, Tarlac Province in Luzon, from May 2009 to July 2010. Virus was detected by nested reverse transcription PCR. Phylogenetic analysis of the amplified virus envelope gene was done using the maximum-likelihood method. RESULTS: A total of 28 700 known vector mosquitoes were collected, namely Culex vishnui, Culex fuscocephala, Culex tritaeniorhynchus, and Culex gelidus. JEV genotype III was detected in C. tritaeniorhynchus, belonging to the same genotype but form a different clade from those reported in the 1980s and in 2020 in this country. CONCLUSIONS: Japanese encephalitis is associated with rice cultivation and the presence of infected mosquitoes in Tarlac, Philippines. It remains to be seen whether the observed genetic shift of genotype III to genotype I in Asia will in time have an impact on the epidemiology of Japanese encephalitis in the Philippines. For long-term disease control, regular surveillance and Japanese encephalitis immunization in children and travelers in high risk areas are recommended.

  10. 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.

  11. 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.

  12. 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.

  13. Lateral flow devices for samples collected by straw sampling method for postmortem canine rabies diagnosis. International-journal Peer-reviewed

    Milagros R Mananggit, Daria L Manalo, Nobuo Saito, Kazunori Kimitsuki, Alyssa Marie G Garcia, Patricia Mae T Lacanilao, Joely T Ongtangco, Cornhlo R Velasco, Maria Victoria A Del Rosario, Maria Glofezita O Lagayan, Kentaro Yamada, Chun-Ho Park, Satoshi Inoue, Motoi Suzuki, Mariko Saito-Obata, Yasuhiko Kamiya, Catalino S Demetria, Beatriz P Quiambao, Akira Nishizono

    PLoS neglected tropical diseases　15　(12)　e0009891　2021/12

    DOI： 10.1371/journal.pntd.0009891 　

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    The direct fluorescent antibody test (dFAT) using brain sample after opening the skull is the standard rabies diagnostic test in animal rabies. However, it is not feasible in many resource-limited settings. Lateral flow devices (LFD) combined with a simple sampling methodology is quicker, simpler, and less hazardous than the standard test and can be a useful tool. We conducted a prospective on-site study to evaluate the diagnostic accuracy of the LFD with the straw sampling method compared with that of the dFAT with the skull opening procedure for post-mortem canine rabies diagnosis. We collected 97 rabies-suspected animals between December 1, 2020 and March 31, 2021. Among the 97 samples, 53 and 50 cases were positive tests for dFAT and LFD, respectively. The sensitivity and specificity of LFD with straw sampling method were 94.3% (95% confidence interval [CI], 84.3-98.8%) and 100% (95% CI, 92.0-100%), respectively. The performance of LFD by the straw sampling method showed relatively high sensitivity and 100% specificity compared with that of dFAT performed on samples collected after opening the skull. This methodology can be beneficial and is a strong tool to overcome limited animal surveillance in remote areas. However, because of our limited sample size, more data using fresh samples on-site and the optimizations are urgently needed for the further implementation in endemic areas.

  14. Molecular characterization of Vibrio cholerae O1 isolates obtained from outbreaks in the Philippines, 2015-2016. International-journal Peer-reviewed

    Mark Philip Bugayong, Hidemasa Izumiya, Josie M Bilar, Masatomo Morita, Eiji Arakawa, Mariko Saito-Obata, Hitoshi Oshitani, Makoto Ohnishi

    Journal of medical microbiology　70　(11)　2021/11

    DOI： 10.1099/jmm.0.001443 　

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    Introduction. The Philippines, comprising three island groups, namely, Luzon, Visayas and Mindanao, experienced an increase in cholera outbreaks in 2016. Previous studies have shown that Vibrio cholerae isolates obtained from the Philippines are novel hybrid El Tor strains that have evolved in the country and are clearly distinct from those found in Mozambique and Cameroon.Gap statement. The characterization of the strains isolated from outbreaks has been limited to phenotypic characteristics, such as biochemical and serological characteristics, in most previous studies.Aim. We performed multilocus variable-number tandem repeat (VNTR) analysis (MLVA) for V. cholerae isolates obtained from 2015 to 2016 to further characterize and understand the emergence and dissemination of the strains in the Philippines.Methodology. A total of 139 V. cholerae O1 Ogawa biotype El Tor isolates were obtained from the Philippines during diarrhoeal outbreaks in 18 provinces between 2015 and 2016. VNTR data were analysed to classify the MLVA profiles where the large-chromosome types (LCTs) were applied for grouping.Results. We identified 50 MLVA types among 139 isolates originating from 18 provinces, and 14 LCTs. The distribution of the LCTs was variable, and a few were located in specific areas or even in specific provinces. Based on eBURST analysis, 99 isolates with 7 LCTs and 32 MLVA types belonged to 1 group, suggesting that they were related to each other. LCT A was predominant (n=67) and was isolated from Luzon and Visayas. LCT A had 14 MLVA types; however, it mostly emerged during a single quarter of a year. Eight clusters were identified, each of which involved specific MLVA type(s). The largest cluster involved 23 isolates showing 3 MLVA types, 21 of which were MLVA type A-14 isolated from Negros Occidental during quarter 4 of 2016. Comparative analysis showed that almost all isolates from the Philippines were distinct from those in other countries.Conclusions. The genotypic relationship of the V. cholerae isolates obtained during outbreaks in the Philippines was studied, and their emergence and dissemination were elucidated. MLVA revealed the short-term dynamics of V. cholerae genotypes in the Philippines.

  15. 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.

  16. Background and descriptive features of rabies-suspected animals in Central Luzon, Philippines. Peer-reviewed

    Milagros R Mananggit, Kazunori Kimitsuki, Nobuo Saito, Alyssa Marie G Garcia, Patricia Mae T Lacanilao, Joely T Ongtangco, Cornelio R Velasco, Maria Victoria D Rosario, Maria Glofezita O Lagayan, Kentaro Yamada, Chun-Ho Park, Satoshi Inoue, Motoi Suzuki, Mariko Saito-Obata, Yasuhiko Kamiya, Daria L Manalo, Catalino S Demetria, Beatriz P Quiambao, Akira Nishizono

    Tropical medicine and health　49　(1)　59-59　2021/07/28

    DOI： 10.1186/s41182-021-00351-x 　

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    BACKGROUND: The Philippines is one of the major endemic countries for canine rabies in Southeast Asia. However, detailed description and analysis of laboratory-confirmed animal rabies are limited. Highly accurate surveillance requires a thorough understanding of the target area-specific problems and obstacles. Therefore, we aim to describe and analyze the rabies suspect animals in Central Luzon, Philippines, to clarify the characteristics of management and clinical signs by conducting interviews with the owners. METHODS: We prospectively collected information on the rabies suspect animals submitted to the Regional animal laboratory in Central Luzon through passive laboratory-based rabies surveillance between 1st April 2019 and 30th September 2020. We performed active interviews directly or telephonically with the owner. The direct fluorescent antibody test was performed on the hippocampus, brain stem, and cerebellum for laboratory confirmation. Descriptive statistics were used to characterize the number of rabies cases according to management methods and characteristics of suspected animals during the observation period. Clinical symptoms of suspected rabid animals were analyzed by univariate logistic regression analysis. RESULTS: There were 292 sample submissions during the study period. Of these, 160 were positive for dFAT. Samples of pet animals (85.3%) provided by owners or their acquaintances (59.2%) accounted for the majority of laboratory confirmed cases. Case mapping showed that more rabies-suspected cases were sent from areas near the regional laboratory than from those far from the laboratory, despite the incidence of rabies being high in these areas. The management and clinical symptoms of 227 animal cases showed that most owners were managing their animals at home and were allowing them to roam outside (69.6%) and be unvaccinated (78.9%). Rabid animals were more likely to manifest aimless running, restlessness, and agitation. CONCLUSIONS: Our study provided some features of animals with laboratory-confirmed rabies in Central Luzon. However, most of the samples were submitted from areas near the rabies diagnosis laboratory, and the number of samples submitted from remote areas was low. To improve the surveillance capacity, it is necessary to increase sample submissions from remote areas.

