|
Search over 100 encyclopedias and dictionaries: |
Research categories | Follow us on Twitter |
Research categories
View all topics in the newsView all reference sources at Encyclopedia.com |
|||
Hepatitis B Vaccine
Hepatitis B vaccineDefinitionThe hepatitis B vaccine (HBV or HepB) is an injection that protects children from contracting hepatitis B, a serious disease caused by the hepatitis B virus. DescriptionThe hepatitis B vaccine consists of a small protein from the surface of the hepatitis B virus called the hepatitis B surface antigen (HBsAg). After vaccination with HBV, the child's immune system recognizes HBsAg as foreign and produces antibodies that attach to the protein (anti-HBs). These specific antibodies remain in the blood. Later, if the child becomes infected with the hepatitis B virus, the antibodies recognize the protein and stimulate the immune system to produce large quantities of specific antibodies that attach to and destroy the virus and prevent the disease. HBV is usually the first vaccine a child receives, most often before leaving the hospital after birth. The second and third HBV immunizations are administered by the age of 18 months, in conjunction with other routine childhood vaccinations. Vaccine formulationsThe HBsAg in HBVs is referred to as recombinant because it is genetically engineered. The gene encoding the DNA for HBsAg is introduced into common baker's yeast. The yeast is grown in vats in which large amounts of HBsAg are produced. The yeast cells are broken, and the HBsAg is isolated and purified. It is adsorbed into aluminum hydroxide. Packaged hepatitis B vaccine contains the following:
Two HBVs are approved for use in the United States. Recombivax HB, manufactured by Merck & Company, is as of 2004 available as a pediatric/adolescent formulation (orange cap) and as an adult formulation (green cap). Engerix-B, made by SmithKline Beecham Biologicals, is as of 2004 available as a pediatric formulation (blue cap) and as an adult formulation (orange cap). In general these HBVs are interchangeable and either or both can be used in an individual immunization series. An HBV derived from the blood serum of people with hepatitis B was as of 2004 no longer produced in the United States. DosagesThe immune response to HBV varies among individual children. Therefore, the HBV dose should be determined by a medical professional. In general, the recommended doses are as follows:
SafetyAlthough the vast majority of parents believe that vaccinations are important for their children, the majority of parents are also concerned about the safety of vaccines including HBV. Although controversy over the safety of HBV resulted in congressional hearings in 1999, the National Academy of Science's Institute of Medicine, as well as other authorities, considers HBV to be safe. Repeated studies have found no association between HBV and sudden infant death syndrome (SIDS) or other medical conditions, including neurological or immune system disorders. EffectivenessHBV usually is effective in protecting against hepatitis B. (HBV also protects against the related hepatitis D virus, which occurs as a co-infection with hepatitis B and usually results in more severe disease symptoms.) However, the immune response to HBV varies among children, apparently due to genetic variations in individual immune systems. In addition, the following medical conditions may cause children to benefit less from HBV:
The duration of hepatitis B immunity following infant vaccination is not known. A 2004 study found that most low-risk children vaccinated at birth did not have antibodies against hepatitis B in their blood by the time they reached the age of five. Although the majority of these children responded positively to a booster HBV immunization, one-third of them did not respond. Likewise, a 2003 Israeli study found a steady decline in anti-hepatitis-B antibodies over time in children vaccinated as infants. The steepest decline in the antibodies occurred between five and eight years after vaccination. General use Hepatitis B in childrenThe U.S. Centers for Disease Control and Prevention (CDC) estimates that, prior to the launch of the infant HBV immunization program, about 33,000 American children of non-infected mothers acquired hepatitis B by the age of ten. Hepatitis B is a potentially serious disease caused by the hepatitis B virus. It may result in inflammation and damage to the liver. Hepatitis B infection may be without symptoms or with acute or short-lived symptoms that can include:
The hepatitis B virus is eventually cleared from the bodies of most infected adolescents and adults. Only about 2–6 percent of infected older children and adults develop chronic hepatitis B and can continue to transmit the virus to other people. By contrast 90 percent of infants and 30 percent of young children infected with hepatitis B develop chronic disease: the younger the child, the more likely that a hepatitis B infection will become chronic. The consequences of chronic hepatitis B infection may include:
