Epidemiological and genetic characteristics of norovirus in Hangzhou, China, in the postepidemic era

Danlei Chen; Qingyi Shao; Xuanwen Ru; Simiao Chen; Dongqing Cheng; Qing Ye

doi:10.1016/j.jcv.2024.105679

Epidemiological and genetic characteristics of norovirus in Hangzhou, China, in the postepidemic era

J Clin Virol. 2024 Apr 23:172:105679. doi: 10.1016/j.jcv.2024.105679. Online ahead of print.

Authors

Danlei Chen¹, Qingyi Shao¹, Xuanwen Ru², Simiao Chen², Dongqing Cheng³, Qing Ye⁴

Affiliations

¹ Department of Laboratory Medicine, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China; Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, China.
² Department of Laboratory Medicine, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China.
³ Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, China. Electronic address: chengdq@zcmu.edu.cn.
⁴ Department of Laboratory Medicine, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China. Electronic address: qingye@zju.edu.cn.

PMID: 38677156
DOI: 10.1016/j.jcv.2024.105679

Abstract

Objective: Norovirus (NoV) is an important human pathogen that can cause severe gastroenteritis in vulnerable populations. This study aimed to analyze the epidemiological and genetic characteristics of 2021-2023 NoV in Hangzhou, China.

Methods: This study enrolled patients aged 0-18 years who underwent NoV RNA detection in the hospital between January 2021 and October 2023 and analyzed the epidemiological characteristics of NoV. Polymerase chain reaction (PCR) was used to detect NoV RNA. Subtype classification and whole-genome sequencing were performed.

Results: There was a high prevalence of NoV infection in 2023, with NoV-positive samples accounting for 63.10 % of the total number of positive samples collected during the three-year period. The prevalence was abnormally high in summer, and the number of positive samples accounted for 48.20 % of the total positive samples for the whole year, which was much greater than the level in the same period in previous years (2023, 48.20% vs 2021, 13.66% vs 2022, 15.21 %). The GⅡ.4 subtype played a leading role, followed by increased mixed infection with GⅠ.5 and GⅡ.4. Whole-genome sequencing results suggested that GII.P16-GⅡ.4 had R297H and D372N key locus mutations. The evolutionary rate was 4.29 × 10^-3 for the RdRp gene and 4.84 × 10^-3 for the VP1 gene. The RdRp gene and VP1 gene of NoV GII.P16-GⅡ.4 have undergone rapid population evolution during the COVID-19 epidemic.

Conclusion: In the summer of 2023, an abnormally high incidence of NoV appeared in Hangzhou, China. The major epidemic strain GII.P16-GⅡ.4 showed a certain range of gene mutations and a fast evolutionary rate.

Keywords: Epidemiology; Genotype; Norovirus; Whole-genome sequencing.