[Genetic variation in VP7 gene of rotavirus serotype G3 predominated in Changchun, China].

Group A rotavirus (RV) is the most important etiologic agent of severe gastroenteritis among children and the development of an effective vaccine becomes the top public health priority. Since survey of RV serotypes circulating in local community is important for introduction or development of RV vaccine, RV serotype G3 had proved as the predominant strain in Changchun from 2001 to 2005. Stool specimens collected from children with acute diarrhea were tested for group A rotavirus by enzyme-linked immunosorbent assay (ELISA) and RV isolates were typed by reverse transcription-polymerase chain reaction (RT-PCR) using serotype-specific primers. The complete VP7 gene segments of 31 rotavirus strains selected in Changchun from 1999 to 2005 were amplified with RT-PCR. Amplicons were cloned and sequenced. Comparative analysis of the VP7 sequences showed that there were no obvious differences among 31 RV strains. There was similar genetic variation among VP7 genes during the same RV season. The nucleotide sequence of VP7 gene of six G3 RV strains had one base deletion at nt1038 in 2003 RV season. The nucleotide mutations in regions A, B and C of VP7 gene took place at the same position or position near-by. Increase of nucleotide mutation in non- high variation region may benefit maintenance of serotype G3 as pre dominant strain after 2002. Increase of non continuous variation in non-high variation regions was notable.

[Surveillance finding on rotavirus in Changchun children's hospital during July 1998-June 2001].

OBJECTIVE: To establish baseline patterns of rotavirus diarrhea and to describe its epidemiologic features in Changchun city, prior to rotavirus vaccine immunization. METHODS: Hospital-based surveillance was conducted among children under 5 years old with acute diarrhea in Changchun Children's Hospital. Fecal samples were determined to identify rotavirus by PAGE and/or ELISA. G serotypes of rotavirus were identified by ELISA and/or nested RT-PCR. P genotyping were carried out by RT-PCR. All data were computerized and analysed by "Generic Manual on Rotavirus Surveillance" set by CDC in the USA. RESULTS: In total, 2 343 diarrhea cases were screened and 1 211 fecal samples were collected. Rotavirus was detected in 31.0% among outpatients and 52.9% in inpatients. During the peak of the season (November through March), 58.6% of diarrhea was caused by rotavirus among inpatients. 95.0% of rotavirus diarrhea cases occurred among children aged < 2 years. The predominant strain was serotype G1 (82.4%), followed by G2 (5.0%), G3 (3.3%), G4 (0.9%). P genotyping showed that P[8] and P[4] were the most common ones. Nine different P-G combinations were identified, four strains (P[8]G1, P[4]G2, P[8]G3, and P[8]G4) commonly seen worldwide accounted for 75.6% of the total. Taken together with uncommon strains, including the novel types P[4]G4 and P[8]G2, it highlights the extraordinary diversity of rotaviruses circulating in China. CONCLUSION: Rotavirus is the major cause of severe child diarrhea in Changchun. Developing a rotavirus vaccine for prevention of severe disease and reduction of treatment costs seemed to be necessary.