Analysis of infection status and recombination types of norovirus in patients with acute gastroenteritis in the Ningxia Hui Autonomous Region from 2016 to 2017

Abstract

Objective: To analyze the infection status and recombination of Norovirus in patients with acute gastroenteritis in Ningxia. Methods: The specimens of 10 sentinel hospitals in Ningxia were collected from 2016 to 2017. Real-time quantitative PCR was used for nucleic acid detection. GⅡ-positive samples were amplified by RT-PCR for the RdRp and Capsid regions, then sequenced and genotyped. Evolution analysis was performed using software such as MEGA-X, and recombination analysis was performed using Simplot 3.5.1 and RDP4. Results: The age of the 2 334 cases was 1.42 (0.68, 7.69) years old, 1 133 cases in 2016 and 1 201 cases in 2017, 1 343 and 991 cases for males and females respectively. The positive rate of Norovirus GⅠ genogroup was 0.86% (20/2 334), and GⅡ genogroup was 14.82% (346/2 334). A total of 78 recombinant strains were sequenced and 12 recombinant types were found. GⅡ.Pe/GⅡ.4Sydney_2012 and GⅡ.P12/GⅡ.3 were the main epidemic strains, accounting for 35.90% (28 strains) and 32.05% (25 strain) respectively, followed by GⅡ.P16/GⅡ.2 accounting for 12.82% (10 strains). Among them,GⅡ.P7/GⅡ.6 (2 strains), GⅡ.P12/GⅡ.3 (6 strains), GⅡ.P16/GⅡ.1 (2 strains), GⅡ.P16/GⅡ.2 (5 strains), GⅡ.Pe/GⅡ.4 (7 strains) were detected for the first time in Ningxia. Recombinant strains were all intergenotype recombination, and the recombination breakpionts were all located within ORF1. Conclusion: Norovirus infection in Ningxia area was mainly in GⅡ genogroup from 2016 to 2017, and most of them were recombinant strains. GⅡ.Pe/GⅡ.4Sydney_2012 and GⅡ.P12/GⅡ.3 were the main epidemic strains, followed by GⅡ.P16/GⅡ. 2.