Microbiology
Summary
The hepatitis C virus (HCV), a member of the Flaviviridae family, is an enveloped virus with positive-sense, single-stranded, non-segmented RNA. The RNA dependent RNA polymerase of HCV lacks proofreading exonuclease activity, leading to frequent mutations and antigenic variation. HCV can be transmitted through shared needles, blood transfusions, and other routes.
In acute HCV infection, fluctuating ALT levels can be observed, while chronic infection may progress to cirrhosis and hepatocellular carcinoma. HCV infection is detected using both an HCV antibody test and an HCV RNA test (PCR), with a positive HCV RNA test indicating active infection. A negative HCV antibody test with a positive RNA test suggests occult HCV infection. Direct-acting antivirals are effective treatments for HCV. When treating HCV, ensure patients are vaccinated for hepatitis A and B unless already immune. For chronic HCV patients, regular monitoring of serum alpha-fetoprotein and liver ultrasounds is recommended to monitor for hepatocellular carcinoma.
Lesson Outline
Don't stop here!
Get access to 128 more Microbiology lessons & 13 more medical school learning courses with one subscription!
FAQs
The hepatitis C virus (HCV) is a virus that causes hepatitis (inflammation of the liver). It belongs to the Flaviviridae family of viruses, which also includes viruses that cause diseases such as Zika, dengue fever, and West Nile fever. Like other viruses in this family, HCV is a positive-sense RNA virus, meaning its genome can be directly translated into viral proteins.
The hepatitis C virus is primarily transmitted through direct blood-to-blood contact. This can occur through sharing needles, syringes, or any other equipment to inject drugs, receiving unscreened blood transfusions or organ transplants, or through non-sterile medical or cosmetic procedures. Less commonly, it can be transmitted vertically from mother to child, or through sexual contact.
Acute hepatitis C refers to the first 6 months after infection with HCV. Many people exhibit no symptoms during this stage. Some people will clear the virus from their bodies without treatment, but for most people, the acute phase transitions into a long-term infection known as chronic hepatitis C. This stage can last a lifetime and lead to serious liver problems, including cirrhosis (scarring of the liver) or hepatocellular carcinoma (a type of liver cancer).
Hepatitis C is typically diagnosed through a two-step process: an initial antibody test to see if a person has been exposed to the virus, followed by a hepatitis C RNA PCR test to detect the presence of the virus itself and measure the quantity of virus in the blood. This second test is also used to monitor the effectiveness of treatment.
Treatment for hepatitis C involves the use of direct-acting antivirals (DAAs), drugs that target specific steps in the HCV lifecycle. These can often cure the disease, though certain strains of the virus may exhibit antigenic variation, making them resistant to certain treatments.
