Hepatitis C virus: molecular virology and its implications for serologic diagnosis.
Hepatitis C Virus (HCV) has been identified as the major etiological agent of parenterally-transmitted non-A non-B hepatitis. The virus has been cloned recently and completely or partially sequenced. Molecular analysis of the HCV genome indicates that it is a small, enveloped RNA virus having a highly conserved structural region followed by five less conserved non-structural regions. Based on nucleotide sequences, it has been found that multiple types of HCV exist. Infection with HCV can now be diagnosed by using virus-specific antibodies. A first generation enzyme-linked immunosorbent assay (ELISA) was initially used. However, this test had many drawbacks and consequently a second generation ELISA has been developed. The inclusion of new antigens in a recombinant immunoblot assay has further increased the sensitivity of diagnosing HCV infection. Also, detection of the virus genetic material by using polymerase chain reaction has enabled detection of viremia within only a few days following exposure apart from offering a possibility to monitor anti-viral treatment, since a decrease in viral RNA level is noticed in patients with positive response to treatment.
Ramia
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Department of Pathology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.