Molecular Epidemiological Study On Viral Diarrhea In Children Under 5 Years Old In Lanzhou,2017

PART 1:MOLECULAR EPIDEMIOLOGICAL STUDY ON VIRAL DIARRHEA IN CHILDREN UNDER 5 YEARS OLD IN LANZHOU,2017Objective This study analyzed the prevalence of four major diarrhea viruses in children under 5 years of age in Lanzhou in 2017,and provided scientific data for the prevention and treatment of viral diarrhea.Methods Collected all of 219 fecal samples from children under 5 years of age with acute diarrhea who were admitted to the Department of Pediatrics of Lanzhou University in 2017.Group A rotavirus antigens were detected by double-sided sandwich enzyme-linked immunosorbent assay(ELISA).G and P typing were performed by reverse transcription-polymerase chain reaction(RT-PCR),calicivirus and astrovirus were detected by RT-PCR,adenovirus was detected by PCR,and positive samples verified by electrophoresis were subjected to gene sequencing type.Results Among the 219 samples,the total detection rate of virus was 80.37%,among which the first group was group A rotavirus,accounting for 51.60%,followed by calicivirus(20.09%),adenovirus(4.11%)and astrovirus(4.57%).The results of typing showed that G9(90.27%)was the main G genotype of group A rotavirus,P[8](91.15%)was the main P genotype,followed by P[4](7.96%).The mainly component is G9P[8] in combination(88.50%).The results of the calicicirus are all Norovirus,no saporovirus was detected.GII-4(52.27%)of Norovirus need to be predominant in the fires place,and GII-3(36.36%)in the next place.Finally,only 1 case was GI-3.The type 41(55.56%)of the Group F was the mainly genotype of adenovirus and all of the astroviruses were Ast V-1.The most seasonal distribution is characterized by Group A rotavirus in the fourth quarter,high-risk groups are concentrated in the 0-18 months old.Conclusion The pathogens of viral diarrhea children under 5 years old in Lanzhou are diverse.Group A rotavirus is the most important pathogen,followed by norovirus,the main epidemic strain are G9P[8] and GII-4,The dominant genotypes are the same as those prevalent in recent years.PART2:ANALYSIS OF A GROUP HUMAN ROTAVIRUS G9P[8] AND G2P[4] VP7,VP4 GENESObjective In 2017,the epidemic genotype of group A human rotavirus in Lanzhou was G9P[8],followed by G2P[4].At the same time,in order to analysis the molecular epidemiological characteristics and evolution of G9P[8] and G2P[4] in Lanzhou,We provided basic data for defense rotavirus infection and development of rotavirus vaccine in our country.Methods For 10 cases of G2P[4] fecal samples from the Department of Pediatrics of Lanzhou University First Hospital from July 2016 to December 2017 were selected.And for 11 cases of G9P[8] fecal samples from the Department of Pediatrics of Lanzhou University First Hospital during the period from January to December 2017.Through specimen processing,nucleic acid extraction,RT-PCR amplification,T-A cloning and sequence determination of VP4 and VP7 gene fragments,sequence alignment and construction of phylogenetic tree were performed using MEGA7.0 software and reference strain sequences from Gen Bank.Results In the G9 VP7 genes of Lanzhou in 2017,It has 8 cases were successfully sequenced,which belong to the sixth branch of Group A human Rotavirus,It’s closely related to other provinces in China and its surrounding countries in 2011-2017,which homology is 98 %-99 %.The 10 successfully sequenced strains of the G2 P strain in Lanzhou from 2016 to 2017 were closely related to the evolution of G2 strains in different years in other countries.In 2017 of Lanzhou,Type strains of P[8] in other regions and neighboring countries of China from 2013 to 2016,At the same time,The reference plant relationship is relatively closed.In 2016-2017,11 cases of Lanzhou The type strains of P[4] are closely related to other regions and other countries in China,which was a homology of 96 %-99 %.Conclusion G9 is the dominant genotype of RVA in Lanzhou in 2017,which is consistent with the domestic trend in recent years.Through the systematic evolution analysis of the G9 type VP7 gene in Lanzhou of this time,the G9 of Lanzhou is closer to the other regions of China and neighboring countries.The G2 genotype has a closed relationship with other parts of China and neighboring countries,and there may be similar kinship in a long time distribution.P genotype is relatively stable,with P[8]and P[4] in China,the same situation in other parts of China and neighboring countries.