The Etiological Features Of Hand Food And Mouth Disease And Molecular Typing Of EV71 And CVA16 In Changchun City In 2015

Background and Objective:Hand,foot and mouth disease(HFMD)is caused by human enterovirus,morbidity and mortality in recent years is the highest in C class infectious disease in China.Minority patients may have severe complications such as aseptic meningitis,neurogenic pulmonary edema and myocarditis symptoms,and individual severe patients even death.Currently reported human enterovirus causes HFMD has more than 20,EV71 and CVA16 is the main pathogens cause of HFMD.With the generation sequencing technology and data resource sharing,based on the nucleotide of molecular biology research for the evolution of the virus provides a convenient method.Therefore,to illustrate the main pathogens of HFMD in Changchun city in 2015,we analyzed the etiological features of HFMD in Changchun city in 2015.Analyzed the molecular typing and hereditary evolution of EV71 and CVA16 to further expound their hereditary evolution rule and characteristics.This study will provide the scientific basis to prevent and control HFMD in Changchun and vaccine research.Material and Method: We collected 36 specimens about suspected cases of HFMD in Changchun city in 2015.RD cell was used for virus isolation and culturing.Typical cytopathic effect(CPE)specimens were extracted RNA of virus and identified by using enterovirus universal primer,EV71-specific primer and CVA16-specific primer.Using PCR to amplify VP1 coding region and the PCR products were sent to Shanghai Sangonsequencing.We analyzed the homology in nucleotide and amino acid of EV71-VP1 and CVA16-VP1 and constructed thephylogenetic tree by using Bioedit and MEGA6.0 software.Results and Conclusion:Peak of HFMD mainly concentrated in four to six month,accounting for 44.4% of the cases collected throughout the year,with 2015 national,HFMD incidence peak is consistent.There was no significant difference on gender composition.Onset age have focused on children aged 2 to 4,accounting for 75% of the total number of incidence,the largest number occurred is 3 years old group,accounting for 33.3%.This study we isolated 17 enteroviruses strains and the positive rate was 47.2%.There were five EV71(ratio of 29.4%),six CVA16(ratio of 35.3%)and six other kind of enteroviruses(ratio of 35.3%).The result showed that in addition to EV71 and CVA16,other kind of enteroviruses also occupied very important position in HFMD pathogen spectrum in Changchun city in 2015.It was found that the homology between the five EV71 strains were higher in nucleotide and amino acid,the homology was 96.2%-97.7% and 99.2%-99.5%.And the VP1 sequences of five EV71 strains were no obvious difference.The phylogenetic tree revealed that five EV71 strains were all belong to C4 a subtype,respectively,which is consistent with the other region of epidemic strains.It was found that the homology between the six CVA16 strains were higher in nucleotide and amino acid,the homology was 97.4%-99.9% and 99.3%-99.9%.And the VP1 sequences of six CVA16 strains were no obvious difference.The phylogenetic tree revealed thatsix CVA16 strains were all belong to B2 b subtype,respectively,which is consistent with the other region of epidemic strains.Because of no emergence of new subtype,it provides a good opportunity for development of vaccines.