[Norovirus infection in adults with sporadic gastroenteritis during 2007-2008 in Nanning Municipal].

Objective: To investigate the epidemiological characteristic and genotype distribution of norovirus infection among adult patients with sporadic gastroenteritis in Nanning Municipal.

Methods: The epidemiological data of adult diarrhea patients in outpatient clinics of a hospital in Nanning City between January 2007 and December 2008 were analyzed. A total of 696 fecal specimens were collected from the patients and were screened for the presence of norovirus RNA by real-time reverse transcription-polymerase chain reaction. Some positive specimens were selected randomly and subjected for sequencing and phylogenetic analysis to identify genotypes.

Results: The sporadic norovirus infection in adults occurred preferentially during the cold season, and there was no statistical difference in the detection rate between age groups. 183 (26.30%) of 696 specimens were positive for norovirus RNA. Among them, 180 (98.36%) belonged to genogroup II (G II) and the other 3 (1.64%) belonged to genogroup I (G I). The sequence analysis showed that all 10 G II strains selected randomly belonged to genotype G II4, while 3 GI strains were classified into three different genotypes: G I2, G I4 and G I8.

Conclusion: The study showed that norovirus was an important etiologic agent of sporadic gastroenteritis among adults in Nanning City. Genotype G II4 was the predominant genotype, and genotype GI existed sporadically.