Hepatitis
Delta Virus (HDV) infections always occur in association with hepatitis B virus
(HBV) infections because of their dependence upon the HBV. The hepatitis delta
virion is composed of an outer lipoprotein envelope made of the surface antigen
of HBV (HBsAg) and an inner ribonucleoprotein structure in which the HDV genome
resides . Due to the dependence of HDV on HBV, the presence of HBsAg is
necessary for the diagnosis of HDV infection.HDV causes both acute and chronic
infections. Asymptomatic and non-progressive illnesses are seen in a minority
of cases, but a severe and progressive route to cirrhosis is present in most.
Available data suggest that approximately 5% of HBV carriers worldwide may beinfected with HDV; it is estimated that there are 18-20 million people
chronically infected with HDV worldwide. However, the epidemiologic
distribution of HDV infection does not parallel that of HBV, because areas
endemic for HBV may be almost HDV free. The level of HDV endemicity is partly
related to the route of transmission.
HDV
infections are common in Southeast Asia, Eastern Europe, and South American
countries; however, it is seldom found in the United States of America and
parts of Europe . Nevertheless, after a dramatic decrease in the seroprevalence
of HDV infections in Europe, studies have shown that the seroprevalence of
anti-HD in Italy among HBsAg carriers is again similar to that found in 1997
(9.7%). The virus has remained endemic in the Middle East, Central Africa, Mongolia,
Tajikistan, and northern parts of South America, but data are lacking from many
areas where hepatitis B is highly prevalent. Read more.............
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