  17. Validation of serum apolipoprotein A1 in rabies virus-infected mice as a biomarker for the preclinical diagnosis of rabies. International-journal Peer-reviewed

    Kentaro Yamada, Koji Kuribayashi, Naotaka Inomata, Kazuko Noguchi, Kazunori Kimitsuki, Catalino S Demetria, Nobuo Saito, Satoshi Inoue, Chun-Ho Park, Ryo Kaimori, Motoi Suzuki, Mariko Saito-Obata, Yasuhiko Kamiya, Daria L Manalo, Beatriz P Quiambao, Akira Nishizono

    Microbiology and immunology　65　(10)　438-448　2021/07/16

    DOI： 10.1111/1348-0421.12929 　

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    Rabies is a type of acute fetal encephalitis caused by rabies virus (RABV). While it becomes incurable after symptom onset, it can be prevented by post-exposure prophylaxis (PEP) during the long incubation period. While preclinical diagnosis aids the appropriate PEP administration, it is mostly nonfeasible owing to the absence of viremia or a specific antibody response during the incubation period. Here, an attempt was made to identify a serum biomarker for the preclinical diagnosis of rabies. Using the serum from a mouse inoculated intramuscularly (i.m.) with 5 × 105 focus-forming units (FFU) of recombinant RABV expressing red firefly luciferase (1088/RFLuc) immediately before symptom onset, two-dimensional differential gel electrophoresis was conducted, followed by mass spectrometry, and it was confirmed that apolipoprotein A1 (ApoA1) was up-regulated. ELISA showed that the serum ApoA1 and specific antibody levels increased during the incubation period and on the day of symptom onset. Since a lower infectious dose can be used to induce the unstable and long incubation period generally observed in natural infection, the ApoA1 level in mice inoculated i.m. with 103  FFU of 1088/RFLuc was examined by monitoring viral dynamics using in vivo imaging. The serum ApoA1 and specific antibody levels were up-regulated in 50% and 58.3% of mice exhibiting robust RABV replication, respectively, but not in mice exhibiting weak RABV replication. In addition, it was reported that ApoA1 was found to be a biomarker for neuronal damage. Additional biomarker candidates will be needed for the effective preclinical diagnosis of rabies.

  18. 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

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/aje/kwab181 　

    ISSN： 0002-9262

    eISSN： 1476-6256

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    <title>Abstract</title> 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.

  19. 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　2021/07

    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.

  20. Surveillance of dengue virus in individual Aedes aegypti mosquitoes collected concurrently with suspected human cases in Tarlac City, Philippines International-journal Peer-reviewed

    Jean Claude Balingit, Thaddeus M. Carvajal, Mariko Saito-Obata, Maribet Gamboa, Amalea Dulcene Nicolasora, Ava Kristy Sy, Hitoshi Oshitani, Kozo Watanabe

    Parasites & Vectors　13　(1)　594-594　2020/12

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s13071-020-04470-y 　

    eISSN： 1756-3305

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    <title>Abstract</title><sec> <title>Background</title> Vector control measures are critical for the prevention and reduction of dengue virus (DENV) transmission. Effective vector control is reliant not only on knowledge of mosquito abundance, but also on the timely and accurate detection of mosquito-borne infection. Mosquito-based virus surveillance programs typically rely on pool-based mosquito testing, although whether individual-based mosquito testing is a feasible alternative to this has not been widely studied. Applying an individual-based mosquito testing approach, we conducted a 1-month surveillance study of DENV in adult <italic>Aedes aegypti</italic> mosquitoes in homes of suspected dengue patients during the 2015 peak dengue season in Tarlac City, Philippines to more accurately assess the mosquito infection rate and identify the DENV serotypes and genotypes concurrently co-circulating in mosquitoes and patients there. </sec><sec> <title>Methods</title> We performed a one-step multiplex real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for the simultaneous detection and serotyping of DENV in patients and individual female <italic>Ae. aegypti</italic> mosquitoes. Additionally, we performed sequencing and phylogenetic analyses to further characterize the detected DENV serotypes in mosquitoes and patients at the genotype level. </sec><sec> <title>Results</title> We collected a total of 583 adult <italic>Ae. aegypti</italic> mosquitoes, of which we individually tested 359 female mosquitoes for the presence of DENV. Ten (2.8%) of the 359 female mosquitoes were positive for the presence of DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which was consistent with the serotypes concurrently found in infected patients. Sequencing and phylogenetic analyses of the detected DENV serotypes based on the partial sequence of the evelope (<italic>E</italic>) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely DENV-1 genotype IV, DENV-2 Cosmopolitan genotype, and DENV-4 genotype II. </sec><sec> <title>Conclusions</title> We demonstrated the utility of a one-step multiplex real-time RT-PCR assay for the individual-based DENV surveillance of mosquitoes. Our findings reinforce the importance of detecting and monitoring virus activity in local mosquito populations, which are critical for dengue prevention and control. </sec>

  21. Evaluation of the diagnostic accuracy of lateral flow devices as a tool to diagnose rabies in post-mortem animals International-journal Peer-reviewed

    Kazunori Kimitsuki, Nobuo Saito, Kentaro Yamada, Chun-Ho Park, Satoshi Inoue, Motoi Suzuki, Mariko Saito-Obata, Yasuhiko Kamiya, Daria L. Manalo, Catalino S. Demetria, Milagros R. Mananggit, Beatriz P. Quiambao, Akira Nishizono

    PLOS Neglected Tropical Diseases　14　(11)　e0008844-e0008844　2020/11/05

    Publisher: Public Library of Science (PLoS)

    DOI： 10.1371/journal.pntd.0008844 　

    eISSN： 1935-2735

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    Implementation of lateral flow devices (LFDs) for rabies antigen detection is expected to improve surveillance through the efficient detection of rabid animals in resource-limited settings; however, the use of LFDs for diagnosis remains controversial because some commercially available kits show low sensitivity. Therefore, we compared the diagnostic efficacy of three LFDs (ADTEC, Bionote, and Elabscience kits) paralleled with the direct fluorescent antibody test (dFAT) using fresh samples and investigated the diagnostic accuracies. To do so, we evaluated rabies-suspected samples submitted to the Regional Animal Disease Diagnostic Laboratory III, Philippines. Furthermore, we conducted real-time RT-PCR and sequencing to measure the accuracy of field laboratory diagnosis. The total number of animals submitted during this study period was 184 cases, including negative control samples. Of these, 53.9% (84 cases) were positive in the dFAT. Dogs were the most common rabies-suspected animal (n = 135). The sensitivities of the ADTEC and Bionote kits were 0.88 (74 cases) and 0.95 (80 cases), respectively. The specificity of both kits was 1.00 (100 cases). Furthermore, the sensitivity and specificity of the ADTEC kit after directly homogenizing the samples in assay buffer without dilution in phosphate-buffered saline (ADTEC kit DM) were 0.94 (79 cases) and 1.00 (100 cases), respectively. By contrast, there were no positive results using the Elabscience kit among all dFAT-positive samples. The sensitivity and specificity of LFDs make these tests highly feasible if properly used. Therefore, LFD tests can be used to strengthen the surveillance of rabies-infected animals in endemic and resource-limited settings.

  22. Individual-based dengue virus surveillance in Aedes aegypti mosquitoes collected concurrently with suspected patients in Tarlac City, Philippines Peer-reviewed

    Jean Claude Balingit, Thaddeus M. Carvajal, Mariko Saito-Obata, Maribet Gamboa, Amalea Dulcene Nicolasora, Ava Kristy Sy, Hitoshi Oshitani, Kozo Watanabe

    2020/08/11

    Publisher: Research Square

    DOI： 10.21203/rs.3.rs-56950/v1 　

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    <title>Abstract</title> Background Dengue virus (DENV) infection continues to be a major public health concern throughout tropical and subtropical regions of the world where Aedes aegypti mosquitoes, its primary vector, dwell. In the context of DENV transmission, effective control is reliant not only on knowledge of mosquito abundance, but also on mosquito infection. In the 2015 dengue season, we conducted a one-month entomological surveillance of adult Aedes aegypti mosquitoes around households of suspected dengue patients in Tarlac City, Philippines to assess the DENV infection rate in the local mosquito population, and to identify the DENV genotypes and serotypes concurrently co-circulating in mosquitoes and patients. Methods We performed a one-step multiplex real-time RT-PCR assay for the simultaneous detection and serotyping of DENV in patients and in individual female Aedes aegypti mosquito. Consequently, we performed sequencing and phylogenetic analyses to further characterize the detected DENVs in mosquitoes and patients at the genotype level. Results We collected a total of 583 adult Aedes aegypti mosquitoes, of which we tested 359 female mosquitoes individually for the presence of the DENV. Ten mosquitoes (2.8%) from amongst 359 female mosquitoes were confirmed to be positive for the presence of the DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which were consistent with the serotypes concurrently infecting patients. Sequencing and phylogenetic analyses of the detected DENVs based on the partial envelope ( E ) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely: DENV-1 genotype IV, DENV-2 Cosmopolitan genotype and DENV-4 genotype II. Notably, we observed a random geographic distribution of DENVs in the study area suggesting the occurrence of active DENV transmission within and outside the vicinities of Tarlac City. Conclusions In this study, we demonstrate the utility of an individual-based DENV surveillance in field-collected mosquitoes and the importance of incorporating mosquito virus data in phylogenetic studies. Analyzing virus sequences from vector and host could potentially improve our understanding of the dynamics of DENV transmission.

