Virology, diagnostic tests, epidemiology and transmission

Abstract

The hepatitis C virus is a human virus, classified within a third type (Hepacivirus) of the Flaviviridae family. It is a spherical virus, of approximately 50 nm in diameter, with a glycoprotein covering that contains lipids, and its genome is a simple chain RNA molecule. It is characterised by a high degree of genomic heterogeneity, whose evolutionary consequence in the long term is the appearance of genetically different viral groups, genotypes and quasispecies. There are different diagnostic techniques for detecting hepatitis C virus infection. Serological assays: the detection of specific IgG against HCV by means of enzyme immunoassays is the most practical method for diagnosing infection by this virus. Supplementary immunblot tests are employed to confirm the specificity of the results of the EIA test. Molecular assays: qualitative and quantitative techniques have been developed for detecting RNA-HCV, based on the direct detection of the virions. The pathogeny of hepatitis C is not well understood. Its world prevalence is estimated at some 3%, which is why routine screening for its detection is not recommended. HCV transmission basically occurs through percutaneous exposure to infected blood, with higher rates observed in imprisoned persons, vagabonds, intravenous drug addicts, haemophiliacs and patients on haemodialysis. Although it can be transmitted sexually, it seems that this path is not very efficient, with a greater prevalence observed in persons with multiple sexual partners. Vertical transmission is estimated at some 2%, reaching 20% in cases of maternal coinfection with HIV.