The hepatitis C virus (HCV) is spread by blood-to-blood contact with an infected person's blood. While the symptoms can be medically managed, there are no curative treatements. Although modification of diet and early medical intervention are helpful, people with HCV infection often experience mild symptoms, and subesquently do not seek treatment. An estimated 150-200 million people worldwide are infected with hepatitis C. In the U.S., those with a history of intravenous drug use, tattoos, or who have been exposed to blood via unsafe sex or social practices are high risk for this disease. Hepatitis C is the leading cause of liver transplant in the United States. Cirrhosis of the liver and liver cancer may ensue from Hepatitis C.
In the mid 1970s, Harvey J. Alter, Chief of the Infectious Disease Section in the Department of Transfusion Medicine at the National Institutes of Health (NIH), and his research team demonstrated that most post-transfusion hepatitis cases were not due to hepatitis A and B viruses. Despite this discovery, international research effort to identify the virus, initially called non-A, non-B hepatitis (NANBH), failed for the next decade. In 1987, Michael Houghton, Qui-Lim Choo, and George Kuo at Chiron Corporation utilized molecular cloning to identify the unknown organism. In 1988, the virus was confirmed by Alter by verifying its presence in a panel of NANBH specimens. In April of 1989, the discovery of the virus, re-named hepatitis C virus (HCV), was published in two articles in the journal Science.
Signs and Symptoms
Acute Hepatitis C:Acute hepatitis C refers to the first 6 months after infection with HCV. Between 60% to 70% of people infected develop no symptoms during the acute phase. In the minority of patients who experience acute phase symptoms, they are generally mild and nonspecific, and rarely lead to a specific diagnosis of hepatitis C. Symptoms of acute hepatitis C infection include decreased appetite, fatigue, abdominal pain, jaundice, itching, and flu-like symptoms.
The hepatitis C virus is usually detectable in the blood within one to three weeks after infection, and antibodies to the virus are generally detectable within 3 to 12 weeks. Approximately 20-30% of persons infected with HCV clear the virus from their bodies during the acute phase as shown by normalization in liver function tests (LFTs) such as alanine transaminase (ALT) & aspartate transaminase (AST) normalization, as well as plasma HCV-RNA clearance (this is known as spontaneous viral clearance). The remaining 70-80% of patients infected with HCV develop chronic hepatitis C, i.e., infection lasting more than 6 months.
Previous practice was to not treat acute infections to see if the person would spontaneously clear; recent studies have shown that treatment during the acute phase of genotype 1 infections has a greater than 90% success rate with half the treatment time required for chronic infections, but that the majority of acute hepatitis C is cleared. 
Chronic Hepatitis C:Chronic hepatitis C is defined as infection with the hepatitis C virus persisting for more than six months. Clinically, it is often asymptomatic (without jaundice) and it is mostly discovered accidentally.
The natural course of chronic hepatitis C varies considerably from one person to another. Virtually all people infected with HCV have evidence of inflammation on liver biopsy, however, the rate of progression of liver scarring (fibrosis) shows significant variability among individuals. Recent data suggests that among untreated patients, roughly one-third progress to liver cirrhosis in less than 20 years. Another third progress to cirrhosis within 30 years. The remainder of patients appear to progress so slowly that they are unlikely to develop cirrhosis within their lifetimes. Factors that have been reported to influence the rate of HCV disease progression include age (increasing age associated with more rapid progression), gender (males have more rapid disease progression than females), alcohol consumption (associated with an increased rate of disease progression), HIV coinfection (associated with a markedly increased rate of disease progression), and fatty liver (the presence of fat in liver cells has been associated with an increased rate of disease progression).
