Kolkata: Hepatitis D is a liver disease in both acute and chronic forms caused by the hepatitis D virus (HDV) that requires hepatitis B virus (HBV) for its replication.
Hepatitis D infection cannot occur in the absence of hepatitis B virus. The coinfection or super infection of HDV with HBV causes a more severe disease than HBV monoinfection. According to World Health Organization (WHO), a vaccine against hepatitis B is the only method to prevent HDV infection.
It is estimated that globally, 5 per cent of HBsAg positive people are coinfected with HDV and the distribution is worldwide. High-prevalence areas include the Mediterranean, Middle East, Pakistan, Central and Northern Asia, Japan, Taiwan, Greenland and parts of Africa (mainly the horn of Africa and West Africa), the Amazon Basin and certain areas of the Pacific. Prevalence is low in North America and Northern Europe, South Africa, and Eastern Asia.
The routes of HDV transmission are the same as for HBV: percutaneously or sexually through contact with infected blood or blood products. Vertical transmission is possible but rare. Vaccination against HBV prevents HDV coinfection, and hence expansion of childhood HBV immunization programmes has resulted in a decline in hepatitis D incidence worldwide.
However, in some settings, the increase of hepatitis D prevalence has been observed in people who inject drugs, or as a result of migration from areas where HDV is endemic.
Acute hepatitis: simultaneous infection with HBV and HDV can lead to a mild-to-severe or even fulminant hepatitis, but recovery is usually complete and development of chronic hepatitis D is rare (less than 5 per cent of acute hepatitis).
Superinfection: HDV can infect a person already chronically infected with HBV. The superinfection of HDV on chronic hepatitis B accelerates progression to a more severe disease in all ages and in 70?90 per cent of persons. (UNI)