Molecular epidemiological characteristics of noroviruses among infectious diarrhea patients in Harbin from 2014 to 2016

Objective To understand the epidemiological characteristics of norovirus in Harbin. Methods Fecal specimens were collected from 938 suspected diarrhea patients in sentinel hospitals of Harbin and from cases in two epidemic outbreaks of norovirus from 2014 to 2016. Norovirus RNA was detected by real-time RT-PCR. The positive specimens in 2016 were analyzed by sequencing. Results The positive rate of norovirus in patients with diarrhea was 18.02% (169/938) and all were positive of GII group. Four genotypes of norovirus were detected in the surveillance of sporadic cases, including 34 strains of GⅡ.P12/GⅡ.3, 15 strains of GⅡ.Pe/GⅡ.4, 11 strains of GⅡ.P17/GⅡ.17 and 2 strains of GⅡ.P16/GⅡ.2. The GⅡ.P16/GⅡ.2 variant and GⅡ.P17/GⅡ.17 variant caused the two epidemic outbreaks of norovirus in the schools. Conclusions The major pathogen causing infectious diarrhea in Harbin was norovirus GII group. The predominant strains in 2016 were GⅡ.P12/GⅡ.3 variant and GⅡ.Pe/GⅡ.4 variant. Key words: Novovirus; genotype; predominant strains