HEPATITIS VIRUSES: OLD AND NEW MEMBERSHIP

Key words: Hepatitis A, Hepatitis D, Hepatitis E, Hepatitis G

The incidence of hepatitis A has recently increased in Italy, the majority of cases being adolescents or young adults living in southern Italy. Shellfish consumption and travel to endemic areas are the main risk factors associated to an increased risk for HAV infection. Hepatitis D endemicity is decreased in Italy probably as a consequence of the decreased pool of HBsAg chronic carriers, the reduced family size, the improved socio-economic conditions and the changes of intravenous drug abuser behaviour. Hepatitis E virus is a single stranded RNA virus. The virus is transmitted from contaminated drinking water. Fulminant hepatitis may occur in 0.5 to 3% of cases, but in pregnant women, it may reach 15 to 25%. Vertical transmission appears to be frequent with occasional occurence of fatal forms. Diagnosis is made by detection of IgM and IgG by current ELISA tests. Recombinant vaccines are currently beig tested in animals. GBV-C and hepatitis G virus are an unique virus recently described. HGV may infect humans and the presence of HGV-RNA in serum by polymerase chain reaction demonstrates the infection. HGV-RNA may be also found in healthy individuals. Current evidence suggest that the virus is probably harmless.