Epidemiology and Diagnosis of Hepatitis D Virus

The distribution of hepatitis D virus (HDV) is worldwide but not uniform. Current estimates suggest that 15–20 million people have exposure to HDV. Traditionally, areas of high prevalence are the Mediterranean basin, the Middle East, central Africa, the Amazonian basin and parts of Asia. As a consequence of vaccination against HBV and other prophylactic measures, the prevalence of HDV declined in Italy, Spain, Turkey and Taiwan. This downward trend stopped in the 1990s; a new location for HDV epidemics arose in western Europe, due to migration from endemic areas. HDV appeared in new geographic regions, posing a serious health threat in underdeveloped countries. Testing for anti-HVD antibodies in serum is the initial step in diagnosing HDV infection, but unravelling HDV RNA is essential to identify active replication.