Investigation of viral hepatitis E outbreak in a town in Haryana.

An outbreak of 160 cases of viral hepatitis which occurred in Shahbad, Haryana, was investigated to ascertain the agent, cause of the outbreak and to initiate remedial measures. Out of the 30 samples tested, 26 (86.7%) were positive for IgM antibody against HEV, establishing hepatitis E virus responsible for the outbreak. Significant association of higher attack rates (4%) in ward 14 (OR = 17.9; 95% CI = 12.7-25.2) of the town along with leakage in water distribution system running co-existent with open drains containing household waste and sewage; and absence of residual chlorine in water samples tested at household level in ward 14 established fecal contamination of water as the cause of the outbreak. Remedial repair work was initiated along with superchlorination of water which contained the outbreak.