Symptoms specifically suggestive of liver disease are typically absent until substantial scarring of the liver has occurred. However, hepatitis C is a systemic disease and patients may experience a wide spectrum of clinical manifestations ranging from an absence of symptoms to debilitating illness prior to the development of advanced liver disease. Generalized signs and symptoms associated with chronic hepatitis C include fatigue, marked weight loss, flu-like symptoms, muscle pain, joint pain, intermittent low-grade fevers, itching, sleep disturbances, abdominal pain (especially in the right upper quadrant), appetite changes, nausea, diarrhea, dyspepsia, cognitive changes, depression, headaches, and mood swings.
Once chronic hepatitis C has progressed to cirrhosis, signs and symptoms may appear that are generally caused by either decreased liver function or increased pressure in the liver circulation, a condition known as portal hypertension. Possible signs and symptoms of liver cirrhosis include ascites (accumulation of fluid in the abdomen), bruising and bleeding tendency, bone pain, varices (enlarged veins, especially in the stomach and esophagus), fatty stools (steatorrhea), jaundice, and a syndrome of cognitive impairment known as hepatic encephalopathy.
Liver function tests show variable elevation of ALAT, AST and GGTP and periodically they might show normal results. Usually prothrombin and albumin results are normal.
The diagnosis of hepatitis C is rarely made during the acute phase of the disease because the majority of people infected experience no symptoms during this phase of the disease. Those who do experience acute phase symptoms are rarely ill enough to seek medical attention. The diagnosis of chronic phase hepatitis C is also challenging due to the absence or lack of specificity of symptoms until advanced liver disease develops, which may not occur until decades into the disease.
Chronic hepatitis C may be suspected on the basis of the medical history, a history of piercings or tattoos, unexplained symptoms, or abnormal liver enzymes or liver function tests found during routine blood testing. Occasionally, hepatitis C is diagnosed as a result of targeted screening such as blood donation (blood donors are screened for numerous blood-borne diseases including hepatitis C) or contact tracing.
Hepatitis C testing begins with serological blood tests used to detect antibodies to HCV. Anti-HCV antibodies can be detected in 80% of patients within 15 weeks after exposure, in >90% within 5 months after exposure, and in >97% by 6 months after exposure. Overall, HCV antibody tests have a strong positive predictive value for exposure to the hepatitis C virus, but may miss patients who have not yet developed antibodies (seroconversion), or have an insufficient level of antibodies to detect. While uncommon, a small minority of people infected with HCV never develop antibodies to the virus and therefore, never test positive using HCV antibody screening.
Anti-HCV antibodies indicate exposure to the virus, but cannot determine if ongoing infection is present. All persons with positive anti-HCV antibody tests must undergo additional testing for the presence of the hepatitis C virus itself to determine whether current infection is present. The presence of the virus is tested for using molecular nucleic acid testing methods such as polymerase chain reaction (PCR), transcription mediated amplification (TMA), or branched DNA (b-DNA). All HCV nucleic acid molecular tests have the capacity to detect not only whether the virus is present, but also to measure the amount of virus present in the blood (the HCV viral load). The HCV viral load is an important factor in determining the probability of response to interferon-base therapy, but does not indicate disease severity nor the likelihood of disease progression.
In people with confirmed HCV infection, genotype testing is generally recommended. There are six major genotypes of the hepatitis C virus, which are indicated numerically (e.g., genotype 1, genotype 2, etc.). HCV genotype testing is used to determine the required length and potential response to interferon-based therapy.
The Hepatitis C virus (HCV) is a small (50 nm in size), enveloped, single-stranded, positive sense RNA virus in the families Flaviviridae.
The hepatitis C virus (HCV) is transmitted by blood-to-blood contact. In developed countries, it is estimated that 90% of persons with chronic HCV infection were infected through transfusion of unscreened blood or blood products or via injecting drug use. In developing countries, the primary sources of HCV infection are unsterilized injection equipment and infusion of inadequately screened blood and blood products.
Although injection drug use and receipt of infected blood/blood products are the most common routes of HCV infection, any practice, activity, or situation that involves blood-to-blood exposure can potentially be a source of HCV infection.
