In Japan, prefectural and municipal public health institutes (PHIs) report 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.
  From gastroenteritis cases, norovirus and other viruses (sapovirus, rotavirus, astrovirus etc.) are detected.

*Data for current and previous weeks will be updated by additional reports.

Figure 1. Weekly reports of norovirus, sapovirus and rotavirus detection, 2012/13 season

Figure 2. Detection of norovirus, sapovirus and rotavirus by prefecture, 2012/13 season

Figure 3. Weekly detection of norovirus, sapovirus and rotavirus by prefecture, week 47-week 51 of 2012

  From week 36 (September 3-9) of 2012, the beginning of 2012/13 season, reports of norovirus detection continued and started to increase from week 44 (October 29-November 4) of 2012 (Figure 1).

  Based on the Individual Case Report, during weeks 36-51 of 2012 (week of specimen collection), detections of norovirus genogroup (G) II from 758 cases in 32 of 47 prefectures (including GII/4 from 173 cases, GII/6 from 7 cases, GII/13 from 7 cases, GII/2  from 2 cases, GII/3 and GII/7 from one case each), norovirus GI from 19 cases in 6 prefectures (including GI/3 from 2 cases and GI/4 from one case), norovirus genogroup unknown from 26 cases in 4 prefectures, sapovirus from 33 cases in 9 prefectures (including GI from 9 cases and GII from 2 cases), group A rotavirus from 2 cases in 2 prefectures (Figure 2), and astrovirus from 6 cases in 4 prefectures (including type 8 from 2 cases) were reported.

  During five weeks from week 47 (November 19-25) to week 51 (December 17-23) of 2012, detections of norovirus from 494 cases in 27 prefectures (Figure 3), sapovirus from 18 cases in 9 prefectures, group A rotavirus from one case in Kanagawa Prefecture and astrovirus from 3 cases in 2 prefectures were reported.

  Based on the Outbreak Summary Report (including food poisoning, food-related health complaints, and gastroenteritis with person-to-person infection or those with unknown transmission routes), 123 outbreak of norovirus gastroenteritis occurred at restaurants and banquet hall, nursery school, kindergarten, elementary school, junior high school, high school, elderly care facility, nursing care facility, hospital, hotel, etc. in 17 prefectures during weeks 36-51 of 2012 (onset week of outbreak).  From 97 of these outbreaks, norovirus GII was detected including GII/4 from 29 outbreaks [see fig. 1, fig. 2 and fig. 3 in reference (text in Japanese)], GII/4+GII/6, GII/2, GII/5 and GII/6 from one each, and norovirus GI was detected from 4 outbreaks including GI/6 from 2 outbreaks and GI/3 from one.

Link to Detection of norovirus GII/4 2012 variant in Japan (National Institute of Health Sciences)

Detection of gastroenteritis viruses in Japan, 2011/12 season (as of November 8, 2012)

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