There is no cure for hepatitis B and approximately one-fourth of chronic hepatitis B victims die of cirrhosis or liver cancer, including children who do not survive to young adulthood. Of the approximately 1.25 million Americans with chronic hepatitis B, 20–30 percent were infected as infants or children. Risk of childhood infectionThose with the highest risk for infection are older adolescents and adults engaging in high-risk behaviors such as drug use and unprotected sex with multiple partners. Far less common sources of childhood hepatitis B infection include:
However, the following children are at particular risk for hepatitis B infection:
Children born to infected mothersChildren of hepatitis B-infected mothers are at a 10–85 percent risk of becoming infected during birth. The CDC estimates that, prior to the infant HBV immunization program, about 12,000 American infants per year were infected by their mothers at birth. In addition, children of hepatitis B-infected mothers are at high risk of becoming infected before the age of five. Children under the age of five who become infected with hepatitis B are at high risk for chronic infection and severe liver damage and disease later in life, even though initially they may have no symptoms. These infected children have a 90 percent risk of chronic hepatitis B infection and as many as 25 percent of them will die of chronic liver disease as adults. Mothers who have emigrated from countries with high rates of endemic hepatitis B are more likely to be infected. Mothers with acute or chronic infectious hepatitis B can be identified by a blood test for HBsAg. Children born to mothers who have hepatitis B or whose hepatitis B status is unknown should receive their first HBV dose within 12 hours of birth. The second and third doses are given at two and six months of age. In many parts of the world, vaccine intervention before birth is required to prevent hepatitis B infection and its consequences in newborns. It is recommended that newborns whose mothers are HBsAg-positive receive hepatitis B immune globulin (HBIG)—a preparation of serum containing high levels of antibodies to hepatitis B—as well as HBV within 12 hours of birth. About 70 percent of these newborns will be protected from chronic hepatitis B. A child's immune response to either hepatitis B infection or to HBV can be measured by a blood test for antibodies to HBsAg (anti-HBs). If a vaccinated child is exposed to hepatitis B, a measure of the anti-HBs in the blood will indicate whether another dose of HBV is required. Infants born to mothers who are HBsAg-positive should be tested for anti-HBs three to nine months following their last dose of vaccine. Their anti-HB levels should be at least 10 milli-international units per milliliter (mIU/ml), indicating that they are immune due to vaccination. Mass immunizationHBV first became available in the United States in 1982. Between 1979 and 1989, the incidence of acute hepatitis B increased in the United States by 37 percent. There were 200,000–300,000 new infections annually between 1980 and 1991. In 1991 the CDC developed a strategy for eliminating the transmission of hepatitis B via universal childhood vaccination. The World Health Organization also declared the goal of immunizing all infants worldwide. Nearly all states enacted laws requiring hepatitis B vaccination for enrollment in daycare, schools, and colleges. All these laws include exemptions for medical reasons and most include exemptions for religious reasons; however, only a few states allow exemptions from vaccination on philosophical grounds. Most states do not have laws mandating the screening of pregnant women for HBsAg. By 2002, 90 percent of American children had been vaccinated against hepatitis B. The number of children carrying the virus was subsequently reduced substantially. Infant death from hepatitis B and the incidence of liver disease in children also decreased significantly. The CDC estimates that in 1998 the vaccine prevented 6,800 infections during birth and 18,700 infections in infants and children up to the age of nine. About 12,900 of these children would have developed chronic hepatitis and 3,000 of them eventually would have died of cirrhosis or liver cancer. The CDC expects the overall incidence of hepatitis B in the American population to fall throughout the early 2000s as a result of mass childhood vaccination. However, as of 2004, infants receiving HBV since 1991 had not yet reached the age when high-risk behaviors increase the likelihood of hepatitis B infection. In Pacific Island nations—where rates of hepatitis B infection are among the highest in the world—a regionally coordinated