Methods of transmission
Several activities and practices have been identified as potential sources of exposure to the hepatitis C virus. Anyone who may have been exposed to HCV through one or more of these routes should be screened for hepatitis C.
Injection drug use:Those who currently, or have used drug injection as their delivery route for illicit drugs, are at increased risk for getting hepatitis C because they may be sharing needles or other drug paraphernalia (includes cookers, cotton, spoons, water, etc.), which may be contaminated with HCV-infected blood. An estimated 60% to 80% of all IV drug users in the United States have been infected with HCV. HCV is also transmitted by inhalational drugs, such as intranasal cocaine usage. Harm reduction strategies are encouraged in many countries to reduce the spread of hepatitis C, through education, provision of clean needles and syringes, and safer injecting techniques.
Insuffulated drug use (Drugs which are "snorted") Researchers have suggested that the transmission of HCV may be possible through the insuffulation of illegal drugs such as cocaine and crank when straws ( containing even trace elements of mucous and blood) are shared among users.
Blood products: Blood transfusion, blood products, or organ transplantation prior to implementation of HCV screening (in the U.S., this would refer to procedures prior to 1992) is a decreasing risk factor for hepatitis C.
The virus was first isolated in 1989 and reliable tests to screen for the virus were not available until 1992. Therefore, those who received blood or blood products prior to the implementation of screening the blood supply for HCV may have been exposed to the virus. Blood products include clotting factors (taken by hemophiliacs), immuneglobulin, Rhogam, platelets, and plasma. As of 2001, the Centers for Disease Control and Prevention reports that the risk of HCV infection from a unit of transfused blood in the United States is less than one per million transfused units.
Iatrogenic medical or dental exposure:People can be exposed to HCV via inadequately or improperly sterilized medical or dental equipment. Examples include equipment that may harbor contaminated blood if improperly sterilized include reused needles or syringes, hemodialysis equipment, oral hygiene instruments, and jet air guns, etc. Scrupulous use of appropriate sterilization techniques and proper disposal of used equipment can bring the risk of iatrogenic exposure to HCV to virtually zero.
Occupational exposure to blood Medical and dental personnel, first responders (e.g., firefighters, paramedics, emergency medical technicians, law enforcement officers), and military combat personnel can be exposed to HCV through accidental exposure to blood through accidental needlesticks or blood spatter to the eyes. Universal precautions to protect against such accidental exposures significantly reduce the risk of exposure to HCV.
Recreational exposure to blood: Contact sports and other activities, such as "slam dancing" that may result in accidental blood-to-blood exposure are potential sources of exposure to HCV.
Sexual exposure to blood: Although HCV is not a sexually transmitted disease (STD), transmission can occur during unprotected sexual contact if the sexual activity involves blood-to-blood contact. The sexual spread of HCV is due to blood-blood contact rather than the presence of the virus in vaginal fluid or semen.
Body piercings and tattoos. Tattooing dyes, ink pots, stylets and piercing implements can transmit HCV-infected blood from one person to another if proper sterilization techniques are not followed. Tattoos or piercings performed before the mid 1980's, "underground," or non-professionally are of particularly concern since sterile techniques in such settings may have been or be insufficient to prevent disease.
Shared personal care items
Personal care items such as razors, toothbrushes, cuticle scissors, and other manicuring or pedicuring equipment can easily be contaminated with blood. Sharing such items can potentially lead to exposure to HCV.
HCV is not spread through casual contact such as hugging, kissing, or sharing eating or cooking utensils.
Vertical transmission refers to the transmission of a communicable disease from an infected mother to her child during the birth process. Mother-to-child transmission of hepatitis C has been well described, but occurs relatively infrequently. Transmission occurs only among women who are HCV RNA positive at the time of delivery; the risk of transmission in this setting is approximately 6 out of 100. Among women who are both HCV and HIV positive at the time of delivery, the risk of HCV is increased to approximately 25 out of 100.
