Isolation/detection of influenza virus in Japan, week 36/2012-week 7/2013 (as of February 21, 2013)

In Japan, prefectural and municipal public health institutes (PHIs) report isolation/detection of infectious agents from specimens collected by sentinel clinics and hospitals under the National Epidemiological Surveillance of Infectious Diseases, other medical institutions and health centers (Reference figure).

Figure 1. Weekly reports of influenza virus isolation/detection, week 36/2012-week 8/2013

Figure 2. Isolation/detection of influenza virus by prefecture, week 36/2012-week 8/2013

Figure 3. Weekly isolation/detection of influenza virus by prefecture, week 3-week 7/2013

From the beginning of 2012/13 season (from week 36/September of 2012 to week 35/August of 2013), isolations/detections of influenza virus AH3 was dominantly reported and the report increased from week 47 (November 19-25). After the New Year holidays, the report increased again from week 2/2013 (Fig. 1).

In the 2012/13 season, from week 36 (September 3-9, 2012) to week 8 (February18-24, 2013), isolations/detections of AH1pdm09 from 55 cases in 24 prefectures, AH3 from 2,422 cases in 47 prefectures, B/Victoria lineage from 82 cases in 15 prefectures, B/Yamagata lineage from 120 cases in 26 prefectures and B/lineage not determined from 43 cases in 18 prefectures were reported (Fig. 2).

From week 3 (January 14-20) to week 7 (February 11-17) of 2013 (as of February 21, 2013)

During five weeks from week 3 to week 7 of 2013, isolations/detections of AH1pdm09 from 17 cases in 11 prefectures, AH3 from 1,201 cases in 42 prefectures, B/Victoria lineage from 48 cases in 11 prefectures, B/Yamagata lineage from93 cases in 24 prefectures and B/lineage not determined from 28 cases in 13 prefectures were reported (Fig. 3).

[Reference figure] Weekly cases of influenza and isolation/detection of influenza viruses from week 36 of 2008 to week 41 of 2011

Isolation/detection of influenza virus in Japan, from week 36 (September 5-11) of 2011 to week 25 (June 18-24) of 2011 (as of July 19, 2012)

Isolation/detection of influenza virus in Japan, from week 36 (September 6-12) of 2010 to week 19 (May 9-15) of 2011 (as of September 6, 2011)

Isolation/detection of influenza virus in Japan, from week 19 (May 4-10) of 2009 to week 19 (May 10-16) of 2010 (as of May 13, 2010)

Infectious Agents Surveillance Report, Infectious Disease Surveillance Center,
National Institute of Infectious Diseases

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