Surveillance of pathogens causing gastroenteritis and characterization of norovirus and sapovirus strains in Shenzhen, China, during 2011.

Viral gastroenteritis is one of the most common diseases in humans, and it is primarily caused by rotaviruses (RVs), astroviruses (AstVs), adenoviruses (AdVs), noroviruses (NoVs), and sapoviruses (SaVs). In this study, we determined the distribution of viral gastroenteritis and human calicivirus (HuCVs) in acute gastroenteritis patients in Shenzhen, China, during 2011. Real-time RT-PCR was used to detect norovirus (NoV), group A rotavirus (RV), adenovirus (AdV), and astrovirus (AstV). From a total of 983 fecal samples, NoV was detected in 210 (21.4 %); RoV in 173 (17.6 %); AstV in 10 (1.0 %); and AdV in 15 (1.5 %). Mixed infections involving two NoVs were found in 21 of the 387 pathogen-positive stool specimens. NoV and SaV genotypes were further tested using RT-PCRs and molecular typing and phylogenetic analysis were then performed based on the ORF1-ORF2 region for NoV and a conserved nucleotide sequence in the capsid gene for SaV. Of the 68 typed strains that were sequenced and genotyped, five were NoV G1 (7.5 %) and 63 were NoV GII (96.6 %). GII strains were clustered into five genotypes, including GII.4 (65.1 %; 36 GII.4 2006b and five GII.4 New Orleans), GII.3 (28.6 %), GII.2 (3.2 %), GII.6 (1.6 %), and GII.1 (1.6 %). While all fecal specimens were tested for SaVs, 15 (1.5 %) were positive, and of these, 12 isolates belonged to G1.2, and the remaining three SaV strains belonged to the SaV GII genogroup. Although various HuCVs were detected in acute gastroenteritis patients, NoV GII.4 2006b was more prevalent than the other HuCVs.