Hepatitis C infects an estimated 170 million people worldwide and 4 million in the United States. There are about 35,000 to 185,000 new cases a year in the United States. Co-infection with HIV is common and rates among HIV positive populations are higher. 10,000-20,000 deaths a year in the United States are from HCV; expectations are that this mortality rate will increase, as those who were infected by transfusion before HCV testing become apparent. A survey conducted in California showed prevalence of up to 34% among prison inmates; 82% of subjects diagnosed with hepatitis C have previously been in jail, and transmission while in prison is well described.
Egypt has the highest seroprevalence for HCV, up to 20% in some areas. There is a hypothesis that the high prevalence was linked, in 2000, to a mass-treatment campaign for schistosomiasis, which is endemic in that country.
Co-infection with HIV
Approximately 350,000, or 35% of patients in the USA infected with HIV are also infected with the hepatitis C virus, mainly because both viruses are blood-borne and present in similar populations. In other countries, co-infection is less common, this is possibly related to differing drug policies. HCV is the leading cause of chronic liver disease in the USA. It has been demonstrated in clinical studies that HIV infection causes a more rapid progression of chronic hepatitis C to cirrhosis and liver failure. This is not to say treatment is not an option for those living with co-infection.
Treatment and prognosis
There is a very small chance of clearing the virus spontaneously (0.5 to 0.74% per year), and the majority of patients with chronic hepatitis C will not clear it without treatment.
Current treatment is a combination of pegylated interferon alpha (brand names Pegasys and PEG-Intron) and the antiviral drug ribavirin for a period of 24 or 48 weeks, depending on genotype. Indications for treatment include patients with proven hepatitis C virus infection and persistent abnormal liver function tests. Sustained cure rates (sustained viral response) of 75% or better occur in people with genotypes HCV 2 and 3 in 24 weeks of treatment, about 50% in those with genotype 1 with 48 weeks of treatment and 65% for those with genotype 4 in 48 weeks of treatment. About 80% of hepatitis C patients in the United States have genotype 1. Genotype 4 is more common in the Middle East and Africa. Should treatment with pegylated ribivirin-interferon not return a 2-log viral reduction or complete clearance of RNA (termed early virological response) after 12 weeks for genotype 1, the chance of treatment success is less than 1%. Early virological response is typically not tested for in non-genotype 1 patients, as the chances of attaining it are greater than 90%.
Treatment during the acute infection phase has much higher success rates (greater than 90%) with a shorter duration of treatment (but balance this against the 80% chance of spontaneous clearance without treatment).
Those with low initial viral loads respond much better to treatment than those with higher viral loads (greater than 2 million virons/ml). Current combination therapy is usually supervised by physicians in the fields of gastroenterology, hepatology or infectious disease.
The treatment may be physically demanding, particularly those with a prior history of drug or alcohol abuse. It can qualify for temporary disability in some cases. A substantial proportion of patients will experience a panoply of side effects ranging from a 'flu-like' syndrome (the most common, experienced for a few days after the weekly injection of interferon) to severe adverse events including anemia, cardiovascular events and psychiatric problems such as suicide or suicidal ideation. The latter are exacerbated by the general physiological stress experienced by the patient.
In addition to the standard treatment with interferon and ribavirin, several studies have shown higher success rates when the antiviral drug amantadine (Symmetrel) is added to the regimen. Sometimes called "triple therapy", it involves the addition of 100mg of amantadine twice a day. Studies indicate that this may be especially helpful for "nonresponders" - patients who have not been successful in previous treatments using interferon and ribavirin only. Currently, amantadine is not approved for treatment of Hepatitis C, and studies are ongoing to determine when it is most likely to benefit the patient.
Current guidelines strongly recommend that hepatitis C patients be vaccinated for hepatitis A and B if they have not yet been exposed to these viruses, as this would radically worsen their liver disease.