Clinical Characteristics Of EV71 Hand-foot-mouth Disease In Suzhou Area And Its VP1 Genotyping

Objective:1.By investigating the epidemiology,clinical features and laboratory results of hand-foot-mouth disease hospitalized children with Enterovirus 71(EV71)in the Children’s Hospital of Suzhou University from 2015 to 2017,to explore the clinical characteristics and independent risk factors of developing to severe typen of EV71 hand,foot and mouth disease,to improve the ability of identifying early-onset children with severe EV71 hand,foot and mouth disease2.Carry out the sequence analysis of EV71VP1 region in Suzhou area from 2015 to 2017,and compare and analyze the homology with other domestic EV71 strains to understand the prevalence of EV71 strain in Suzhou area,and provide evidence for prevention and treatment of EV71 infection in this area.Method:1.The clinical data of 861 children with EV71-positive hand-foot-mouth disease admitted to the Children’s Hospital of Suzhou University from 2015 to 2017 were selected as the study subjects.All cases were classified as severe group and general group,according to the hand,foot and mouth disease diagnosis and treatment guidelines(2010 edition).There were 319 patients in the severe group and 542 patients in the general group.Their epidemiological,clinical features and laboratory results were retrospectively analyzed.Multivariate unconditional logistic regression was used to analyze the independent risk factors of severe EV71 hand,foot and mouth disease.2.Collected 9 cases of EV71-positive throat swab specimens from Suzhou Center for Disease Control and Prevention from 2015 to 2017,and reverse transcription-polymerization(RT-PCR)technique was used to amplify full-length of VP1 region,and use the corresponding bioinformatics software for nucleotide and amino acid sequence alignment and establishing phylogenetic tree analysis.Result:1.The attack time of EV71 type hand-foot-mouth disease in the general group and the severe group was basically same.The high-risk period of the disease was from May to July in the year old of 1 to 3.Their are 538 males and 323 females,the ratio of male to female is 1.67:1.The clinical manifestations of the two groups were statistically analyzed.The fever time,heat peak,mental retardation,jitter,headache,vomiting,neck resistance,and Pap smear positive in the severe group were significantly higher than those in the normal group(P<0.01).In addition,respiratory and gastrointestinal complications have no significant differences in two groups(P>0.05).2.Statistical analysis was performed on the laboratory tests of the two groups.The results showed that there were statistical differences in peripheral blood central granulocyte ratio,creatine kinase isoenzyme(Creatinekinase-MB,CKMB),CD3+CD4+、CD3-CD19+and CD4+/CD8+.(P<0.05).Peripheral blood leukocyte count,platelet count,blood glucose,C reactive protein(CRP),Alanine aminotransferase(ALT),troponin,CD3+,CD3+CD8+、CD3-CD(16+56)+and CD19+CD23+have no differences between two groups.(P>0.05).In addition,in the cerebrospinal fluid results of 319 cases of EV71 type hand-foot-mouth disease severe group,white blood cell count of 273 cases(85.6%),total protein content of 64 cases(20%),IgA of 170 cases(53.3%),IgG of 58 cases(18.2%)and IgM of 168 cases(57.2%)are increased.3.Multivariate unconditional logistic analysis showed that jitter,vomiting,neck resistance,positive Pap smear,and mental retardation were independent risk factors for severe EV71 hand-foot-mouth disease(OR=14.124,1.771,10.145,24.084,5.985,P<0.05).4.The similarity of the nucleotide and amino acid sequences of the VP1 gene of 9 strains of EV71 was 91.5%-99.3%and 91.9%-100%,respectively.Nine strains of EV71 isolates were in the same branch of the C4a subtype representative strain in the phylogenetic tree.9 strains of EV71 isolates and Fuyang strains and Suzhou C4 subtypes were on the phylogenetic tree,and the representative strain of C4 subtype in Suzhou area and the 8 isolates of EV71 were similar to the representative strain of Fuyang,and only one isolate of EV71 was detached from the phylogenetic tree.Conclusion:1.High incidence age of the EV71 type of hand,foot and mouth disease is 1-3 years old,which occurs in May to July.The children in the severe group have longer fever time,higher heat peak,and the white blood cell count are similar to the genaral group.2.Jitter,vomiting,neck resistance,positive Pap smear,and mental retardation are independent risk factors for severe EV71 hand,foot and mouth disease.In 2015-2017,9 strains of EV71 isolates and C4a subtypes in Suzhou located in the same branch and belonged to the C4a genotypes,at the same time,they occured multiple amino acid variations.Eight strains of 9 strains of EV71 were derived from Fuyang strain.