  23. Genetic diversity of species A rotaviruses detected in clinical and environmental samples, including porcine-like rotaviruses from hospitalized children in the Philippines. International-journal Peer-reviewed

    Toshifumi Imagawa, Mayuko Saito, Dai Yamamoto, Mariko Saito-Obata, Yoshifumi Masago, Adrianne C Ablola, Amado O Tandoc 3rd, Edelwisa Segubre-Mercado, Socorro P Lupisan, Hitoshi Oshitani

    Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases　85　104465-104465　2020/07/17

    DOI： 10.1016/j.meegid.2020.104465 　

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    Rotaviruses are the major cause of severe acute diarrhea in infants and young children. Rotaviruses exhibit zoonosis and thereby infect both humans and animals. Viruses detected in urban rivers possibly reflect the presence of circulating viruses in the catchment. The present study investigates the genetic diversity of species A rotaviruses detected from river water and stool of hospitalized children with acute diarrhea in Tacloban City, the Philippines. Species A rotaviruses were detected by real-time RT-PCR and their genotypes were identified by multiplex PCR and sequencing of partial regions of VP7 and VP4. Rotaviruses were detected in 85.7% (30/35) of the river water samples and 62.7% (151/241) of the clinical samples. Genotypes of VP7 in the river water samples were G1, G2, G3, G4, G5, and G9, and those of VP4 were P[3], P[4], P[6], P[8], and P[13]. Genotypes of viruses from the clinical samples were G2P[4], G1P[8], G3P[8], G4P[6], G5P[6], and G9P[8]. Among those, G2P[4] in clinical samples (77.9%, 81/104) and P[4] of VP4 in river water samples (67.5%, 56/83)) were the most frequently detected rotavirus genotypes. However, G5 was the more frequently detected than G2 in the river water samples (42% vs. 13%) which may be originated from porcine rotavirus. Sequence analyses of eleven gene segments revealed one G5P[6] and two G4P[6] rotaviruses in the clinical samples, wherein, several gene segments were closely related to porcine rotaviruses. The constellation of these rotavirus genes suggests the emergence of reassortment between human and porcine rotavirus due to interspecies transmission. Although two commercial rotavirus vaccines are available now, these vaccines are designed to confer immunity against the major human rotaviruses. Constant monitoring of viral variety in populated areas where humans and domestic animals live in close proximity provides vital information related to the diversity of rotaviruses in a human population.

  24. Environmental Presence and Genetic Characteristics of Carbapenemase-Producing Enterobacteriaceae from Hospital Sewage and River Water in the Philippines. International-journal Peer-reviewed

    Yuki Suzuki, Pearl Joy Nazareno, Ryuichi Nakano, Melisa Mondoy, Akiyo Nakano, Mark Philip Bugayong, Josie Bilar, Mauricio Perez 5th, Emarld Julian Medina, Mariko Saito-Obata, Mayuko Saito, Kazutoshi Nakashima, Hitoshi Oshitani, Hisakazu Yano

    Applied and environmental microbiology　86　(2)　2020/01/07

    DOI： 10.1128/AEM.01906-19 　

    ISSN： 0099-2240

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    This study aimed to evaluate the prevalence and genetic characteristics of carbapenemase-producing Enterobacteriaceae (CPE) in hospital sewage and river water in the Philippines, which has a typical tropical maritime climate. We collected 83 water samples from 7 hospital sewage and 10 river water sites. CPE were identified using CHROMagar mSuperCARBA, and Gram-negative strains were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) or 16S rRNA gene sequencing. Resistance genes in Enterobacteriaceae strains were identified using PCR and DNA sequencing, and transferability of carbapenemase genes from the CPE was investigated with conjugation experiments. Genotyping was performed using multilocus sequence typing (MLST) for Escherichia coli and Klebsiella pneumoniae Out of 124 Enterobacteriaceae isolates, we identified 51 strains as CPE and divided these into 7 species, 11 E. coli, 14 Klebsiella spp., 15 Enterobacter spp., and 11 others, including 4 additional species. Conjugation experiments via broth mating and using E. coli J53 revealed that 24 isolates can transfer carbapenemase-encoding plasmids. MLST analysis showed that 6 of 11 E. coli isolates belonged to clonal complex 10 (CC10). Of 11 K. pneumoniae strains, 9 unique sequence types (STs) were identified, including ST147. Five types of carbapenemase genes were identified, with the most prevalent being NDM (n = 39), which is epidemic in clinical settings in the Philippines. E. coli CC10 and K. pneumoniae ST147, which are often detected in clinical settings, were the dominant strains. In summary, our results indicate that hospital sewage and river water are contaminated by CPE strains belonging to clinically important clonal groups.IMPORTANCE Carbapenemase-producing Enterobacteriaceae (CPE) cause severe health care-associated infections, and their increasing prevalence is a serious concern. Recently, natural ecosystems have been recognized as important reservoirs of antibiotic resistance genes. We investigated the prevalence and genetic characteristics of CPE isolated from the environment (hospital sewage and river water) in the Philippines and found several CPE, including Escherichia coli and other species, with different carbapenemases. The most prevalent carbapenemase gene type was NDM, which is endemic in clinical settings. This study revealed that isolates belonging to carbapenemase-producing E. coli CC10 and K. pneumoniae sequence type 147 (ST147), which are often detected in clinical settings, were dominant in the natural environment. Our work here provides a report on the presence and characteristics of CPE in the environment in the Philippines and demonstrates that both hospital sewage and river water are contaminated by CPE strains belonging to clinically important clonal groups.

  25. Development of a novel in vitro assay to evaluate environmental water using an IL-8 reporter cell line. International-journal Peer-reviewed

    Yutaka Kimura, Chizu Fujimura, Toshifumi Imagawa, Socorro P Lupisan, Mariko Saito-Obata, Mayuko Saito, Hitoshi Oshitani, Setsuya Aiba

    EXCLI journal　19　1054-1063　2020

    DOI： 10.17179/excli2020-2104 　

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    The IL-8 luciferase reporter cell line, THP-G8 cells, used in the in vitro sensitization test, OECD442E, can respond to a variety of stimuli other than haptens, such as lipopolysaccharide (LPS), other bacterial toxins, and detergents. Considering these characteristics, we examined the ability of the IL-8 luciferase assay using THP-G8 cells to evaluate water pollution. We first stimulated THP-G8 cell with various Toll-like receptor (TLR) agonists and nucleotide-binding oligomerization domain-like receptor (NLR) agonists, and found that TLR1, 2, 4, 5, 6 agonists and NOD 1, 2 agonists significantly augmented IL-8 luciferase activity (IL8LA). Then, we examined the detection threshold of LPS by THP-G8 cells, and found it 0.4 EU/ml. Next, we examined whether THP-G8 cells can differently respond to a variety of sources of environmental water around Sendai, Japan and Manila, Philippine and whether there is a correlation between the IL8LA of different sources of water and their level of endotoxin assessed by the LAL assay. There was a clear trend that the IL8LA was lower in the upper stream and higher in the downstream in both Japan and Philippine. Moreover, there was a strong correlation between the IL8LA of the environmental water and its endotoxin level. Finally, using N-acetyl-L-cysteine, an antioxidant/radical scavenger, and polymyxin B that neutralizes endotoxin, we demonstrated that there was a difference in the suppressive effects by them between the water from Japan and that from Philippine. These data suggest the potential of the IL-8 luciferase assay for evaluating environmental water pollution both quantitatively and qualitatively.

  26. 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.

