Hepatitis C, the major liver debilitating virus.


Until the causative agent of hepatitis C infection, i.e. hepatitis C virus (HCV), was identified in 1989, hepatitis C was known as a viral infection of the liver which was thought to be parentally transmitted non-A, and non-B hepatitis. HCV is a major cause of acute hepatitis and chronic liver disease such as cirrhosis and liver cancer. HCV is an RNA virus with envelope and belongs to flaviviridae family, and has a narrow host range as known to infect only humans and chimpanzees leading to similar liver diseases.

No vaccine is currently available to prevent hepatitis C. The onset of symptoms become evident after 15-150 days of incubation period after infection. The symptoms of hepatitis C virus infection includes fatigue and jaundice. However, the majority of the infections (60-70%) are asymptomatic. About 80% of the infections will progress to chronic stage, of which about 10-20% develop liver cirrhosis. About 1-5% of chronic infections over the period of 20-30 years develop liver cancer. Most of non-HBV patients with liver cancer turn out to be HCV carrier. HCV exacerbate the liver disease when combined with other hepatitis viruses and hepatic conditions such as alcoholic liver disease.

HCV is mainly spread through direct contact involving human blood. HCV is not known to be transmitted by sneezing, hugging, food and water, sharing eating utensils, or casual contact. The mechanism of HCV action is not clearly known. WHO estimates that about 3% of the world's population, or 170 million people are infected with HCV and are at risk of developing liver cirrhosis and cancer. HCV is more popular in developing countries in Africa (5.3%), eastern Mediterranean (4.6%), southeast Asia (2.15%) and the western Pacific (3.9%) than North America (1.7%) and Europe (1.03%). An estimated 3-4 million people are newly infected by HCV worldwide.

Diagnosis of HCV infection is conducted through commercially available enzyme immunosorbant assays (EIA) that detects hepatitis C specific antibodies. Over 95% of chronic HCV infections are detected by EIA, while only 50-70% of acute infections can be detected by this method. As a supplemental test, recombinant immunoblot assay (RIBA) is used. More sensitive assays based on polymerase chain reactions (PCR) is also used to detect the presence of the viral nucleic acid.

Antiviral interferon alone, or combination of interferon and ribavirin are used for the treatment of hepatitis C. The methods are only marginally effective (10-20% success rate for interferon alone, and 30-50% success rate for combination treatment), and the cost high.