Hepatitis E virus: epidemiological, clinical and serological studies of north Indian epidemic

A large waterborne epidemic of viral hepatitis occurred in the city of Karnal (Haryana) from February to April 1987. An attempt was made to study the epidemic clinically, serologically and etiologically.

A house-to-house search of the city was conducted for the detection of acute hepatitis cases. Patients willing to give blood samples for liver function tests were studied.

A total of 1273 persons (0.79% of persons surveyed) were affected by viral hepatitis. Of the 477 clinically and biochemically documented cases, more than 75% were adults, while only 11% were less than 10 years old. Children below 15 years of age and females had a significantly higher incidence of anicteric hepatitis. Serological markers for acute hepatitis A and B viruses were absent in 85% of patients. Antibodies to hepatitis E virus (HEV) were detected in 84% of acute phase sera studied by indirect immunofluorescence assay. Liver biopsy showed characteristic features of cholangitic hepatitis. Three of 19 pregnant females who developed hepatitis died. No residual clinical or biochemical abnormality was detected in any of the patients followed up for 8 months. This epidemic correlated with the timing of unsupervised digging of lanes to provide new tap water connections to houses in the congested area of the city. This resulted in damage to the sewerage system and leakages which contaminated drinking water supply.

HEV was transmitted by contaminated drinking water in this epidemic. Most affected individuals were adults, and recovered without sequelae. Affected pregnant women had a worse outcome.