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 7-week 11 of 2013
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, and peaked in week 48-50 of 2012 and decreased thereafter. From week 1 of 2013, reports of group A rotavirus detection continued and started to increase (Figure 1).
Based on the Individual Case Report, during week 36 of 2012-week 11 of 2013 (week of specimen collection), detections of norovirus genogroup (G) II from 1,883 cases in 43 of 47 prefectures (including GII/4 from 494 cases, GII/13 from 22 cases, GII/2 from 10 cases, GII/6 from 7 cases, GII/3 and GII/7 from 4 cases each and GII14 from one case), norovirus GI from 45 cases in 16 prefectures (including GI/6 from 4 cases, GI/3 from 2 cases, GI/4 and GI/11 and GI/13 from one each), norovirus genogroup unknown from 38 cases in 4 prefectures, sapovirus from 124 cases in 26 prefectures (including GI from 44 cases, GII from 9 cases and GIV from one case), group A rotavirus from 100 cases in 19 prefectures (including G1 from 26 cases, G3 and G9 from 3 cases each, G2 from 2 cases) (Figure 2), and astrovirus from 17 cases in 7 prefectures (including type 8 from 4 cases) were reported.
During five weeks from week 7 (February11-17) to week 11 (March 11-17) of 2013, detections of norovirus from 51 cases in 12 prefectures (Figure 3), sapovirus from 34 cases in 10 prefectures, group A rotavirus from 34 cases in 10 prefectures and astrovirus from one case in Niigata Prefecture was 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), 384 outbreaks of norovirus gastroenteritis occurred at restaurants and banquet hall, business olace, nursery school, kindergarten, elementary school, junior high school, high school, elderly care facility, nursing care facility, hospital, hotel, etc. in 27 prefectures during week 36 of 2012 to week 11 of 2013 (onset week of outbreak). From 329 of these outbreaks, norovirus GII was detected including GII/4 from 135 outbreaks [see fig. 1, fig. 2 and fig. 3 in reference (text in Japanese)], GII/2 from 8 outbreaks, GII/13 from 3 outbreaks, GII/6 from 2 outbreaks, GII/4+GII/6 and GII/5 from one each, and norovirus GI was detected from 11 outbreaks including GI/6 from 6 outbreaks and GI/3 from one outbreak. In addition, norovirus GI and GII were detected from 9 outbreaks including GI/1+GII/4, GI/4+GII/13, GI/6+GII/4+GII/11 and GI/6+GI/7+GI/13+GII/2+GII/4+GII/NT from one each.
On the other hand, group A rotavirus was detected from 2 outbreaks (including G1 and G2 from one each), sapovirus from 11 outbreaks (including GI from 8 outbreaks and GII from one), and group A rotavirus G1 and sapovirus GI 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