  27. Molecular characterization of enterovirus-A71 in children with acute flaccid paralysis in the Philippines. International-journal Peer-reviewed

    Lea Necitas Apostol, Hiroyuki Shimizu, Akira Suzuki, Rifqiyah Nur Umami, Maria Melissa Ann Jiao, Amado Tandoc 3rd, Mariko Saito, Socorro Lupisan, Hitoshi Oshitani

    BMC infectious diseases　19　(1)　370-370　2019/05/02

    DOI： 10.1186/s12879-019-3955-x 　

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    BACKGROUND: Several inactivated enterovirus-A71 (EV-A71) vaccines are currently licensed in China; however, the development of additional EV-A71 vaccines is ongoing, necessitating extensive analysis of the molecular epidemiology of the virus worldwide. Until 2012, laboratory confirmation of EV-A71 for hand, foot, and mouth disease (HFMD) and other associated diseases had not occurred in the Philippines. Because EV-A71 has been linked with cases of acute flaccid paralysis (AFP), AFP surveillance is one strategy for documenting its possible circulation in the country. To expand current knowledge on EV-A71, molecular epidemiologic analysis and genetic characterization of EV-A71 isolates were performed in this study. METHODS: A retrospective study was performed to identify and characterize nonpolio enteroviruses (NPEVs) associated with AFP in the Philippines, and nine samples were found to be EV-A71-positive. Following characterization of these EV-A71 isolates, the complete viral protein 1 (VP1) gene was targeted for phylogenetic analysis. RESULTS: Nine EV-A71 isolates detected in 2000 (n = 2), 2002 (n = 4), 2005 (n = 2), and 2010 (n = 1) were characterized using molecular methods. Genomic regions spanning the complete VP1 region were amplified and sequenced using specific primers. Phylogenetic analysis of the full-length VP1 region identified all nine EV-A71 Philippine isolates as belonging to the genogroup C lineage, specifically the C2 cluster. The result indicated a genetic linkage with several strains isolated in Japan and Taiwan, suggesting that strains in the C2 cluster identified in the Asia-Pacific region were circulating in the Philippines. CONCLUSION: The study presents the genetic analysis of EV-A71 in the Philippines. Despite some limitations, the study provides additional genetic data on the circulating EV-A71 strains in the Asia-Pacific region, in which information on EV-A71 molecular epidemiology is incomplete. Considering that EV-A71 has a significant public health impact in the region, knowledge of its circulation in each country is important, especially for formulating vaccines covering a wide variety of strains.

  28. 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.

  29. Detection of Subgenotype IA and IIIA Hepatitis A Viruses in Rivers Flowing through Metro Manila, the Philippines. Peer-reviewed

    Huimin Bai, Tomoyuki Shiota, Sayaka Yoshizaki, Mariko Saito-Obata, Fedelino F Malbas Jr, Socorro P Lupisan, Hitoshi Oshitani, Naokazu Takeda, Masamichi Muramatsu, Takaji Wakita, Koji Ishii, Tian-Cheng Li

    Japanese journal of infectious diseases　72　(1)　53-55　2019/01/23

    DOI： 10.7883/yoken.JJID.2018.148 　

    ISSN： 1344-6304

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    Hepatitis A virus (HAV) is a common infectious etiology of acute hepatitis worldwide. The Philippines remains highly endemic for hepatitis A, but there is still a lack of information about HAV in the country. To evaluate the HAV contamination in environmental water in the Philippines, we conducted the detection and genetic analyses of HAV RNA in samples from river water. Twelve water samples were collected at 6 sampling sites of 3 rivers in Metro Manila, in both the dry and wet seasons in 2012 and 2013. The HAV RNA was detected in all the 6 samples collected in the dry season, and in one sample from the wet season. Phylogenetic analysis confirmed that the HAV strains detected in the river water included multiple sequences belonging to subgenotypes IA and IIIA. This indicates that at least 2 genotypes of the HAV strains are circulating in the environment in the Philippines, posing a risk of HAV infection to not only residents, but also tourists, especially in the dry season.

  30. 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.

  31. 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.

  32. 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.

  33. Comprehensive etiological and epidemiological study on acute respiratory infections in children: Providing evidence for the prevention and control of childhood plneumonia in the Philippines Peer-reviewed

    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

  34. 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.

  35. Bordetella pertussis infection in children with severe pneumonia, Philippines, 2012-2015. International-journal Peer-reviewed

    Alexander Sadiasa, Mariko Saito-Obata, Clyde Dapat

    Vaccine　35　(7)　993-996　2017/02/15

    DOI： 10.1016/j.vaccine.2016.11.087 　

    ISSN： 0264-410X

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    A case-comparison study was conducted based on an observational study of severe pneumonia among hospitalized children in the Philippines. The children, from 8days to 13years old and hospitalized with clinical diagnosis of severe or very severe pneumonia from August 2012 to February 2015, were recruited. Nasopharyngeal swabs were collected from 1152 cases and B. pertussis were detected from 34 cases by PCR. Pertussis-positive cases were more likely to have no fever, more than one week of coughing and breathing difficulty, decreased breathing sounds, and central cyanosis than pertussis- negative cases. The percentage of underweight was significantly higher in pertussis-positive cases than pertussis-negative cases. Pertussis-positive cases showed remarkably higher fatality rate than pertussis-negative cases. All of the fatal cases among pertussis-positive cases were less than 6months old. More attention should be given to protect young infants from pertussis.

  36. 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.

  37. Differences in viral load among human respiratory syncytial virus genotypes in hospitalized children with severe acute respiratory infections in the Philippines. International-journal Peer-reviewed

    Francois Marie Ngako Kadji, Michiko Okamoto, Yuki Furuse, Raita Tamaki, Akira Suzuki, Irene Lirio, Clyde Dapat, Rungnapa Malasao, Mariko Saito, Gay Anne Granada Pedrera-Rico, Veronica Tallo, Socorro Lupisan, Mayuko Saito, Hitoshi Oshitani

    Virology journal　13　113-113　2016/06/27

    DOI： 10.1186/s12985-016-0565-8 　

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    BACKGROUND: Human respiratory syncytial virus (HRSV) is a leading viral etiologic agent of pediatric lower respiratory infections, including bronchiolitis and pneumonia. Two antigenic subgroups, HRSV-A and B, each contain several genotypes. While viral load may vary among HRSV genotypes and affect the clinical course of disease, data are scarce regarding the actual differences among genotypes. Therefore, this study estimated and compared viral load among NA1 and ON1 genotypes of HRSV-A and BA9 of HRSV-B. ON1 is a newly emerged genotype with a 72-nucleotide duplication in the G gene as observed previously with BA genotypes in HRSV-B. FINDINGS: Children <5 years of age with an initial diagnosis of severe or very severe pneumonia at a hospital in the Philippines from September 2012 to December 2013 were enrolled. HRSV genotypes were determined and the viral load measured from nasopharyngeal swabs (NPS). The viral load of HRSV genotype NA1 were significantly higher than those of ON1 and BA9. Regression analysis showed that both genotype NA1 and younger age were significantly associated with high HRSV viral load. CONCLUSIONS: The viral load of NA1 was higher than that of ON1 and BA9 in NPS samples. HRSV genotypes may be associated with HRSV viral load. The reasons and clinical impacts of these differences in viral load among HRSV genotypes require further evaluation.

  38. 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.

  39. Molecular Characterization of Chikungunya Virus, Philippines, 2011-2013. International-journal Peer-reviewed

    Ava Kristy Sy, Mariko Saito-Obata, Inez Andrea Medado, Kentaro Tohma, Clyde Dapat, Edelwisa Segubre-Mercado, Amado Tandoc 3rd, Socorro Lupisan, Hitoshi Oshitani

    Emerging infectious diseases　22　(5)　887-90　2016/05

    DOI： 10.3201/eid2205.151268 　

    ISSN： 1080-6040

    eISSN： 1080-6059

  40. Molecular and mathematical modeling analyses of inter-island transmission of rabies into a previously rabies-free island in the Philippines. International-journal Peer-reviewed

    Kentaro Tohma, Mariko Saito, Catalino S Demetria, Daria L Manalo, Beatriz P Quiambao, Taro Kamigaki, Hitoshi Oshitani

    Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases　38　22-28　2016/03

    DOI： 10.1016/j.meegid.2015.12.001 　

    ISSN： 1567-1348

    eISSN： 1567-7257

  41. Molecular detection and characterization of sapovirus in hospitalized children with acute gastroenteritis in the Philippines. International-journal Peer-reviewed

    Xiaofang Liu, Dai Yamamoto, Mariko Saito, Toshifumi Imagawa, Adrianne Ablola, Amado O Tandoc 3rd, Edelwisa Segubre-Mercado, Socorro P Lupisan, Michiko Okamoto, Yuki Furuse, Mayuko Saito, Hitoshi Oshitani

    Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology　68　83-8　2015/07

    DOI： 10.1016/j.jcv.2015.05.001 　

    ISSN： 1386-6532

    eISSN： 1873-5967

  42. 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.

