          
Typically, hepatitis B and hepatitis C infections have distinct phases. The first, or acute phase, occurs soon after infection with the hepatitis virus and lasts for 6 months or less. Many individuals recover from acute hepatitis, and their livers return to normal within a few months. Depending on the type of hepatitis, however, some of the individuals who contract acute hepatitis infections may not be able to eliminate the virus. For these individuals, the acute infection may be followed by a chronic phase. Usually, chronic hepatitis involves a prolonged latent or inactive period. During this time, which may last 20 years or longer, individuals with hepatitis probably do not experience symptoms or feel ill. Generally, however, the virus continues to multiply, gradually causing liver damage. Typically, symptoms do not become apparent until liver damage is extensive. However, abnormal levels of liver enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) may show if liver tests are done. Hepatitis BWhat is it?Hepatitis B is a specific type of hepatitis caused by the virus that has been designated as hepatitis B virus (abbreviated as HBV), which causes inflammation and damage to the liver. As the infection increases, inflammation and destruction of liver cells can interfere with the functions of the liver. Most individuals are able to fight off (or clear) infection with HBV
and they recover in 2 to 4 months. Ordinarily individuals only get
hepatitis B once and after the HBV infection has been cleared, the
individual is usually left with lifelong immunity . Up to 10% of adults,
50% of children under the age of 5, and 90% of infants who contract
hepatitis B will not be able to eliminate the virus in 6 months. These
individuals are considered to be chronic carriers of HBV. It is estimated that chronic hepatitis B affects 1.25 million people
in the United States and leads to 5,000 U.S. deaths per year. Chronic
hepatitis puts individuals at a greater risk of developing cirrhosis or
liver cancer. Cirrhosis is a condition that gradually replaces active
liver cells with inactive scar tissue. Slowly, liver function is lost
and liver failure may result. However, individuals who are chronic
carriers of HBV but who have no symptoms are much less likely to develop
cirrhosis than individuals who have chronic symptoms of hepatitis B. What causes it?HBV is transmitted from individual to individual through contact with infected bodily fluids, such as blood. Because chronic carriers of HBV are often unaware that they have the virus, they may transmit the disease to others unknowingly. Injecting illegal drugs with contaminated needles or having sex with an infected individual are common ways to become infected. Sharing and reusing diabetes blood testing supplies with any infected individual may also cause an individual to become infected. In addition, instruments such as those used for tattooing and body piercing can spread hepatitis if they are not properly sterilized between uses. A mother who is infected can transmit HBV to her baby during childbirth. However, it is not transmitted through breast-feeding. Once HBV makes its way to the liver, it multiplies. Symptoms usually develop within one to 6 months. Exactly how liver cells are damaged or why some individuals acquire chronic infection or liver cancer is unknown. Who has it?Of all the serious transmittable diseases, hepatitis is the most common. The Centers for Disease Control and Prevention (CDC) received about 73,000 reports of new cases in 2003, and the CDC estimates that 1.25 million Americans are infected with chronic hepatitis B. Hepatitis B affects individuals of both sexes and all ages, ethnic groups, and sexual orientations. About one-fifth of the world’s population will have hepatitis B at sometimes in their lives. It is more common in males, with the highest occurrence between the ages of 20 and 49 years. Individuals with hemophilia may be slightly more at risk, if they use clotting factors that are made from human blood. In the United States, the acute form of hepatitis has been declining due to the availability of an effective vaccine and the aggressive promotion of vaccination among children and teenagers. Changes in high-risk behavior may also contribute to the decrease. In 1990, approximately 21,000 Americans were believed to have acute hepatitis B. By 2002, that number had dropped to approximately 8,000. Chronic hepatitis B affects an estimated 1.25 million Americans and about 300 million chronic carriers are believed to exist in the world population. As the number of acute cases goes down, the number of chronic carriers of hepatitis B is also expected to decline. However, increases in occurrence have been observed among the major risk groups: individuals with compromised immune systems, sexually active individuals, and injectable drug users. What are the risk factors?Risk factors are circumstances or conditions that can increase the chances of developing a condition. Some of these behaviors can be changed and taking special precautions may be helpful for limiting others. Risk factors for hepatitis B include: • Being tattooed or having body or ear piercing with contaminated
instruments Other individuals who may be at greater risk are: • Dialysis patients What are the symptoms?Many individuals who contract HBV are not even aware that they have hepatitis because the symptoms may be so mild. The most common symptoms of hepatitis B are often mistaken for the flu and they may not be recognized because they may not appear until one to 6 months after becoming infected. Some of these symptoms may be: • Fatigue Additional symptoms that may appear a few days after the initial symptoms include: • Bitter taste in the mouth or bad breath The following symptoms of more serious liver damage may occur months to years later in individuals with chronic hepatitis B: • Bruising easily or the appearance of “spider veins” broken blood
