Objective To analyze the genetic characteristics of norovirus detected in an acute gastroenteritis epidemic in an university in Gansu province in September 2–10, 2020, and provide evidence for the prevention and control of viral diarrhea caused by norovirus.
Methods A total of 232 stool samples were collected from the acute gastroenteritis cases with symptoms of vomiting and diarrhea in this epidemic. Real-time fluorescent PCR was used for preliminary screening and genome identification, and then reverse transcription polymerase chain reaction (RT-PCR) was used for positives sample amplification, and sequence determination of part of the polymerase region and capsid region was performed for the products with CT value less than 37, and software MEGA-X was used to construct a phylogenetic tree for genetic evolution analysis using the neighboring method.
Results The rate of diarrhea was 92.55%, the rate of abdominal pain was 88.94%, the rate of vomiting was 87.66%, and the rate of nausea was 78.09% in this acute gastroenteritis epidemic. The epidemic in the university was caused by co-infection of norovirus GⅠ and GⅡ. The detection rate of norovirus in 232 stool samples was 77.59% (180/232), and the detection rate of GⅠ was 16.38% (38/232), the detection rate of GⅡ was 44.83% (104/232) and the co-infection rate of GⅠ and GⅡ was 16.38% (38/232). As of 18:00 on September 10, 2020, a total of 470 students had been diagnosed with acute gastroenteritis, most were mild cases, among them 33 were admitted in hospital for observation and treatment. Based on sequencing, the genotypes of norovirus causing the epidemic were GⅠ.3［P10］, GⅠ.3［P13］, GⅠ.5［P4］, GⅡ.10［16］, GⅡ.17［P17］, GⅡ.22［PNA5］and GⅨ.1［GⅡ.P15］.
Conclusion There were 7 genotypes of norovirus detected in the acute gastroenteritis epidemic in this university, the first three were GⅡ.22［PNA5］, GⅠ.3［P13］, GⅨ.1［GⅡ.P15］. It is necessary to further strengthen the surveillance level and genotype analysis of norovirus in Gansu.
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