What is hepatitis C virus?

Hepatitis C virus, or HCV, is a small, enveloped, positive-sense, single-stranded RNA virus of the family Flaviviridae. HCV causes hepatitis C infection in humans. HCV is contagious when blood-to-blood contact occurs, and the disease primarily affects the liver.

HCV infection may be acute or chronic. Symptoms of acute disease are usually mild and include decreased appetite, fatigue, muscle or joint pains, nausea and weight loss. Jaundice does not usually occur with mild disease. HCV resolves spontaneously in approximately 10% to 50% of cases.

Chronic infection occurs in about 80% of patients with HCV. Chronic disease may be asymptomatic or be associated with only mild fatigue for decades. However, after many years, damage to the liver can cause cirrhosis or liver cancer. Frequent alcohol consumption, hepatitis B or HIV infection, and male gender are linked to increased risk for cirrhosis among those with HCV.

The most common mode of transmission in the developed world is IV drug use; in the developing world, HCV is usually transmitted via blood transfusions or other unsafe medical procedures. The disease may also be transmitted through body piercings or other shared sharp personal items. Vertical transmission — from mother to child through birth or the fetal development process — also may occur. The medical community is in disagreement about whether HCV can be transmitted sexually. Some believe that it occurs, whereas others believe that poor sexual health habits are practiced by many injection drug users, rendering it difficult to pinpoint whether the drug use or the sexual contact caused the infection.

HCV may be diagnosed by one of a number of assays that detect antibodies or other abnormalities in the body that signify infection. Current diagnostic tools are not able to distinguish between chronic and acute infection. A biopsy may be used to measure damage to the liver.

The Centers for Disease Control and Prevention (CDC) estimates that only 5% to 50% of infected people in the United States and Canada are aware of their infection. Screening is recommended for those at high risk, including those who use injection drugs or have tattoos.

There is no vaccine for HCV. Although there are no primary prevention measures, infection may be prevented by employing safe drug use habits and only getting piercings or tattoos at sanitary locations. Broader prevention measures include harm reduction policies and screening blood donors.

A combination of pegylated interferon alfa and the antiviral drug ribavirin for 24 or 48 weeks is generally used to treat HCV. This treatment has a success rate of 40% to 80%.

Additional information about HCV may be found at these websites:

http://www.nlm.nih.gov/medlineplus/hepatitisc.html

http://www.ncbi.nlm.nih.gov/books/NBK1613/

http://www.cdc.gov/hepatitis/

http://www.who.int/csr/disease/hepatitis/whocdscsrlyo2003/en/index2.html

http://www.who.int/mediacentre/factsheets/fs164/en/index.html

http://www.cdc.gov/hepatitis/HCV/index.htm