The Epidemiological Characteristics And Predominant Pathogen Analysis Of HFMD In Liaoning Province From 2012 To 2016

Backgroud: Hand Foot and Mouth Disease(HFMD)is a global acute infectious disease of children,often caused by multiple enteroviruses.The majority of patients are mainly infants and young children under the age of five.In 2008,HFMD was included in the statutory management of Class C infectious diseases in China.In recent years,the incidence and epidemic trend of HFMD in China has shown seasonal and periodic characteristics,with summer and autumn as the period of high incidence of epidemics.Enterovirus(EV)often causes many types of virus in HFMD,and it is commonly found in EV71 and CVA16 at home and abroad.In recent years,non-EV71non-CVA16 types(the other enteroviruses)have gradually become the dominant pathogenic type causing HFMD outbreaks.Among them,common HFMD cases caused by other enteroviruses,such as Coxasckievirus A10(CVA10)and Coxasckievirus A6(CVA6),have also been increasing year by year,and are attracting more and more attention.This poses new challenges to the prevention and control of HFMD.Objective: By collating and analyzing the HFMD case information from 2012 to2016 in Liaoning Province,and constructing the SARIMA model,comparing the gene mutation patterns of the VP1 region of the dominant pathogens in each year.Proven the epidemiological characteristics of HFMD epidemic in this province and forecast the future trend of the epidemic,to determine the pedigree composition of the dominant pathogens in each year and the variation and development of the strain type.Provide theoretical support and reference assistance for future HFMD prevention and control and promotion supervision in Liaoning Province.Methods: 1.Descriptive analysis was used to analyze the epidemiological characteristics of case information in the HFMD report information management system in Liaoning province from 2012 to 2016.2.The number of HFMD monthly reports from January 2012 to December 2016 in Liaoning Province was collected,and SPSS22.0 software was used to construct the SARIMA model.Fit the incidence and predict the incidence of HFMD in Liaoning province from January 2017 to December2018,and evaluate its prediction effect.3.According to the standard method of isolation and identification of enterovirus,RT-PCR rapid detection of HFMD samples was performed.A representative sample of positive isolates was selected using a random sampling method.Reverse transcription was performed on the VP1 segment of the RNA using specific primers,and the positive product was subjected to nucleotide sequence determination.The nucleotide sequence and amino acid homology of VP1 gene were compared by MEGA 6.0 software to construct a phylogenetic tree.Results: 1.Between 2012 and 2016,Liaoning Province reported a total of159,910 cases of HFMD,with a male to female ratio of approximately 1.46:1.The incidence of the main population is 0 to 6 years old children,accounting for 92.64% of the total number of cases,infants and young children under the age of 3 accounted for nearly 70% of patients in this age group(69.59%).The proportion of children with scattered children was the highest(48.87%),followed by children in childcare institutions(44.09%).2.The HFMD epidemic in Liaoning Province has significant seasonal and seasonal fluctuations.The epidemic began to rise in mid-April and peaked in July-August.The peak incidence in 2012-2015 was July,and the peak incidence in 2016 was August.The trend of the epidemic in each year gradually declined after September.3.The model(7)(8)(7)(8)12SARIMA0,1,10,1,0 ? residual sequence is white noise with a predicted average relative error of 0.229.The forecast results from2017 to 2018 show that from June to September is the peak period of HFMD in Liaoning Province,consistent with previous epidemiological survey results,and theprediction results are better.4.Between 2012 and 2016,there were alternating changes in the dominant pathogenic types of Liaoning Province in each year.In 2012,2014,and 2016,the dominant type was dominated by CVA16,and in 2013 and 2015,CVA6 types of other enteroviruses were predominant.5.The HFMD pathogen sequence in Liaoning Province was determined and compared.The CVA16 isolates were B1 a and B1 b subtypes with nucleotide homology of 87.7% to 100% and amino acid homology of 96.9% to 100%.The CVA6 isolates were G and H lines with nucleotide homology of 97.0% to 100%,amino acid homology of 96.9% to 100%,and close genetic relationship.The result of homologous analysis is consistent with relevant domestic reports.Conclusions: 1.The incidence of HFMD in Liaoning province from 2012 to 2016 was mainly concentrated in children aged 0 to 6 years old,with infants under 3 years old as the main population.2.The HFMD epidemic in Liaoning Province was at the peak of onset from July to August,with obvious seasonal and periodic fluctuation characteristics,consistent with the results of previous studies.3.The model(7)(8)(7)(8)12SARIMA0,1,10,1,0 ? is the best prediction model,the average relative error of the prediction is smaller.The prediction of the short-term fluctuation trend of the HFMD epidemic situation in Liaoning Province is more satisfactory.4.In 2012,2014,and2016,the dominant pathogen of HFMD in Liaoning Province was CVA16.In 2013 and2015,the dominant HFMD pathogen in Liaoning Province was CVA6.5.The HFMD pathogen sequence analysis and comparison in Liaoning Province showed that the CVA16 virus epidemic strain belongs to the B1 a and B1 b subtypes,and the CVA6 virus epidemic strain belongs to the G and H lineages,which is consistent with the relevant conclusions in China.