2003 Volume 20 Issue 4 Pages 203-209
We investigated the characteristics of 15 gastroenteritis outbreaks due to viruses occurring in the 1999/2000, 2000/2001 and 2001/2002 cold seasons. Norovirus was identified in 14 of 15 outbreaks and one was caused by Sapovirus. The rates of vomiting and nausea were as high as that of diarrhea in Norovirus outbreaks. The rate of vomiting in Sapovirus was inclined to be lower than that due to Norovirus. The modes of transmission were identified as person-to-person contact in 3 cases, consumption of foods contaminated by food handlers in 4 cases and oysters in 3 cases, based on molecular investigations. The predominant probe type in Norovirus was G2F in genogroup II, followed by G2E and G1A, according to the classification of Fukuda et al. The Sapovirus was London type. Seasonal differences in the probe types of Norovirus were found. The involvement of multiple probe types was found in cases caused by the consumption of oysters.