  43. Molecular epidemiology of Bordetella pertussis in the Philippines in 2012-2014. International-journal Peer-reviewed

    Salvacion Rosario L Galit, Nao Otsuka, Yuki Furuse, Daryl Joy V Almonia, Lydia T Sombrero, Rosario Z Capeding, Socorro P Lupisan, Mariko Saito, Hitoshi Oshitani, Yukihiro Hiramatsu, Keigo Shibayama, Kazunari Kamachi

    International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases　35　24-6　2015/06

    DOI： 10.1016/j.ijid.2015.04.001 　

    ISSN： 1201-9712

    eISSN： 1878-3511

  44. Isolation and characterization of influenza C viruses in the Philippines and Japan. International-journal 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)　847-58　2015/03

    DOI： 10.1128/JCM.02628-14 　

    ISSN： 0095-1137

    eISSN： 1098-660X

  45. Molecular epidemiology of enterovirus D68 from 2013 to 2014 in Philippines. International-journal 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)　1015-8　2015/03

    DOI： 10.1128/JCM.03362-14 　

    ISSN： 0095-1137

    eISSN： 1098-660X

  46. Outbreak of Henipavirus Infection, Philippines, 2014 Peer-reviewed

    Paola Katrina G. Ching, Vikki Carr de los Reyes, Maria Nemia Sucaldito, Enrique Tayag, Alah Baby Columna-Vingno, Fedelino F. Malbas, Gilbert C. Bolo, James J. Sejvar, Debbie Eagles, Geoffrey Playford, Erica Dueger, Yoshihiro Kaku, Shigeru Morikawa, Makoto Kuroda, Glenn A. Marsh, Sam McCullough, A. Ruth Foxwell

    EMERGING INFECTIOUS DISEASES　21　(2)　328-331　2015/02

    DOI： 10.3201/eid2102.141433 　

    ISSN： 1080-6040

    eISSN： 1080-6059

  47. Seroprevalence and molecular characteristics of hepatitis E virus in household-raised pig population in the Philippines. International-journal Peer-reviewed

    Xiaofang Liu, Mariko Saito, Yusuke Sayama, Ellie Suzuki, Fedelino F Malbas Jr, Hazel O Galang, Yuki Furuse, Mayuko Saito, Tiancheng Li, Akira Suzuki, Hitoshi Oshitani

    BMC veterinary research　11　11-11　2015/01/27

    DOI： 10.1186/s12917-015-0322-z 　

    ISSN： 1746-6148

  48. Influenza and other respiratory viruses detected by influenza-like illness surveillance in Leyte Island, the Philippines, 2010-2013. International-journal 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

    DOI： 10.1371/journal.pone.0123755 　

    ISSN： 1932-6203

  49. Molecular Characterization of Human Respiratory Syncytial Virus in the Philippines, 2012-2013. International-journal 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

    DOI： 10.1371/journal.pone.0142192 　

    ISSN： 1932-6203

  50. Phylogeographic analysis of rabies viruses in the Philippines. International-journal Peer-reviewed

    Kentaro Tohma, Mariko Saito, Taro Kamigaki, Laarni T Tuason, Catalino S Demetria, Jun Ryan C Orbina, Daria L Manalo, Mary E Miranda, Akira Noguchi, Satoshi Inoue, Akira Suzuki, Beatriz P Quiambao, Hitoshi Oshitani

    Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases　23　86-94　2014/04

    DOI： 10.1016/j.meegid.2014.01.026 　

    ISSN： 1567-1348

    eISSN： 1567-7257

  51. Molecular detection of hepatitis E virus in rivers in the Philippines. International-journal Peer-reviewed

    Tian-Cheng Li, Tingting Yang, Tomoyuki Shiota, Sayaka Yoshizaki, Hiromu Yoshida, Mariko Saito, Toshifumi Imagawa, Fidelino F Malbas, Socorro P Lupisan, Hitoshi Oshitani, Takaji Wakita, Koji Ishii

    The American journal of tropical medicine and hygiene　90　(4)　764-6　2014/04

    DOI： 10.4269/ajtmh.13-0562 　

    ISSN： 0002-9637

    eISSN： 1476-1645

  52. 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

  53. 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 3rd, Edelwisa Mercado, Lydia Sombrero, Remigio Olveda, Hitoshi Oshitani

    Japanese journal of infectious diseases　67　(2)　105-10　2014

    ISSN： 1344-6304

    eISSN： 1884-2836

  54. Genetic characterization of human respiratory syncytial virus detected in hospitalized children in the Philippines from 2008 to 2012. International-journal 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 : the official publication of the Pan American Society for Clinical Virology　57　(1)　59-65　2013/05

    DOI： 10.1016/j.jcv.2013.01.001 　

    ISSN： 1386-6532

  55. [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.

  56. Genetic diversity and geographic distribution of genetically distinct rabies viruses in the Philippines. International-journal Peer-reviewed

    Mariko Saito, Hitoshi Oshitani, Jun Ryan C Orbina, Kentaro Tohma, Alice S de Guzman, Taro Kamigaki, Catalino S Demetria, Daria L Manalo, Mary Elizabeth G Miranda, Akira Noguchi, Satoshi Inoue, Beatriz P Quiambao

    PLoS neglected tropical diseases　7　(4)　e2144　2013

    DOI： 10.1371/journal.pntd.0002144 　

    ISSN： 1935-2727

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    BACKGROUND: Rabies continues to be a major public health problem in the Philippines, where 200-300 human cases were reported annually between 2001 and 2011. Understanding the phylogeography of rabies viruses is important for establishing a more effective and feasible control strategy. METHODS: We performed a molecular analysis of rabies viruses in the Philippines using rabied animal brain samples. The samples were collected from 11 of 17 regions, which covered three island groups (Luzon, Visayas, and Mindanao). Partial nucleoprotein (N) gene sequencing was performed on 57 samples and complete glycoprotein (G) gene sequencing was performed on 235 samples collected between 2004 and 2010. RESULTS: The Philippine strains of rabies viruses were included in a distinct phylogenetic cluster, previously named Asian 2b, which appeared to have diverged from the Chinese strain named Asian 2a. The Philippine strains were further divided into three major clades, which were found exclusively in different island groups: clades L, V, and M in Luzon, Visayas, and Mindanao, respectively. Clade L was subdivided into nine subclades (L1-L9) and clade V was subdivided into two subclades (V1 and V2). With a few exceptions, most strains in each subclade were distributed in specific geographic areas. There were also four strains that were divided into two genogroups but were not classified into any of the three major clades, and all four strains were found in the island group of Luzon. CONCLUSION: We detected three major clades and two distinct genogroups of rabies viruses in the Philippines. Our data suggest that viruses of each clade and subclade evolved independently in each area without frequent introduction into other areas. An important implication of these data is that geographically targeted dog vaccination using the island group approach may effectively control rabies in the Philippines.

