title: Hand, foot, and mouth disease in China: patterns of spread and transmissibility.
abstract: BACKGROUND
  There were large outbreaks of hand, foot, and mouth disease in both 2008 and 2009 in China.
  
  
  METHODS
  Using the national surveillance data since 2 May 2008, we summarized the epidemiologic characteristics of the recent outbreaks. Using a susceptible-infectious-recovered transmission model, we evaluated the transmissibility of the disease and potential risk factors.
  
  
  RESULTS
  Children ages 1.0 to 2.9 years were the most susceptible to hand, foot, and mouth disease (odds ratios [OR] >2.3 as compared with other age-groups). Infant cases had the highest incidences of severe disease (ORs >1.4) and death (ORs >2.4), as well as the longest delay from symptom onset to diagnosis (2.3 days). Boys were more susceptible than girls (OR = 1.56 [95% confidence interval = 1.56-1.57]). A 1-day delay in diagnosis was associated with increases in the odds of severe disease by 40% (39%-42%) and in the odds of death by 54% (44%-65%). Compared with Coxsackie A16, enterovirus 71 is more strongly associated with severe disease (OR = 16 [13-18]) and death (OR = 40 [13-127]). The estimated local effective reproductive numbers among prefectures ranged from 1.4 to 1.6 (median = 1.4) in spring and stayed below 1.2 in other seasons. A higher risk of transmission was associated with temperatures in the range of 70° F to 80°F, higher relative humidity, higher [corrected] wind speed, more precipitation, greater population density, and [corrected] periods during which schools were open.
  
  
  CONCLUSIONS
  Hand, foot, and mouth disease is a moderately transmittable infectious disease, mainly among preschool children. Enterovirus 71 was responsible for most severe cases and fatalities. Mixing of asymptomatically infected children in schools might have contributed to spread the of infection. Timely diagnosis may be [corrected] key to reducing the high mortality rate in infants.
authors.affiliation: Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Zijian
authors.initials: Z
authors.lastname: Feng
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Steve
authors.initials: S
authors.lastname: Self
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Gao
authors.forename: Ira M
authors.initials: IM
authors.lastname: Longini
authors.forename: Jon
authors.initials: J
authors.lastname: Wakefield
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Lena
authors.initials: L
authors.lastname: Yao
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Stanaway
authors.forename: Zijun
authors.initials: Z
authors.lastname: Wang
authors.forename: Weizhong
authors.initials: W
authors.lastname: Yang
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D057210:Delayed Diagnosis / Q000706:statistics & numerical data; D004196:Disease Outbreaks / Q000706:statistics & numerical data; D029821:Enterovirus A, Human / Q000472:pathogenicity; D005260:Female; D006232:Hand, Foot and Mouth Disease / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D006801:Humans; D007223:Infant; D008297:Male; D011159:Population Surveillance; D012307:Risk Factors; D012621:Seasons; D012720:Severity of Illness Index; D012737:Sex Factors