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HOME Activities International Health

1.Research Summary

In the field of International health, we focus on molecular epidemiological analysis of viruses that cause respiratory infections such as influenza viruses and respiratory syncytial (RS) viruses and we monitor for the emergence of drug-resistant viruses. In recent years, we have been conducting spatial analyses of patterns of virus transmission and accumulation using a geographic information system (GIS) and endeavoring to apply the GIS method to the field of social epidemiology.
We provide detailed information about our research outlines and results on our website.

2.Research Group

  • Molecular epidemiology of infectious diseases Group
  • GIS Group

3-1.Molecular epidemiology of infectious diseases Group

Research subject

  • Molecular epidemiology of influenza viruses in Japan and other countries
  • Drug-resistant influenza in Japan and other countries
  • Molecular epidemiology of RS virus in Japan and other countries

3-2.GIS Group

Research subject

  • Expansion and accumulation patterns of infectious diseases
  • Spatial analysis of medical resources and demands (collaborative research)
  • Geographic analysis of radioactive contamination in Fukushima prefecture (international collaborative research)
  • Geographic study on disease properties from the viewpoint of medical costs
  • Factors involved in effects of specific health check-ups
  • Effects of social capital on geriatric health

4.Research Results

[Area] International health (molecular epidemiology)

[Research subject 1] Comparison of influenza virus strains isolated in Myanmar from 2007 to 2010 with epidemic strains in Asian countries using genetic analysis

[Description]
We have been conducting molecular epidemiological studies and antiviral resistance studies on influenza viruses in collaboration with on-site researchers based in two cities Yangon and Nay Pyi Daw in Myanmar since 2004. We found that new influenza virus strains emerge in Myanmar every year earlier than in the influenza season in Japan through the molecular epidemiological studies in Myanmar. We have confirmed that Myanmar is an important country for early identification of epidemic strains in China, where new influenza strains emerge before circulating worldwide to cause seasonal epidemics. In addition, we had already isolated the A/H3N2 strains in Myanmar in 2008, which were circulated in 2008-2009 influenza season in Japan (6 months earlier than the isolates in Japan). Thus, we have revealed that Myanmar is one of important countries for the future selection of vaccine strains.
(DapatC. et al. 2009)

[Photographs]

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The A/H3N2 strains which were circulated in 2008-2009 influenza season in Japan, had been isolated in Myanmar in 2008 (6 months earlier than in Japan).In addition, the A/H3N2 Myanmar isolates in 2009 showed different antigenicity as compared to circulated A/H3N2 strains in the last season, and also were similar to A/Perth/6/2009 strain, a vaccine strain for the 2009-2010 season. These results highlight the importance of influenza virus surveillance in Myanmar.

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[Area] International Health (Clinical epidemiology)

[Research subject 2] Estimation of seasonal influenza vaccine effectiveness among children in Japan

[Description]
We estimated the influenza vaccine effectiveness for children 1-11 years of age using rapid test kits in Isahaya City, involving 28,884 children-years, over two consecutive influenza seasons(2011-12 and 2012-13) from an influenza registration program organized by the Isahaya Medical Association for all pediatric facilities in the city. The trivalent influenza vaccine has a significant protective effect for children 1-11 years of age against influenza A and B infection in the 2011-12 season and against influenza A infection in the 2012-13 season in a community in Japan.
iSuzuki et al. 2014j

[Photographs]

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[Area] International Health (Molecular epidemiology)

[Research subject 3] Spatial analysis of Influenza

[Description]
In cooperation with the Isahaya City Medical Association in Nagasaki Prefecture, we collect data from all patients who visit cooperating medical facilities for influenza and perform an epidemiological analysis of these patients. In winter, when influenza is prevalent, we create a map of the incidence rate of influenza based on weekly information about patients with influenza and provide it to the Medical Association. Meanwhile, we showed a relationship between the influenza epidemic peak and the spatial distribution of influenza in Japan using Weighted Standard Distance, an indicator for spatial analysis, based on data from stationary influenza observation facilities nationwide under the scheme of the National Infectious Disease Surveillance Center.
iShobugawa et al.j

[Photographs]

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Above Figure: Left panel shows clustered outbreaks in a limited region with small WSD circles and that on the right shows nationwide dispersed outbreaks with large circles. This study demonstrated a relationship between circle sizes and epidemic peak timings.

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