title: Epidemic characteristics of hand, foot, and mouth disease in Shanghai from 2009 to 2010: Enterovirus 71 subgenotype C4 as the primary causative agent and a high incidence of mixed infections with coxsackievirus A16.
abstract: BACKGROUND
  Enterovirus 71 (EV71) has been the main causative agent of hand, foot, and mouth disease (HFMD) outbreaks in recent years. A significant increase in the number of HFMD cases in China over the last 3 y has made the public prevention and therapy of this disease a critical issue.
  
  
  METHODS
  A total of 3208 HFMD patients in Shanghai during the period 2009 to 2010 were analyzed; 437 clinical specimens were collected for the determination of causative pathogens. Eight of the isolated EV71 strains were sequenced and phylogenetically analyzed.
  
  
  RESULTS
  The widespread outbreak of HFMD in Shanghai was caused predominantly by EV71 (86.5%), and in part by coxsackievirus A16 (CA16) (6.9%). The high incidence of mixed infections with EV71 and CA16 (17.6% of the total CA16-infected cases) has never before been observed in China. Most HFMD patients (76.9%) were aged 1-4 y. Boys showed a higher HFMD prevalence rate (65.3%) than girls (34.7%). Phylogenetic analysis on the basis of the VP1 gene and the complete genome sequences revealed that the EV71 strains that circulated in Shanghai belonged to the C4 subgenotype.
  
  
  CONCLUSIONS
  EV71 subgenotype C4 was the major causative agent of the HFMD outbreak in Shanghai. A high incidence of mixed infections with EV71 and CA16 was also observed.
authors.affiliation: Laboratory of Medical Microbiology, Department of Medical Microbiology and Parasitology, Shanghai Medical College of Fudan University, Shanghai, China.
authors.forename: Xiu-Feng
authors.initials: XF
authors.lastname: Yan
authors.forename: Shuang
authors.initials: S
authors.lastname: Gao
authors.forename: Ju-Feng
authors.initials: JF
authors.lastname: Xia
authors.forename: Rong
authors.initials: R
authors.lastname: Ye
authors.forename: Hui
authors.initials: H
authors.lastname: Yu
authors.forename: Jian-Er
authors.initials: JE
authors.lastname: Long
mesh_terms: D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D060085:Coinfection / Q000453:epidemiology* / Q000821:virology*; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D004770:Enterovirus / Q000235:genetics / Q000302:isolation & purification; D029821:Enterovirus A, Human / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D006232:Hand, Foot and Mouth Disease / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D010802:Phylogeny