Prevalence of noroviruses in children hospitalized for acute gastroenteritis in Hohhot, China, 2012-2017

BACKGROUND: Noroviruses (NVs) are an important cause of acute gastroenteritis (AGE) worldwide. There are limited data on the prevalence and molecular characterization of NVs in children in Hohhot, China. METHODS: Between January 2012 and December 2017, 1863 stool samples were collected at Maternal and Child Health Hospital in Hohhot. All samples were screened for NVs by real-time reverse transcription polymerase chain reaction (real-time RT-PCR). RESULTS: NVs were detected in 24.15% of these inpatient cases, ranging from 12.78 to 32.92% in different years. NV was detected throughout the year, with a peak in winter. Based on sequence analysis of the partial VP1 gene, the 306 identified NV strains were divided into six genotypes: GII.3 (71.24%), GII.4 (23.53%), and GII.2, GII.5, GII.6, and GII.13 (total 5.23%). Based on further sequence analysis of the RNA-dependent RNA polymerase (RdRp), GII.P12/GII.3, GII.Pe/GII.4, and GII.P4/GII.4 were identified as predominant genotypes, accounting for 92.6% of genotyped strains. The median age of the children with NV infection was 8.0 (range 0–59) months. However, children infected with GII.3 were younger (median 7.0 months) than GII.4-positive patients (median 10.0 months). CONCLUSION: NV contributed greatly to AGE among hospitalized children in Hohhot in China. Continuous surveillance is important for understanding the local prevalence and characterization of NV.