Epidemiologic Characteristics Of Hand,Foot And Mouth Disease And Gentic Characteristics Of CV-A6 In Ningxia,China,2017-2018

BackgroundHand,foot,and mouth disease(HFMD)is a common acute disease in children.It is caused by Enterovirus(EV).The morbidity and mortality of HFMD are always in the top of the list of reported infections diseases in China.According to previous studies,the most common pathogens causing HFMD in China were Enterovirus A71(EV-A71)and Coxsackievirus A16(CV-A16).However,report of HFMD caused by Coxsackievirus A6(CV-A6)have been increasing in recent years,and become one of the main pathogenic pathogens.The influence of HFMD on public health in China cannot be ignored.Objective1.We wished to understand the epidemiologic characteristics of HFMD in Ningxia,and to analysis the epidemic characteristics and pathogenic spectrum.2.Analysis the molecular epidemiology of CV-A6 strains isolated from Ningxia.Analysis the VP1 region sequence and the full-length genome sequence to understand the genetic of Ningxia CV-A6 strains.Methods1.The epidemic characteristics of HFMD in Ningxia were described by analyzing the monitoring data of HFMD from 2017 to 2018.2.Analysis the detection and isolation results of virus in laboratory to describe the pathogen spectrum.Results1.From 2017 to 2018,a total of 14698 cases of HFMD were reported in Ningxia autonomous region,with an incidence of 111.62/100000 in 2017 and 105.09/100000 in 2018.2.The incidence of HFMD in Ningxia has obvious seasonal characteristics,mainly in the summer and autumn season,there are two incidence peaks.The first and the main incidence peaks is May to August,and the second incidence peaks is October to November.3.HFMD has been found in all five regions in Ningxia,but the number of patients are varies.The number of cases in 2017 and 2018 from high to low is: Yinchuan,Wuzhong,Zhongwei,Shizuishan,Guyuan.Yinchuan has the largest number of patients,accounting for 47.03% and 60.08% of the total patients in 2017 and 2018.4.In Ningxia,HFMD patients are mainly concentrated in children under 6 years old,and most of them are 1 to 4 years old.The incidence decreases with age.The number of male patients was significantly higher than female patients,and the ratio was 1.45:1.5.From 2017 to 2018,a total of 2958 cases were diagnosed in the laboratory.In 2017,the pathogen spectrum was composed of EV-A71(56.22%),CV-A16(6.43%),and other EVs(37.35%).In 2018,the pathogen spectrum was composed of EV-A71(1.58%),CV-A16(27.70%),and other EVs(70.70%).The dominant pathogens in each month and age group were consistent with the dominant pathogens in each year.6.A total of 133 EV strains were isolated,among which CV-A6 accounted for the largest proportion,accounting for 18.80% of the isolated in 2017 and 15.26% in 2018.7.The homology between the Ningxia CV-A6 strain and the CV-A6 prototype strain in 2018 is lower than 2017.It indicating that the CV-A6 in Ningxia is still evolving.Through genetic evolution tree analysis,all the Ningxia strains are D3 a gene subtype.8.Simplot was used to analyze the similarity and recombination,and it was found that there might be three recombination patterns in the sequence of CV-A6 in Ningxia,and EV-A114 might be the main donor,but further study is needed.Conclusion1.In Ningxia,HFMD was mostly found in children under 6 years old,and the 1-year group had the largest number of cases and the highest incidence.The incidence of HFMD in Ningxia has obvious seasonal characteristics,mainly in the summer and autumn season,there are two incidence peaks.The first and the main incidence peaks is May to August,and the second incidence peaks is October to November.Yinchuan have the largest number of patients.2.EV-A71 and CV-A16 are still the main pathogens of HFMD in Ningxia,they alternate as the dominant pathogen.