vessels that form a tangled, spiderlike appearance under the skin How is it treated?Hepatitis B that lasts beyond 6 months or becomes serious may be treated with several different medications, but not every case needs to be treated. Whether on not an individual with hepatitis B is taking medication, regular visits to a doctor who specializes in liver diseases are very important. Laboratory tests that measure liver function, need to be performed regularly to track disease progression and to determine possible complications. Because no cure has been found for hepatitis B, treatment is aimed at decreasing the ability of the virus to multiply, decreasing inflammation and damage to the liver, and increasing the immune system’s ability to fight the virus. Currently, drug treatments seem to be most helpful for individuals who have liver disease caused by hepatitis B. Unfortunately, there is no drug treatment for the acute phase of hepatitis B. Nausea and vomiting often seen with early infection is treated with fluid replacement. In the United States, the four drugs that have been approved by the Food and Drug Administration (FDA) for treating chronic hepatitis B are: PEGASYS AND RIBAVIRIN
Prevention of hepatitis BHepatitis B cannot be cured, but it can be prevented relatively easily. Before exposure to HBVThe hepatitis B vaccine (Engerix-B, Recombivax HB) is a safe and effective protection from hepatitis B. Given as three injections during a 6-month period, it generally produces immunity for 15 years or longer. Generally, the injections are given in a doctor’s office or clinic. Currently, hepatitis B vaccination is required by many school districts before a student is admitted. It is recommended for all individuals under the age of 19 years and for individuals who:
After exposure to the virusIndividuals who know or believe that they have been exposed to HBV, including babies born to mothers who test positive for HBV, should receive the three hepatitis B vaccine injections. They should also get one injection of hepatitis B immune globulin (BayHep B, Nabi-HB). Abbreviated as HBIG, this medication is made up of immune system proteins that specifically help to fight HBV. What is on the horizon?Many antiviral and immune system-stimulating drugs are being investigated.
In other research, blood and urine tests for early detection of the
liver complications that may be associated with hepatitis B, are very
close to being approved. Researchers have already been able to isolate
proteins and markers of liver cancer and liver disease in individuals
affected by hepatitis B. HEPATITS CWhat is it?Hepatitis C is a specific type of hepatitis caused by the virus that has been designated as hepatitis C virus (abbreviated as HCV). Formerly known as non-A, non-B hepatitis, hepatitis C is different from other hepatitis viruses because it changes (mutates) constantly and unpredictably. Mutation not only makes HCV difficult for individuals to fight, it also makes finding a treatment or a vaccination extremely difficult. A diagnosis of acute hepatitis C is rare because its symptoms, which typically are very mild, may not be present at all during the acute phase of infection. According to the Centers for Disease Control and Prevention (CDC), up to 80% of individuals who are infected with acute HCV do not even know they have it. If symptoms are noticed, they are frequently mistaken for a case of flu. Whether or not they are noticed, symptoms of acute hepatitis C infection usually begin approximately 7 to 10 weeks after infection with HCV, although they can take as little as 2 weeks or as long as 20 weeks to develop. Known as the incubation period, the time from infection with HCV to the onset of symptoms is the time that the virus multiplies and attacks the liver. As a result, the liver becomes inflamed, tender, and swollen. Acute hepatitis C is generally considered to last for 6 months or less. About 75% to 85% of individuals who have acute hepatitis C will progress to the chronic or long-lasting phase. Defined as hepatitis C that lasts longer than 6 months, chronic hepatitis C can take 20 years or longer to develop into cirrhosis, liver failure, or liver cancer. Often caused by long-term alcoholism, cirrhosis occurs when normal liver cells are replaced by non-functioning scar tissue and fibers. Gradually, the liver loses the ability to break down toxins in the blood, regulate blood clotting, and produce essential substances such as bile. What causes it?Why HCV attacks liver cells is not well understood, but liver damage may be caused in at least three possible ways:
Who has it?Estimates of the number of individuals in the world who have hepatitis C range from about 150 million to about 200 million. Although it affects members of all ethnic groups, hepatitis C appears to be more common in less industrialized areas of the world, with estimates as high as 10% to 15% of the population in some countries. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), nearly 4 million Americans (about 2% of the population) show evidence of having had an infection with HCV. Only about 25% of those individuals experienced symptoms that were attributed to hepatitis C, but 75% to 85% of them went on to the chronic phase. Most will develop chronic liver disease, which may progress to cirrhosis or liver cancer. In the 1970s and 1980s, a number of individuals got hepatitis C from donated blood that was contaminated with HCV, Today, the risk of transfusion-associated hepatitis C is very low (approximately one chance for every 100,000 units that are transfused). What are the risk factors?Mainly, HCV is passed from one individual to another through blood and blood products. A much smaller chance exists that it may also be transferred in bodily secretions, such as semen. The risk for infection with HCV is increased for individuals who:
Symptoms of acute hepatitis C are usually described as mild and flu-like. Chronic-stage symptoms develop slowly as the virus damages the liver.
