title: Epidemiological investigation of an outbreak of hepatitis A in rural China.
abstract: OBJECTIVE
  This investigation was a response to an outbreak of hepatitis A in rural China in 2013. The objectives were to identify the pattern of transmission and the risk factors.
  
  
  METHODS
  A probable case was defined as an individual in/nearby the village of the outbreak with jaundice and/or an elevation of serum alanine aminotransferase (at or above 80 IU/l) plus at least three of the following symptoms: fever (axillary temperature ≥37 °C), headache, nausea, vomiting, anorexia, or abdominal pain in the upper right quadrant, during the outbreak period (from June 1 to August 11, 2013). Using a case-control study design, we compared exposures to suspected food items, water, and close contact with a patient or case with asymptomatic infection between 22 cases and 32 controls.
  
  
  RESULTS
  We identified 22 cases, including 15 symptomatic cases and seven with asymptomatic infections. All cases were aged <15 years. Household clustering was apparent (Chi-square=4.69, p<0.05). Contact with symptomatic cases or cases with an asymptomatic infection was a major risk factor (59.09% in cases and 25.00% in the controls: odds ratio (OR) 4.33, 95% confidence interval (CI) 1.17-16.68). A good hand-washing habit (at least once per day) was found in 45.45% of cases vs. 78.13% of controls (OR 0.23, 95% CI 0.06-0.88). The dose-response analysis showed that the daily frequency of hand-washing was inversely associated with infection (trend Chi-square=5.35, p=0.021). Person-to-person transmission was deduced from the epidemic curves and the transmission chain of symptomatic cases.
  
  
  CONCLUSIONS
  The pattern of transmission in this outbreak was person-to-person, and the transmission route was indicated to be fecal-oral. In addition to close contact, insufficient hand-washing was a risk factor. Strengthening the management of the rural environmental sanitation services and enhancing awareness in the household are key to preventing outbreaks of hepatitis A in the future.
authors: Jiangxi Center for Disease Control and Prevention, Nanchang, People's Republic of China.
authors: Ping
authors: P
authors: Yu
authors: Nanjing Medical University, Nanjing, People's Republic of China.
authors: Lihong
authors: L
authors: Huang
authors: Nanchang Center for Disease Control and Prevention, Nanchang, People's Republic of China.
authors: Hui
authors: H
authors: Li
authors: Nanchang Center for Disease Control and Prevention, Nanchang, People's Republic of China.
authors: Mingbin
authors: M
authors: Liu
authors: Jiangxi Center for Disease Control and Prevention, Nanchang, People's Republic of China.
authors: Jun
authors: J
authors: Zong
authors: Tianjin Center for Disease Control and Prevention, Tianjin, People's Republic of China.
authors: Chao
authors: C
authors: Li
authors: Nanjing Medical University, Nanjing, People's Republic of China. Electronic address: fengchen@njmu.edu.cn.
authors: Feng
authors: F
authors: Chen
mesh_terms: D000293:Adolescent; D058345:Asymptomatic Infections; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks / Q000517:prevention & control; D062665:Epidemiological Monitoring; D005260:Female; D006235:Hand Disinfection; D006506:Hepatitis A / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012307:Risk Factors; D012424:Rural Population
keywords: Case–control study; Hepatitis A; Outbreak; Person-to-person transmission