Hepatitis C Virus
Hepatitis C virus (HCV) is an enveloped, positive-sense single-stranded RNA virus of the family Flaviviridae. It consists of a core of genetic material surrounded by an icosahedra protective shell of protein. The genome consists of a single open reading frame that is 9600 nucleotide bases long.
HCV replication takes several steps. It primarily replicates in the hepatocytes of the liver. It can also reproduce in peripheral blood mononuclear cells. There is a wide variety of genotypes and it mutates rapidly due to a high error rate on the part of the virus’ RNA. HCV takes over portions of the intracellular machinery to replicate. The genome is then translated to produce a single protein of around 3011 amino acids.
Diagnosis occurs via DNA analysis of the 5′-noncoding region. Results may vary depending on genotype and viral load. Hepatitis C virus species is classified into six genotypes with several subtypes. Infection of one genotype will not provide immunity against others. There is no current vaccination to prevent hepatitis C infection.
Studies started in 2006 were 60 patients received a vaccination and all produced antibodies that were believed to potentially protect them from the virus. By 2008 the tests were still ongoing. Current research is focused on small-molecule inhibitors of the viral protease and RNA polymerase. Due to the narrow host range of HCV the studies have been slow.
Simple physical reduction in circulating HCV using a one week pretreatment of the patients’ blood using a Double-filtration plasmapheresis technique increased the cure rate for treatment-naÃ¯ve type 1 HCV patients from 50% to 78%.