As a result of the continuing damage, several complications can develop from chronic hepatitis C. Possible Complications of Hepatitis C Infection
Once chronic hepatitis C is diagnosed, laboratory tests may be performed several times a year to assess liver function and general health. By measuring the levels of specific liver enzymes and other substances in the blood, doctors can determine the approximate extent of damage as well as what complications may be developing. Liver tests may include:
In addition, the results of general blood tests may be affected by loss of liver function. Among these substances are:
How is it treated?Currently, hepatitis C infection has no cure. Benefits of treatment in acute hepatitis C infection are questionable at this time, because hepatitis C is rarely diagnosed during the acute phase of the infection. The ideal time to start drug therapy also remains unknown; however, recent evidence suggests that starting interferon early may be highly effective. Each individual’s doctor must determine the most appropriate therapy. In 2001, great progress was made in the treatment of chronic hepatitis C. First, the FDA approved peginterferon, a specially adapted form of artificial interferon that resists breakdown by the immune system. Interferons are antiviral proteins produced by the immune system. Synthetically-manufactured interferons are used to treat a number of conditions. Peginterferon offers several advantages, including increased effectiveness and less frequent dosing, over standard synthetic interferons. Also in 2001, ribavirin, an oral antiviral medication, was approved as a single agent. It was formerly available only in combination with interferon. Currently, combination treatment with peginterferon alfa (injected once weekly) and ribavirin (taken orally on a daily schedule) is the preferred treatment for adult hepatitis C patients who have never been on interferon therapy before. The most common reason for liver transplantation in the United States is liver failure due to chronic infection with HCV. Liver transplants become necessary for approximately 15% of individuals with chronic hepatitis C. Unfortunately, as many as 90% of the hepatitis C patients who undergo liver transplantation will be re-infected with HCV, since no absolute cure exists. What is on the horizon?Several new treatment options are under investigation for hepatitis C. Among them are: Triple TherapyUnfortunately, because HCV mutates relatively quickly, it develops forms that resist medications. Therefore, currently-recommended therapies eventually lose effectiveness for many individuals with hepatitis C. HCV To limit viral resistance, triple therapy is currently being researched. This approach adds amantadine, an antiviral agent currently approved for use against the influenza A virus, to therapy with interferon and ribavirin. Preliminary results from individuals using the triple therapy showed more normal liver tests and long-term clearing of HCV from the blood. Inosine Monophosphate Dehydrogenase (IMPDH) InhibitorA new class of drugs called inosine monophosphate dehydrogenase (IMPDH) inhibitors is believed to work by interfering with an enzyme used by HCV to multiply. One member of this class, currently known as merimepodib or VX-497, is being investigated for the treatment of hepatitis C in individuals that do not respond to combination therapy with interferon and ribavirin. Although they also need to be used with interferon, IMPDH inhibitors appear to work in ways that are similar to the ways that ribavirin helps to normalize liver tests. Hammerhead RibozymesRibozymes are proteins capable of breaking down the genetic material of viruses. A new treatment strategy is studying “hammerhead” (named because their chemical structure is shaped like a hammer’s head) ribozymes to prevent HCV replication. Therefore, the chance that the body can eliminate HCV increases. Preliminary results from treatment with hammerhead ribozymes are promising, with one study showing that some of them may inhibit virus duplication by as much as 95%. Combining a ribozyme with interferon possibly could increase inhibition of the virus to 99% or more. AlkovirsAlkovirs are another new class of drug currently being tested for the treatment of both HCV and hepatitis B virus (HBV). Because alkovirs, which are taken orally, may activate the body’s own immune system, they may act like interferons. As a result of treatment with alkovirs, the body may be able to eliminate HCV before liver damage becomes severe. Other Experimental TherapiesSeveral potentially useful therapies are still in very early stages of experimental stages. They include:
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