title: Characterization of Coxsackievirus A6- and Enterovirus 71-Associated Hand Foot and Mouth Disease in Beijing, China, from 2013 to 2015.
abstract: BACKGROUND
  Etiology surveillance of Hand Foot and Mouth disease (HFMD) in Beijing showed that Coxsackievirus A6 (CVA6) became the major pathogen of HFMD in 2013 and 2015. In order to understand the epidemiological characteristics and clinical manifestations of CVA6-associated HFMD, a comparison study among CVA6-, EV71- (Enterovirus 71), and CVA16- (Coxsackievirus A16) associated HFMD was performed.
  
  
  METHODS
  Epidemiological characteristics and clinical manifestations among CVA6-, EV71- and CVA16-associated mild or severe cases were compared from 2013 to 2015. VP1 gene of CVA6 and EV71 from mild cases, severe cases were sequenced, aligned, and compared with strains from 2009 to 2015 in Beijing and strains available in GenBank. Phylogenetic tree was constructed by neighbor-joining method.
  
  
  RESULTS
  CVA6 became the predominant causative agent of HFMD and accounted for 35.4 and 36.9% of total positive cases in 2013 and 2015, respectively. From 2013 to 2015, a total of 305 severe cases and 7 fatal cases were reported. CVA6 and EV71 were responsible for 57.5% of the severe cases. Five out six samples from fatal cases were identified as EV71. High fever, onychomadesis, and decrustation were the typical symptoms of CVA6-associated mild HFMD. CVA6-associated severe cases were characterized by high fever with shorter duration and twitch compared with EV71-associated severe cases which were characterized by poor mental condition, abnormal pupil, and vomiting. Poor mental condition, lung wet rales, abnormal pupil, and tachycardia were the most common clinical features of fatal cases. The percentage of lymphocyte in CVA6-associated cases was significantly lower than that of EV71. High percentage of lymphocyte and low percentage of neutrophils were the typical characteristics of fatal cases. VP1 sequences between CVA6- or EV71-associated mild and severe cases were highly homologous.
  
  
  CONCLUSIONS
  CVA6 became one of the major pathogens of HFMD in 2013 and 2015 in Beijing. Epidemiological characteristics, clinical manifestations of CVA6-, EV71- and CVA16-associated cases in this study enriched the definition of HFMD caused by different pathogens and shed light to accurate diagnosis, appropriate treatment and effective prevention of HFMD.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Capital Medical UniversityBeijing, China; Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease ControlBeijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Du
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Capital Medical University Beijing, China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Da
authors.initials: D
authors.lastname: Huo
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Capital Medical University Beijing, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Peng
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Capital Medical University Beijing, China.
authors.forename: Fen
authors.initials: F
authors.lastname: Liu
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Changying
authors.initials: C
authors.lastname: Lin
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Liang
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Jia
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chen
authors.affiliation: Beijing Center for Disease Prevention and Control, Institute for Infectious Disease and Endemic Disease Control Beijing, China.
authors.forename: Quanyi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Capital Medical University Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: He
keywords: Coxsackievirus A6; clinical features; enterovirus 71; epidemic; hand foot and mouth disease