Molecular Epidemiologic Investigation of Norovirus Infections in Incheon City, Korea, from 2005 to 2007

Noroviruses (NoVs) cause major epidemic gastroenteritis in humans. To obtain the molecular epidemiological information on gastroenteritis sporadic cases in Incheon city, Korea, we analyzed the nucleotide sequences of NoV strains detected during 2005~2007. We performed one step RT-PCR amplifying the open reading frame (ORF) 2 (capsid region) followed by semi-nested PCR from the stool samples from acute gastroenteritis patients from 2005 to 2007. Amplicons of the capsid region of norovirus strains were sequenced and analyzed using MegAlign in DNAstar software. Faecal samples were collected from 6,618 acute gastroenteritis patients during the study period. The incidence of NoV infection was about 10.7% (n=708) among patients with acute gastroenteritis and genotypes of the 320 positive samples were determined by sequence analysis. Sequence comparison of NoV strains revealed that 16 genotypes of GII NoV strains were circulated in Incheon city, from 2005 to 2007. Among norovirus strains, the most prevalent genotype GII/4 was most common 69.7% (223 strains), followed by GII/3 17.2% (55 strains), GII/12 4.4% (14 strains), GII/1 2.2% (7 strains), GII/5 1.6% (5 strains), GII/15 1.3% (4 strains) and 0.6% (2 strains) each of GII/9 and GII/16. The GII-3 strains were most frequently detected in Incheon, 2005. From the phylogenetic analysis of NoV strains, we detected 16 genotypes of GII NoV strains during 2005~2007 in Incheon. Our results suggest that various genotypes of human NoV strains in sporadic case of AGE were circulated in Incheon, Korea.

The Prevalence and Genotypic Distribution of Group A Rotavirus Detected from Patients with Acute Gastroenteritis Patients in Incheon

This study has focused on genetical patterns of rotavirus positives on diarrhea patients in Incheon. Fecal specimens collected from January 2002 to December 2004 from patients with diarrhea in seven localities in Incheon were screened for group A rotavirus by RT-PCR. To survey the prevalence of group A rotavirus infection and distribution of P (VP4) and G (VP7) genotypes of rotaviruses in Incheon, we performed the nested RT-PCR using rotavirus ELISA positive samples. Among a total of 4,865 samples investigated, 1,100 samples (22.6%) were positive. The predominant genotypes of 293 RT-PCR positive samples were confirmed as G4P[6] (101 samples, 34.5%) followed by G2P[4] (73 samples, 24.9%), G1P[8] (38 samples, 13.0%), G3P[8] (28 samples, 9.6%), G3P[10] (14 samples, 4.8%), G4P[8] (6 samples, 2.0%) and G9P[8] (6 samples, 2.0%). Mixed types and untypable types were 3.8% and 5.1%, respectively. The most prevalent types in 2002, 2003 and 2004 were G4P[6] (71 samples, 40.3%), G4P[6] (22 samples, 40.7%) and G2P[4] (15 samples, 22.2%) respectively. This is the first nationwide genoepidemiological study for determining the prevailing of genotypes of rotaviruses in Incheon. The genetic analysis for investigating sequence variations among group A rotavirus strains in this study would provide the useful information to establish the preventing strategy of human rotaviruses and of developing vaccines which will be used in Korea.

Epidemiological Analysis of Influenza by Laboratory Surveillance in Incheon, 2003/2004~2004/2005 / 대한임상미생물학회지

BACKGROUND: Influenza is a highly contagious respiratory disease. Influenza virus, which causes epidemics every winter season, has the high possibility of appearing with new virus types every year due to antigen variation. Therefore, we intended to analyze the data on the epidemiology of influenza that had been acquired by laboratory surveillance in Incheon during the 2003/2004 and 2004/ 2005 seasons and to apply the knowledge to the control and prevention of influenza in Korea. METHODS: Specimens were inoculated into Madin-Darby canine kidney (MDCK) cells and, when cytopathic effect (CPE) was seen, culture supernatants were tested by mutiplex RT-PCR for typing and subtyping of influenza viruses. RESULTS: The first virus of the season was isolated at week 47 (3rd week on November) in 2003 during 2003/2004 and at week 43 (4th week on October) in 2004 during 2004/2005, which was about 4 weeks earlier than in the 2003/2004 season. From 532 specimens cultured for influenza virus during the 2003/2004 season. 330 (62.0%) viruses were isolated: 161 (48.8%) A/H3N2, 1 (0.3%) A/H1N1, and 168 (50.9%) B. During 2004/2005 season, 457 specimens were tested and 278 (60.8 %) were positive for influenza virus: 232 (83.5%) A/H3N2, 5 (1.8%) A/H1N1, and 38 (13.7%) B. The incidence of influenza was the highest in the school-age children and young adults of 7 to 19 years age group in both seasons. CONCLUSION: Influenza virus was isolated at a high rate (more than 60%) by the laboratory influenza surveillance system in Incheon during the 2003/2004 and 2004/2005 seasons: the predominant strain was influenza A/H3N2 subtype.