Epidemiological and etiological characteristics of norovirus infection in children under 5 years old in Hubei, 2018–2019

  Objective  To understand the epidemiological and molecular characteristics of norovirus associated with acute diarrhea in infants and young children in Hubei province from 2018 to 2019.

  Methods  A total of 922 stool samples from children aged ≤5 years with diarrhea were collected from viral diarrhea surveillance sentinel hospitals in Hubei Province from 2018 to 2019. The nucleic acids of norovirus GⅠ and GⅡ were detected by reverse transcription polymerase chain reactions. RT-PCR was used to amplify RNA polymerase and capsid region of the strain from norovirus positive samples and the PCR products were sequenced and genotyped.

  Results  Among the 922 stool samples collected, 122 were norovirus positive (13.23%), in which 119 were norovirus GⅡ positive (97.54%) and 3 were norovirus GⅠ positive (2.46%). The difference in the infection rate between boys and girls was significant ( χ²=8.805, P=0.003). Children aged ≤5 years, especially the infants aged6 - 12 months, were the population with high incidence. Norovirus infection mainly occurred in winter and spring, there were two incidence peaks, and the higher one occurred during October-December. Norovirus GⅡ was predominant and recombination genotypes were mainly GⅡ.4 Sydney ［P31］(27.71%), GⅡ.2［P16］(26.51%), GⅡ.3［P12］(26.51%) and GⅡ.4 Sydney ［P16］(16.87%).

  Conclusion  Multi genotypes and different recombination subtypes of norovirus were detected in children aged≤5 years with diarrhea in Hubei from 2018 to 2019. It is necessary to strengthen the surveillance for norovirus genotype and protect key population for the prevention and control of norovirus infection.