| At the beginning of 2011/12 season (week 36 of 2011), an outbreak of gastroenteritis occurred in a kindergarten in Osaka Prefecture and norovirus genogroup (G) I/4 was detected. After week 39, detection of norovirus GII from sporadic cases and outbreak cases increased and peaked in week 50.From week 2 to week 3 of 2012, detection of norovirus GII increased again and decreased after week 4. Detection of group A rotavirus gradually increased after wee k4. From week 36 of 2011 to week 19 of 2012, detection of norovirus GI from 178 cases in 22 of 47 prefectures (including GI/4 from 48 cases, GI/14 from 13 cases, GI/8 from 12 cases, GI/1 from 5 cases, GI/3 from 5 cases, GI/7 from 3 cases, GI/2 from 2 cases, GI/6 from one case amd GI/13 from one case), norovirus GII from 1,846 cases in 45 prefectures (including GII/4 from 402 cases, GII/2 from 78 cases, GII/13 from 29 cases, GII/12 from 28 cases, GII/6 from 22 cases, GII/3 from 19 cases, GII/7 from 4 cases, GII/5 from 3 cases and GII/14 from one case), sapovirus from 136 cases in 28 prefectures (including GI from 51 cases, GII from 8 cases and GIV from one case), group A rotavirus from 313 cases in 28 prefectures (including G1 from 63 cases, G3 from 30 cases, G2 from 10 cases and G9 from 9 cases), group C rotavirus from 5 cases in Niigata Prefecture, and astrovirus from 14 case in 7 prefectures (including type 1 from 3 cases and type 4 from one case) were reported. |