  57. Molecular evolution of enterovirus 68 detected in the Philippines. International-journal 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 3rd, Lydia Sombrero, Remigio Olveda, Hitoshi Oshitani

    PloS one　8　(9)　e74221　2013

    DOI： 10.1371/journal.pone.0074221 　

    ISSN： 1932-6203

  58. Respiratory viruses from hospitalized children with severe pneumonia in the Philippines. International-journal Peer-reviewed

    Akira Suzuki, Socorro Lupisan, Yuki Furuse, Naoko Fuji, Mariko Saito, Raita Tamaki, Hazel Galang, Lydia Sombrero, Melisa Mondoy, Rapunzel Aniceto, Remigio Olveda, Hitoshi Oshitani

    BMC infectious diseases　12　267-267　2012/10/23

    DOI： 10.1186/1471-2334-12-267 　

    ISSN： 1471-2334

  59. Genetic diversity and molecular characterization of enteroviruses from sewage-polluted urban and rural rivers in the Philippines. International-journal Peer-reviewed

    Lea Necitas G Apostol, Tomifumi Imagawa, Akira Suzuki, Yoshifumi Masago, Socorro Lupisan, Remigio Olveda, Mariko Saito, Tatsuo Omura, Hitoshi Oshitani

    Virus genes　45　(2)　207-17　2012/10

    DOI： 10.1007/s11262-012-0776-z 　

    ISSN： 0920-8569

    eISSN： 1572-994X

  60. A seroepidemiologic study of Reston ebolavirus in swine in the Philippines. International-journal Peer-reviewed

    Yusuke Sayama, Catalino Demetria, Mariko Saito, Rachel R Azul, Satoshi Taniguchi, Shuetsu Fukushi, Tomoki Yoshikawa, Itoe Iizuka, Tetsuya Mizutani, Ichiro Kurane, Fidelino F Malbas Jr, Socorro Lupisan, Davinio P Catbagan, Samuel B Animas, Rieldrin G Morales, Emelinda L Lopez, Karen Rose C Dazo, Magdalena S Cruz, Remigio Olveda, Masayuki Saijo, Hitoshi Oshitani, Shigeru Morikawa

    BMC veterinary research　8　82-82　2012/06/18

    DOI： 10.1186/1746-6148-8-82 　

    ISSN： 1746-6148

  61. マニラ首都圏における台風Ketsanaによる洪水域内環境水からの病原性レプトスピラの検出 Peer-reviewed

    沼澤聡, 真砂佳史, 齊藤麻理子, 山口諒, 押谷仁, 大村達夫

    土木学会論文集G（環境）　67　(7)　III_165-III_171　2011/11

  62. Interruption of the circulation of an indigenous measles genotype and the introduction of other genotypes after a mass vaccination campaign in the Philippines. International-journal Peer-reviewed

    Naoko Fuji, Akira Suzuki, Mariko Saito, Rex Centeno, Hazel Galang, Socorro Lupisan, Remigio Olveda, Hitoshi Oshitani

    Journal of medical virology　83　(8)　1424-7　2011/08

    DOI： 10.1002/jmv.22103 　

    ISSN： 0146-6615

  63. Enterovirus 68 among children with severe acute respiratory infection, the Philippines. International-journal Peer-reviewed

    Tadatsugu Imamura, Naoko Fuji, Akira Suzuki, Raita Tamaki, Mariko Saito, Rapunzel Aniceto, Hazel Galang, Lydia Sombrero, Soccoro Lupisan, Hitoshi Oshitani

    Emerging infectious diseases　17　(8)　1430-5　2011/08

    DOI： 10.3201/eid1708.101328 　

    ISSN： 1080-6040

  64. Detection of human rhinovirus C viral genome in blood among children with severe respiratory infections in the Philippines. International-journal Peer-reviewed

    Naoko Fuji, Akira Suzuki, Socorro Lupisan, Lydia Sombrero, Hazel Galang, Taro Kamigaki, Raita Tamaki, Mariko Saito, Rapunzel Aniceto, Remigio Olveda, Hitoshi Oshitani

    PloS one　6　(11)　e27247　2011

    DOI： 10.1371/journal.pone.0027247 　

    ISSN： 1932-6203

  65. 2008-2009年フィリピン・レイテ島タクロバンにおいて小児重症肺炎患者から検出されたRSウイルス

    大野 歩, 鈴木 陽, 藤 直子, 古瀬 祐気, 玉記 雷太, 齋藤 麻理子, 押谷 仁

    感染症学雑誌　84　(臨増)　290-290　2010/03

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

    eISSN： 1884-569X

  66. Evaluation of a dengue IgG indirect enzyme-linked immunosorbent assay and a Japanese encephalitis IgG indirect enzyme-linked immunosorbent assay for diagnosis of secondary dengue virus infection. International-journal Peer-reviewed

    Shingo Inoue, Maria T G Alonzo, Yae Kurosawa, Cynthia A Mapua, Joyce D Reyes, Efren M Dimaano, Maria Theresa P Alera, Mariko Saito, Kazunori Oishi, Futoshi Hasebe, Ronald R Matias, Filipinas F Natividad, Kouichi Morita

    Vector borne and zoonotic diseases (Larchmont, N.Y.)　10　(2)　143-50　2010/03

    DOI： 10.1089/vbz.2008.0153 　

    ISSN： 1530-3667

  67. フィリピン・レイテ島における小児重症肺炎の疫学調査

    鈴木 陽, 古瀬 祐気, 藤 直子, 大野 歩, 玉記 雷太, 齋藤 麻理子, 押谷 仁

    日本小児科学会雑誌　113　(12)　1876-1876　2009/12

    Publisher: (公社)日本小児科学会

    ISSN： 0001-6543

  68. Reassortment between Amantadine-Resistant and -Sensitive H1N1 Influenza A Viruses Generated an Amantadine-Sensitive Virus during the 2007-2008 Season Peer-reviewed

    Yuki Furuse, Akira Suzuki, Midori Shimizu, Makiko Kishi, Rumi Sawayama, Mariko Saito, Naoko Fuji, Nao Nukiwa, Hitoshi Oshitani

    JOURNAL OF INFECTIOUS DISEASES　200　(11)　1766-1773　2009/12

    DOI： 10.1086/647989 　

    ISSN： 0022-1899

  69. Increased phagocytosis of platelets from patients with secondary dengue virus infection by human macrophages. International-journal Peer-reviewed

    Shoko Honda, Mariko Saito, Efren M Dimaano, Philip A Morales, Maria T G Alonzo, Lady-Anne C Suarez, Natsuki Koike, Shingo Inoue, Atsushi Kumatori, Ronald R Matias, Filipinas F Natividad, Kazunori Oishi

    The American journal of tropical medicine and hygiene　80　(5)　841-5　2009/05

    ISSN： 0002-9637

    eISSN： 1476-1645

  70. Lack of efficacy of high-dose intravenous immunoglobulin treatment of severe thrombocytopenia in patients with secondary dengue virus infection. International-journal Peer-reviewed

    Efren M Dimaano, Mariko Saito, Shoko Honda, Edna A Miranda, Maria T G Alonzo, Myra D Valerio, Cynthia A Mapua, Shingo Inoue, Atsushi Kumaori, Ronald Matias, Filipinas F Natividad, Kazunori Oishi

    The American journal of tropical medicine and hygiene　77　(6)　1135-8　2007/12

    ISSN： 0002-9637

  71. Dengue illness: clinical features and pathogenesis. International-journal Peer-reviewed

    Kazunori Oishi, Mariko Saito, Cynthia A Mapua, Filipinas F Natividad

    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy　13　(3)　125-33　2007/06

    DOI： 10.1007/s10156-007-0516-9 　

    ISSN： 1341-321X

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    The incidence and geographical distribution of dengue has gradually increased during the past decade. This review is an update on dengue virus infections, based on our clinical and laboratory experiences in the Philippines and on other relevant literature. The differential diagnosis of this disease is discussed, especially for use by clinicians where dengue is not endemic. The complex pathogenesis of thrombocytopenia and increased vascular permeability in dengue illness is also discussed. Our recent data suggest that platelet-associated immunoglobulins involving anti-dengue virus activity play a pivotal role in the development of dengue hemorrhagic fever (DHF), as well as thrombocytopenia in secondary dengue virus infections. Further elucidation is needed on the involvement of platelet-associated immunoglobulins on the molecular mechanisms of thrombocytopenia and the increased vascular permeability.

