Epidemiology and Geographical Distribution

Infection with HCV occurs throughout the world. Much of the seroprevalence data are based on blood donors, who represent a selected population. The prevalence of antibodies to HCV in blood donors varies from 0.02% to 1.25% in different countries. Higher rates have been found in southern Italy, Spain, central Europe, Japan and parts of the Middle East, with as many as 19% in Egyptian blood donors. Until screening of blood donors was introduced, hepatitis C accounted for the vast majority of non-A, non-B post-transfusion hepatitis. However, it is clear that, while blood transfusion and the transfusion of blood products are efficient routes of transmission of HCV, these represent a small proportion of cases of acute clinical hepatitis in a number of countries (with the exception of patients with haemophilia).

Current data indicate that, in 50% or more of patients in industrialised countries, the source of infection cannot be identified; although transmission by contact with blood and contaminated materials is likely to be important, 35% of patients have a history of intravenous drug misuse. Household contact and sexual exposure do not appear to be major factors in the epidemiology of this common infection, and occupational exposure in the health care setting accounts for about 2% of cases. Transmission of HCV from mother to infant occurs in about 10% of viraemic mothers and the risk appears to be related to the level of viraemia. It should be noted, however, that information on the natural history of hepatitis C is limited because the onset of the infection is often unrecognised and the early course of the disease is indolent and protracted in most patients. Coinfection with HBV is not uncommon.

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