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 45-week49 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 36-50 of 2012 (week of specimen collection), detections of norovirus genogroup (G) II from 333 cases in 25 of 47 prefectures (including GII/4 from 71 cases, GII/6 from 6 cases, GII/13 from 4 cases, GII/3 and GII/7 from one case each), norovirus GI from 8 cases in 3 prefectures (including GI/3 from 2 cases), norovirus genogroup unknown from 12 cases in 4 prefectures, sapovirus from 22 cases in 9 prefectures (including GI from 6 cases and GII from 2 cases) (Figure 2), and astrovirus from 2 cases in 2 prefectures (including type 8 from one case) were reported.

  During five weeks from week 45 (November 5-11) to week 49 (December 3-9) of 2012, detections of norovirus from 271 cases in 20 prefectures (Figure 3), sapovirus from 13 cases in 6 prefectures and astrovirus from one case in Niigata Prefecture 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), 63 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 14 prefectures during weeks 36-49 of 2012 (onset week of outbreak).  From 17 of these outbreaks, norovirus GII/4 was detected [see fig. 1, fig. 2 and fig. 3 in reference (text in Japanese)], GII/2 and GI/3 from one each.

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