  72. Strain-specific pulmonary defense achieved after repeated airway immunizations with non-typeable Haemophilus influenzae in a mouse model Peer-reviewed

    Jun Koyama, Kamruddin Ahmed, Jizi Zhao, Mariko Saito, Shozaburo Onizuko, Keita Oma, Kiwao Watanabe, Hiroshi Watanabe, Kazunori Oishi

    TOHOKU JOURNAL OF EXPERIMENTAL MEDICINE　211　(1)　63-74　2007/01

    ISSN： 0040-8727

    eISSN： 1349-3329

  73. Possible prevalence and transmission of acute respiratory tract infections caused by Streptococcus pneumoniae and Haemophilus influenzae among the internally displaced persons in tsunami disaster evacuation camps of Sri Lanka Peer-reviewed

    Hiroshi Watanabe, Ranjith Batuwanthudawe, Vasanthi Thevanesam, Chiharu Kaji, Liang Qin, Nobuyuki Nishikiori, Wakana Saito, Mariko Saito, Kiwao Watanabe, Kazunori Oishi, Nihal Abeysinghe, Osamu Kunii

    INTERNAL MEDICINE　46　(17)　1395-1402　2007

    DOI： 10.2169/internalmedicine.46.0149 　

    ISSN： 0918-2918

    eISSN： 1349-7235

  74. Dengue and other febrile illnesses among children in the Philippines

    Kazunori Oishi, Cynthia A. Mapua, Celia C. Carlos, Maria T.D.D. Cinco-Abanes, Mariko Saito, Shingo Inoue, Kouichi Morita, Filipinas F. Natividad

    Dengue Bulletin　30　26-34　2006/12

    ISSN： 1020-895X

  75. Association of increased platelet-associated immunogloblins with thrombocytopenia and the severity of disease in secondary dengue virus infections Peer-reviewed

    Mariko Saito, Shingo Inoue, Efren M. Dimaano, Maria T. Alera, Atsushi Kumatori, Kazuhiko Moji, Ronald R. Matias, Kouichi Morita, Filipinas F. Natividad, Kazunori Oishi

    AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE　73　(6)　75-75　2005/12

    ISSN： 0002-9637

  76. Association of increased platelet-associated immunoglobulins with thrombocytopenia and the severity of disease in secondary dengue virus infections Peer-reviewed

    M Saito, K Oishi, S Inoue, EM Dimaano, MTP Alera, AMP Robles, BD Estrella, A Kumatori, K Moji, MT Alonzo, CC Buerano, RR Matias, K Morita, FF Natividad, T Nagatake

    CLINICAL AND EXPERIMENTAL IMMUNOLOGY　138　(2)　299-303　2004/11

    DOI： 10.1111/j.1365-2249.2004.02626.x 　

    ISSN： 0009-9104

  77. Association of dengue virus type-specific IgG on platelets is specific for the acute phase in an imported Japanese patient with secondary dengue 2 virus infection.

    K. Oishi, S. Inoue, T. Kuramoto, S. Onizuka, M. Saito, F. Hasebe, K. Morita, T. Nagatake

    Tropical Medicine and Health　31　(4)　223-225　2003/04

    Publisher: Japanese Society of Tropical Medicine

    DOI： 10.2149/tmh1973.31.223 　

    ISSN： 0304-2146

    More details Close

    The mechanism of thrombocytopenia in dengue virus infection remains unknown. We report herein an imported case of a 21-year-old male Japanese with dengue fever caused by secondary dengue 2 virus infection. The thrombocytopenia detected around the day of defervescence was associated with an increased level of platelet-associated IgG (PAIgG). The eluate from the platelets during the acute phase of this case contained an increased activity of anti-dengue virus 2 IgG, while the eluate from platelets during the convalescent phase contained a low level of anti-dengue 2 IgG. These findings suggest the transient formation of PAIgG involving anti-dengue 2 virus IgG during the acute phase of secondary dengue 2 virus infection.

Show all ︎Show first 5

Misc. 41

  1. フィリピンにおける狂犬病迅速診断キットの有用性評価中間解析(ヒト・動物)

    齊藤 信夫, 鈴木 基, 西園 晃, 君付 和範, 山田 健太郎, 齊藤 麻理子[小畑], 朴 天鎬, 井上 智, Quiambao Beatriz

    感染症学雑誌　94　(臨増)　322-322　2020/03

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  2. フィリピンにおける狂犬病迅速診断キットの有用性評価中間解析(ヒト・動物)

    齊藤 信夫, 鈴木 基, 西園 晃, 君付 和範, 山田 健太郎, 齊藤 麻理子[小畑], 朴 天鎬, 井上 智, Quiambao Beatriz

    感染症学雑誌　94　(臨増)　322-322　2020/03

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  3. 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

  4. 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

  5. 【「感染症研究国際ネットワーク推進プログラム(J-GRID)」10年のあゆみ】 東北大学とフィリピン熱帯医学研究所のパートナーシップ

    齊藤 麻理子

    最新医学　70　(4)　754-760　2015/04

    Publisher: (株)最新医学社

    ISSN： 0370-8241

  6. フィリピン共和国タクロバン市において下痢症患者および河川水中から検出されたロタウイルスの遺伝子型解析

    今川稔文, 山本大, 齋藤繭子, GAYLON Ruel, 齋藤麻理子, 真砂佳史, ANGULO Rhodora, HIJADA Jonathan R, MERCADO Edelwisa S, LUPISAN Socorro P, 押谷仁

    日本ウイルス学会学術集会プログラム・抄録集　62nd　269　2014/10/31

  7. Research activities and responding to typhoon Haiyan (Yolanda): Tohoku-RITM collaborating research center in the Philippines

    Mariko Saito, Mayuko Saito, Tadatsugu Imamura, Taro Kamigaki, Socorro P. Lupisan, Hitoshi Oshitani

    Journal of Disaster Research　9　(5)　823-827　2014/10/01

    Publisher: Fuji Technology Press

    DOI： 10.20965/jdr.2014.p0823 　

    ISSN： 1883-8030 1881-2473

  8. 【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

  9. 【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

  10. Characterization of Coxsackievirus A20 as the donor strain at the nonstructural region of the recombinant type 1 circulating vaccine-derived polioviruses in the Philippines

    L. N. Apostol, H. Shimizu, A. Naeem, A. Suzuki, S. Lupisan, M. Saito, R. Olveda, H. Oshitani

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　16　E68-E68　2012/06

    DOI： 10.1016/j.ijid.2012.05.168 　

    ISSN： 1201-9712

  11. マニラ首都圏における台風Ketsanaによる洪水域内環境水からの病原性レプトスピラの検出

    沼澤聡, 真砂佳史, 齊藤麻理子, 山口諒, 押谷仁, 大村達夫

    環境工学研究論文集　48　III.165-III.171　2011/11/25

    ISSN： 1341-5115

  12. Interruption of the circulation of an indigenous measles genotype and the introduction of other genotypes after a mass vaccination campaign in the Philippines. (vol 83, pg 1424, 2011)

    N. Fuji, A. Suzuki, M. Saito, R. Centeno, H. Galang, S. Lupisan, R. Olveda, Hitoshi Oshitani

    JOURNAL OF MEDICAL VIROLOGY　83　(10)　1866-1866　2011/10

    DOI： 10.1002/jmv.22212 　

    ISSN： 0146-6615

  13. 台風Ketsanaによる洪水試料からの病原性レプトスピラの検出

    沼澤聡, 真砂佳史, 齊藤麻理子, 山口諒, 押谷仁, 大村達夫

    土木学会年次学術講演会講演概要集(CD-ROM)　66th　ROMBUNNO.VII-014　2011/08/05

  14. Molecular epidemiology of rhinoviruses among children diagnosed as severe pneumonia in the Philippines

    N. Fuji, A. Suzuki, S. Lupisan, R. Tamaki, M. Saito, A. De Leon, R. Olveda, H. Oshitani

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　14　E472-E472　2010/03

    DOI： 10.1016/j.ijid.2010.02.667 　

    ISSN： 1201-9712

  15. Etiology of childhood pneumonia in Tacloban, the Philippines

    A. Suzuki, S. Lupisan, N. Fuji, A. Ohno, Y. Furuse, R. Tamaki, M. Saito, H. Oreste, M. Mondoy, L. Sombrero, A. De Leon, R. Olveda, H. Oshitani

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　14　E27-E27　2010/03

    DOI： 10.1016/j.ijid.2010.02.1547 　

    ISSN： 1201-9712

  16. Detection waterborne diseases associated viruses in the river water Metro Manila and Bulacan, the Philippines

    T. Imagawa, A. Suzuki, M. Saito, Y. Masago, C. Okumura, S. Lupisan, R. Olveda, T. Omura, H. Oshitani

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　14　E63-E63　2010/03

    DOI： 10.1016/j.ijid.2010.02.1628 　

    ISSN： 1201-9712

  17. 小児インフルエンザ罹患者の便からのインフルエンザウイルスの検出

    鈴木 陽, 齊藤 麻理子, 藤 直子, 清水 みどり, 押谷 仁, 阿部 修一, 板野 正敬, 井上 重夫, 遠藤 晃彦, 加納 一毅, 萱場 潤, 嘉山 益子, 川村 和久, 関 信夫, 田山 利幸, 速水 俊三, 松本 文子, 目時 規公也, 師 保之, 八木 恒夫, 山本 克哉, 吉田 眞

