Background: Shimla city has been observing outbreak of hepatitis A/E every year since 2007. An unusual rise in the number of jaundice cases was reported in the first fortnight of December 2015. Objectives: To study the distribution and determinants of hepatitis cases, to find the source of infection, and to initiate the control measures in the affected area. Materials and Methods: A case of acute hepatitis was defined as a person who had acute jaundice with at least one of the following symptom: dark urine, anorexia, malaise, fatigue and right upper quadrant tenderness between December 2015 and March 2016. Line listing of cases was done and analyzed according to time, place, and person distribution. Blood samples were tested for IgM antibody for hepatitis A & E virus. Water samples were also collected for the bacteriological examination and residual chlorine. Results: A total of 6080 cases (attack rate 35.9/1000) were reported in this outbreak. 1132 serum sample were found positive for HEV IgM antibodies out of 1988 samples tested randomly, which confirmed a hepatitis E outbreak. The attack rate was significantly higher in males (P < 0.05) and in age groups 25-34 years (P < 0.001). Case fatality rate was found to be 0.4% among general population and 21% among pregnant females. Extensive IEC was done through electronic and print media. More than one lakh chlorine tablets were distributed. Environmental investigation confirmed sewage contamination of drinking water. All 6 STP were found to be working sub optimally. Ineffective chlorination was found at all 4 WTP. The relative risk of developing hepatitis E among people using contaminated water supply against those using other sources was 5.68 (95% CI 4.81 , 7.14). Conclusion: HEV was confirmed as the major etiological agent in this outbreak which was transmitted by contaminated drinking water. Keywords: Epidemiological investigation, Hepatitis E, Attack Rate, Relative Risk, Serological examination.
Corresponding author: Dr. Amit Sachdeva, Junior Resident, Department of Community Medicine, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
This article may be cited as: Thakur A, Rao R, Sachdeva A. Epidemiological Investigation of Hepatitis E outbreak in a Northern city of India. J Adv Med Dent Scie Res 2017;5(8):29-36.