2017—2020年天津市GII型诺如病毒感染的流行病学特征

Epidemiological characteristics of norovirus GII infection in Tianjin city,2017-2020

目的分析天津市住院急性胃肠炎患儿中诺如病毒(norovirus,NoV)感染的流行病学及临床特征,为临床诊疗提供理论依据。方法收集2017年8月至2020年7月天津市儿童医院住院急性胃肠炎患儿的粪便标本,采用实时荧光逆转录聚合酶链反应(reverse transcription-polymerase chain reaction,RT-PCR)检测NoV,采用普通RT-PCR方法对阳性样本衣壳蛋白VP1区进行扩增,产物送检测序后基于序列进行分型,并比较感染不同基因型NoV患儿的临床症状差异。结果NoV检出率为26.5%(1703/6432),761份阳性样本获得VP1区测序信息,共得到7种基因型,其中GII.4、GII.3、GII.2、GII.17、GII.1、GII.13和GII.6型分别占55.5%(422/761)、36.7%(279/761)、4.9%(37/761)、0.9%(7/761)、0.8%(6/761)、0.8%(6/761)和0.5%(4/761);GII.4型均为GII.4 Sydney 2012。感染GII.4和GII.其他型的患儿发病季节分布差异具有统计学意义(χ^(2)=103.53,P<0.001);感染GII.4型较其他型NoV的患儿更易出现腹泻、呕吐和脱水症状(χ^(2)=8.42,P=0.004;χ^(2)=20.39,P<0.001;χ^(2)=4.99,P=0.025)。结论2017—2020年天津市儿童NoV感染以GII.4和GII.3型为主,且基因型呈多样性,感染GII.4型患儿更易出现腹泻、呕吐和脱水症状。

Objective To investigate the molecular epidemiologic and clinical characteristics of norovirus(NoV)in hospitalized children with acute gastroenteritis(AGE)in Tianjin to provide theoretical basis for clinical diagnosis and treatment.Methods Fecal specimens were collected from children with AGE in Tianjin Children′s Hospital from August 2017 to July 2020.NoV was detected by real-time fluorescence reverse transcription-polymerase chain reaction(RT-PCR).Partial sequence of the capsid protein VP1 of positive samples was amplified by conventional RT-PCR.The products were sent for sequencing and genotyping based on the sequence.As the same time,the clinical symptoms were compared among children infected with different NoV genotypes.Results Among the 6432 specimens,1703(26.5%)were positive for NoV.Sequence analysis showed that 761 identified NoV strains could be divided into 7 genotypes.Genotypes GII.4,GII.3,GII.2,GII.17,GII.1,GII.13 and GII.6 accounted for 55.5%(422/761),36.7%(279/761),4.9%(37/761),0.9%(7/761),0.8%(6/761),0.8%(6/761)and 0.5%(4/761),respectively.All of the GII.4 belonged to GII.4 Sydney 2012.There was also a significant difference in the seasonal distribution of children infected with GII.4 and other genotypes(χ^(2)=103.53,P<0.001).Children infected with GII.4 NoV were more likely to have diarrhea,vomiting and dehydration(χ^(2)=8.42,P=0.004;χ^(2)=20.39,P<0.001;χ^(2)=4.99,P=0.025).Conclusions GII.4 and GII.3 were mainly genotypes of NoV infection in Tianjin from 2017 to 2020 and genotypes were diverse.In addition,children with GII.4 NoV were more likely to suffer from diarrhea,vomiting and dehydration.