    日本小児科学会雑誌　113　(1)　155-155　2009/01

    Publisher: (公社)日本小児科学会

    ISSN： 0001-6543

  18. Emergence of New Genotypes of Measles Virus in the Philippines After a Mass Vaccination

    N. Fuji, A. Suzuki, T. Kamigaki, M. Saito, Y. Furuse, E. Miranda, S. Lupisan, R. Olveda, H. Oshitani

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　12　E100-E100　2008/12

    DOI： 10.1016/j.ijid.2008.05.250 　

    ISSN： 1201-9712

  19. Seasonality and Phylogenic Analysis of Influenzavirus in Philippines, 2006-2007

    H. Galang, A. Suzuki, Y. Furuse, N. Fuji, M. Saito, T. Kamigaki, S. Lupisan, H. Oshitani, R. Olveda

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　12　E101-E101　2008/12

    DOI： 10.1016/j.ijid.2008.05.252 　

    ISSN： 1201-9712

  20. Genetic Variation and Prevalence of Amantadine-Resistant Influenza A (H3N2) Viruses in Two Consecutive Seasons in Japan and the Philippines

    Y. Furuse, A. Suzuki, T. Kamigaki, M. Saito, N. Fuji, H. Galang, S. Lupisan, R. Olveda, H. Oshitani

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　12　E102-E102　2008/12

    DOI： 10.1016/j.ijid.2008.05.254 　

    ISSN： 1201-9712

  21. Review of Epidemiological Risk Factors of Measles Outbreak in Displaced Population

    K. Kouadio, T. Kamigaki, M. Saito, A. Suzuki, H. Oshitani

    INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES　12　E103-E103　2008/12

    DOI： 10.1016/j.ijid.2008.05.257 　

    ISSN： 1201-9712

  22. フィリピンにおける麻疹マスワクチンキャンペーン後の流行株のシフト

    鈴木 陽, 藤 直子, 古瀬 祐気, 齊藤 麻理子, 神垣 太郎, 押谷 仁

    感染症学雑誌　82　(6)　678-679　2008/11

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  23. 気候変動と感染症・疾病リスクの関連性 (特集 地球を蝕む気候変動)

    齊藤 麻理子, 押谷 仁

    都市問題　99　(9)　28-34　2008/09

    Publisher: 東京市政調査会

    ISSN： 0387-3382

  24. 感染症における皮膚病変 デングウイルス感染症の皮膚所見

    大石 和徳, 齊藤 麻理子

    化学療法の領域　24　(10)　1425-1430　2008/09

    Publisher: (株)医薬ジャーナル社

    ISSN： 0913-2384

  25. デングウイルス二次感染症におけるマクロファージによる血小板貪食クリアランスの亢進

    本田 章子, 齊藤 麻理子, 森本 浩之輔, 有吉 紅也, 大石 和徳

    感染症学雑誌　82　(3)　271-272　2008/05

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  26. フィリピンにおける麻疹マスワクチンキャンペーン後の流行株のシフト

    鈴木 陽, 藤 直子, 古瀬 祐気, 齊藤 麻理子, 神垣 太郎, 押谷 仁

    感染症学雑誌　82　(臨増)　325-325　2008/03

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  27. Inefficacy of the treatment with a high dose of intravenous immunoglobulin on severe thrombocytopenia in patients with secondary dengue virus infection

    Kazunori Oishi, Efren Dimaano, Mariko Saito, Filipinas Natividad

    AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE　77　(5)　35-35　2007/11

    ISSN： 0002-9637

  28. スマトラ沖地震・津波後のスリランカ避難キャンプにおける肺炎球菌,インフルエンザ菌による呼吸器感染症の流行と伝播の可能性

    渡辺 浩, 齋藤 若菜, 齊藤 麻理子, 加地 千春, 渡辺 貴和雄, 大石 和徳, 有吉 紅也, 錦織 信幸, 國井 修, Thevanesam Vasanthi, Batuwanthudawe Ranjith

    感染症学雑誌　80　(3)　309-309　2006/05

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  29. デングウイルス二次感染症における血小板減少機序の解明

    齊藤 麻理子

    Tropical Medicine and Health　33　(Suppl.)　18-18　2005/09

    Publisher: 日本熱帯医学会

    ISSN： 1348-8945

    eISSN： 1349-4147

  30. スマトラ沖地震津波後のスリランカの避難キャンプにおける肺炎球菌,インフルエンザ菌による呼吸器感染症の流行

    渡辺 浩, 齋藤 若奈, 齊藤 麻理子, 加地 千春, 渡辺 貴和雄, 大石 和徳, 錦織 信幸, 國井 修

    Tropical Medicine and Health　33　(Suppl.)　64-64　2005/09

    Publisher: 日本熱帯医学会

    ISSN： 1348-8945

    eISSN： 1349-4147

  31. デングウイルス二次感染症における液性因子の検討

    齊藤 麻理子, 本田 章子, 大石 和徳

    感染症学雑誌　79　(8)　586-587　2005/08

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  32. デングウイルス二次感染症における液性因子の検討

    齊藤 麻理子, 本田 章子, 大石 和徳

    感染症学雑誌　79　(臨増)　147-147　2005/03

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  33. デング二次感染症の重症化とPAIgM

    齊藤 麻理子, 本田 章子, 大石 和徳, 永武 毅, 松本 奈月, 井上 真吾, 森田 公一

    感染症学雑誌　79　(3)　215-216　2005/03

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  34. Reviewと研究 急性デングウイルス二次感染症においてPAIgG,PAIgMの増加は血小板減少機序および重症度と相関する

    大石 和徳, 斉藤 麻理子

    Virus report　1　(1)　74-80　2004/11

    Publisher: 医薬ジャーナル社

    ISSN： 1349-6956

  35. 熱帯現地で学ぶ臨床熱帯医学 デング重症化機序の解明を目指して

    齊藤 麻理子, 大石 和徳

    Tropical Medicine and Health　32　(Suppl.)　32-32　2004/09

    Publisher: 日本熱帯医学会

    ISSN： 1348-8945

    eISSN： 1349-4147

  36. 最近のフィリピン・メトロマニラにおける小児デングの臨床像

    本田 章子, 大石 和徳, 齊藤 麻理子, 永武 毅, 井上 真吾, 森田 公一, Matias RR, Alera TP, Dimaano EM, Natividad FF

    感染症学雑誌　78　(8)　784-784　2004/08

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  37. デング二次感染症におけるPAIgG,PAIgMの臨床的意義

    齊藤 麻理子, 大石 和徳, 本田 章子, 永武 毅, 井上 真吾, 森田 公一, Matias RR, Natividad FF, Alera TP, Dimaano EM

    感染症学雑誌　78　(7)　671-671　2004/07

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  38. デングウイルス感染症におけるPlatelet-associated IgG,IgMの臨床的意義

    齊藤 麻理子, 大石 和徳, 井上 真吾, 本田 章子, 長谷部 太, 熊取 厚志, 森田 公一, 永武 毅

    日本熱帯医学会雑誌　31　(増刊(国際保健医18増))　290-290　2003/10

    Publisher: 日本熱帯医学会

    ISSN： 0304-2146

  39. 最近のフィリピン・メトロマニラにおける小児デングの臨床病態研究

    本田 章子, 大石 和徳, 井上 真吾, 齊藤 麻理子, 長谷部 太, 森田 公一, 永武 毅

    日本熱帯医学会雑誌　31　(増刊(国際保健医18増))　291-291　2003/10

    Publisher: 日本熱帯医学会

    ISSN： 0304-2146

  40. Burkholderia.Pseudomallei培養上清中の肺上皮細胞におけるアポトーシス誘導因子

    齊藤 麻理子, 吉嶺 裕之, 大石 和徳, 永武 毅, 和田 昭裕, 平山 壽哉, Intarapoka Benjamas, 松島 綱治

    感染症学雑誌　76　(9)　768-769　2002/09

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

  41. Burkholderia.Pseudomallei培養上清中の肺上皮細胞におけるアポトーシス誘導因子

    齊藤 麻理子, 吉嶺 裕之, 大石 和徳, 永武 毅

    感染症学雑誌　76　(臨増)　180-180　2002/03

    Publisher: (一社)日本感染症学会

    ISSN： 0387-5911

Show all ︎Show first 5