Hepatitis C: A sobering look at an elusive virus
Anatomy of hepatitis C
One of the most critically dangerous aspects of the hepatitis C virus is that it is stored in the RNA, not the DNA of the victim. The structure of the hepatitis C virus takes the form of a core of RNA surrounded by a protective shell of protein encased in a fatty envelope of cellular material. In contrast to the relatively stable DNA molecule, RNA is a quite volatile and makes frequent mistakes during the replication process, averaging one mistake per 10,000 nucleotides each time it is copied. This makes mutation quite common and treatment quite difficult. The viral RNA is read by the host cell’s ribosomes, “functioning like the normal mRNA present in the cell. The virus thus needs no special abilities of its own – it uses the cell’s own ribosomes to produce everything it needs for its takeover of the cell’s processes and reproduction. This means hepatitis C requires only a small amount of RNA to encode its core information, and thus has lots of room for genetic variation within the non-essential portions of its RNA. This also gives it fewer common characteristics that can be readily identified by the immune system – or, for that matter, exploited by scientists working to create a treatment” (Hepatitis C, 2009, Dartmouth Medical School).
Hepatitis C has been called a “moving target” because of its ability to mutate (O’Shea 2009). Although it only replicates in the hepatocytes, it can be found in many areas of the body, including the liver, peripheral blood mononuclear cells, dendritic cells, epithelium, and even the central nervous system. “Viral replication occurs through an RNA-dependent RNA polymerase process. Lymphocytes recognize infected cells and initiate an immune response to control the virus. Viral clearance is associated with the development and persistence of strong, virus-specific responses by cytotoxic T. lymphocytes and helper T cells. Because of the rapid evolution of diverse quasispecies within an infected person,” even a shift antibody response to hepatitis C often cannot combat the infection (O’Shea 2009). Persistent inflammation in the liver can lead to progressive hepatic fibrosis and cirrhosis.
During its earliest stages, many individuals have no signs. During the incubation period, which can last from several weeks to several months, some patients may experience weight loss, fatigue, muscle pain or joint pain, irritability, nausea, malaise, anorexia, jaundice, itchiness, and difficulty with concentration (O’Shea 2009). As the liver damage progresses, these symptoms may grow more severe. “The hepatitis C virus is linked to an increased risk of porphyria cutanea tarda, a condition that may cause a blistering rash, to cryoglobulinemia, which can cause a purplish rash (purpura) onâ€¦lower extremities, and may cause kidney damage” (Complications, 2009, The Mayo Clinic).
Many patients have no specific symptoms and the finding of abnormal hepatic transaminase levels on routine testing is what often prompts specific testing for hepatitis C (O’Shea 2009). Blood tests or a liver biopsy to determine the severity of the illness are usually used by doctors. “If test results indicate that you have HCV, your doctor may measure the quantity of the virus in your blood (viral load) and evaluate the genetic makeup of the virus (genotype). There are six known HCV genotypes. Knowing which genotype you have will help your doctor determine the best course of treatment for you and how likely you are to respond to treatment” (Tests and diagnosis, 2009, The Mayo Clinic).
Because hepatitis C can be spread through sexual contact, it is critical that the infected individual receive notice that he or she is a carrier as soon as possible, and work with doctors to take precautions regarding his or her sexual partners. Hepatitis C patients should be monitored for the risk of developing lymphatic system cancers, for which they are at increased risk. Aggressive treatments for Hepatitis C can include drug treatment or liver transplants, but for some relatively asymptomatic patients, doctors may recommend abstaining from alcohol consumption to reduce the strain on the liver, avoiding liver-damaging medications such as acetaminophen, and constant monitoring (Treatment, 2009, The Mayo Clinic).
Complications. (2009). Hepatitis C The Mayo Clinic. Retrieved April 22, 2009 at http://www.mayoclinic.com/health/hepatitis-c/DS00097/DSECTION=complications
Hepatitis C: An epidemic for anyone. (2009). Dartmouth Medical School. Retrieved April 22,
2009 at http://www.epidemic.org/theFacts/hepatitisC/anatomy/
O’Shea, Robert. (2009). Hepatitis C The Cleveland Clinic. Retrieved April 22, 2009 at http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/hepatology/hepatitis-C/#cesec2
Tests and diagnosis. (2009). Hepatitis C The Mayo Clinic. Retrieved April 22, 2009 at http://www.mayoclinic.com/health/hepatitis-c/DS00097/DSECTION=tests-and-diagnosis
Treatments. (2009). Hepatitis C The Mayo Clinic. Retrieved April 22, 2009 at http://www.mayoclinic.com/health/hepatitis-c/DS00097/DSECTION=treatments-and-drugs