Non‐ABCDE hepatitis: IS there another enterically transmitted hepatitis virus?

Many epidemics of water‐borne hepatitis have occurred throughout India. These were thought to be epidemics of hepatitis A until 1980, when evidence for an enterically transmitted non‐A, non‐B hepatitis was first reported. Subsequently, hepatitis E virus was discovered and most recent epidemics of enterically transmitted non‐A, non‐B hepatitis have been attributed to hepatitis E virus infection. However, only a limited number of cases have been confirmed by immuno electron microscopy, polymerase chain reaction, or seroconversion. In the present study we have performed a retrospective seroepidemiologic study of 17 epidemics of water‐borne hepatitis in India. We have confirmed that 16 of the 17 epidemics were caused at least in part by serologically closely related hepatitis E viruses. However, one epidemic, in the Andaman Islands, and possibly a significant minority of cases in other epidemics, appears to have been caused by a previously unrecognized hepatitis agent.