Epidemiological investigation of an outbreak of hepatitis A in rural China

Abstract

Objectives: 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