Epidemiology of hepatitis C virus infection in Australia

The geographical distribution of chronic hepatitis C virus (HCV) infection appears to be one of high and low prevalence regions. Australia resembles the USA, UK and other parts of northern Europe in being a low prevalence region, and thereby differs from southern Europe, the middle-east, south-eastern Asia and Japan. However, the high levels of recent immigration from areas with high prevalence of chronic HCV infection makes Australia an interesting place for epidemiological studies of hepatitis C. In particular, it is possible to examine different pathways of viral transmission and any pathobiological differences liver disease related to the source of infection. A further implication of recent immigration is that the genetic diversity of the Australian population is increasing. Thus 24% of the present population were born outside Australia, including in southern European, middle-eastern and southeast Asian countries. This has allowed us to reexamine the proposed relationships between HCV infection and autoimmune chronic active hepatitis within a genetically heterogeneous community. In the present minireview, we have examined the published as well as preliminary unpublished data concerning the prevalence of chronic HCV infection in Australia. In particular, we discuss the risks of viral infection according to parenteral and nonparenteral modes of spread, the relationship of these and other demographic factors to the severity of associated hepatic pathology, and the serological and virological correlates of autoimmune and hepatitis C-related liver disease.