The Genetic Diversity of Norovirus from Children with Diarrhea in Gwangju Metropolitan City, Korea: 2008-2012

In order to study the characteristics of norovirus in Gwangju metropolitan city, We examined norovirus in 13,931 fecal specimens collected through five years (2008-2012) from children admitted with a chief complain of acute diarrhea. Among a total of norovirus (NoV) was most frequently detected (3,025 cases, 21.7%). Concerning the frequency of virus detected by month, NoV tended to break out frequently from October to March in the following year. NoV was detected most highly in 0~3 year infants. Through examinations on NoV genotypes, among 3,025 cases that turned out to be positive, the genotypes of 2,652 cases were determined with various results including 13 types of GI and 17 types of GII. The results of analysis on GI genotypes were as follows: GI-4 (21.9%), GI-2 (15.2%), and GI-6 (10.5%). GII genotypes were as follows: GII-4 (63.9%), GII-3 (18.9%), GII-8 (4.2%), GII-2 (3.9%), GII-6 (3.3%), and GII-1 (1.9%). Eight types of variants for GII-4 genotype (427 cases) were identified. The majority of the GII-4 variants was GII-4_Farmington (181 cases, 42.4%), which peaked in 2012, while GII-4_2008b (173 cases, 40.5%) showed a high prevalence in 2011. Concerning the circulation of variants, as many as eight types of GII-4 variants were identified in 2012, showing more varieties than in other years. Therefore, this study can be used as fundamental data for the development of vaccine candidate for the prevention of viral diarrheal diseases with high-incidence.

An outbreak of inapparent non-O157 enterohemorrhagic escherichia coli infection / 대한내과학회지

BACKGROUND: No outbreak of Enterohemorrhagic Escherichia coli (EHEC) infection has occurred as a group in Korea. On July 2004, an outbreak of EHEC infection occurred in an elementary school in Gwangju metropolitan city. Epidemic investigation was undertaken to track the source of infection and the mode of transmission of EHEC. METHODS: All students and staffs of the elementary school were interviewed and completed questionnaires. We surveyed their clinical symptoms and the foods that they ate. Microbiologic examinations were also carried out on the above school-related persons and many environmental specimens. We also investigated the facilities of the school, some suppliers of food materials, and other associated institutions. All the EHEC-positive persons were isolated in 5 hospitals and tested everyday for verotoxin until they turned out to be negative twice in succession, and their family were also interviewed and tested for EHEC. Pulsed-field gel electrophoresis (PFGE) was performed to find out the genetic relationship between isolates. RESULTS: Of the 1,643 school-related persons, 77 persons (4.7%) were positive for EHEC. Most of them were asymptomatic. All the isolated strains were non-O157 EHEC. Serotype O91 was the most frequent serotype (68 isolates), and the isolates revealing O91 serotypes showed identical PFGE patterns. The school meal was significantly associated with this outbreak (relative risk=13.29, p=0.00). CONCLUSIONS: This is the first EHEC outbreak occurred as a group in Korea, All the isolated strains were non-O157 serotypes and the mode of transmission was most likely by school meal.