immunization program has significantly reduced the incidence of chronic infection. CostsHBV usually is covered by health insurance. In the United States the Vaccines for Children program covers the cost of hepatitis B vaccination for those without health insurance and for other specific groups of children, including Native Americans. The CDC estimates that infant hepatitis B vaccination saves fifty cents in direct medical costs for every dollar spent on HBV. PrecautionsBecause most children are not at high risk for hepatitis B infection, and because the duration of immunity provided by HBV is not known, some parents and medical professionals question the need for and the effectiveness of childhood vaccination against hepatitis B. Some also continue to question the safety of the vaccine. Children should not receive HBV if they are allergic to baker's yeast or thimerosal, are allergic to any other components in a combination vaccine, or have had a previous allergic reaction to HBV. A 2003 study found that HBV was safe and effective in children with asthma , even those on inhaled steroid therapy. Side effectsAlthough most children experience no side effects from HBV, the most common side effects are as follows:
Other less common side effects of HBV include:
Other rare reactions to HBV include:
Although allergic reactions to HBV are rare, if they occur emergency medical help should be sought immediately. Symptoms of an allergic reaction include:
Parental concernsPreparing a child for an injectionMost children are afraid of injections; however, there are simple methods for easing a child's fear . Prior to the vaccination parents should take the following steps:
During the vaccination parents should take the following steps:
Comforting restraintParents may choose to use a comforting restraint method while their child is receiving an injection. These methods enable the parent to control and steady the child's arm while not holding the child down. With infants and toddlers, the following holds may be effective:
With older children, the following positions may be effective:
After the injectionFollowing an injection parents should help in the following ways:
KEY TERMSAntibody —A special protein made by the body's immune system as a defense against foreign material (bacteria, viruses, etc.) that enters the body. It is uniquely designed to attack and neutralize the specific antigen that triggered the immune response. Antigen —A substance (usually a protein) identified as foreign by the body's immune system, triggering the release of antibodies as part of the body's immune response. Booster immunization —An additional dose of a vaccine to maintain immunity to the disease. Cirrhosis —A chronic degenerative disease of the liver, in which normal cells are replaced by fibrous tissue and normal liver function is disrupted. The most common symptoms are mild jaundice, fluid collection in the tissues, mental confusion, and vomiting of blood. Cirrhosis is associated with portal hypertension and is a major risk factor for the later development of liver cancer. If left untreated, cirrhosis leads to liver failure. Comvax —Hib-HepB, a combination vaccine that protects against the Haemophilus influenzae type B bacterium and the hepatitis B virus. Haemophilus influenzae type B —An anaerobic bacteria associated with human respiratory infections, conjunctivitis, and meningitis. Hepatitis B immune globulin —HBIG, a blood serum preparation containing anti-hepatitis-B antibodies (anti-HBs) that is administered along with HBV to children born to hepatitis-B-infected mothers. Immunity —Ability to resist the effects of agents, such as bacteria and viruses, that cause disease. ResourcesBOOKSAtkinson, William, and Charles (Skip) Wolfe, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases, 7th ed. Atlanta, GA: National Immunization Program, Centers for Disease Control and Prevention, 2003. Blumberg, Baruch S. Hepatitis B: The Hunt for a Killer Virus. Princeton, NJ: Princeton University Press 2003. Converse, Judy. When Your Doctor Is Wrong: Hepatitis B and Autism. Philadelphia, PA: Xlibris Corp., 2002. Hepatitis B Vaccine: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, CA: Icon Group International, 2004. PERIODICALSPetersen, K. M., et al. "Duration of Hepatitis B Immunity in Low Risk Children Receiving Hepatitis B Vaccinations from Birth." The Pediatric Infectious Disease Journal 23 (July 2004): 650–5. Shouval, D. "Hepatitis B Vaccines." Journal of Hepatology 39 Suppl. 1 (2003): S70–6. ORGANIZATIONSImmunization Action Coalition. 1573 Selby Ave., St. Paul, MN 55104. Web site: <www.immunize.org>. National Immunization Program. NIP Public Inquiries, Mailstop E-05, 1600 Clifton Rd. NE, Atlanta, GA 30333. Web site: <www.cdc.gov/nip>. National Vaccine Information Center. 421-E Church St., Vienna, VA 22180. Web site: <www.909shot.com> WEB SITES"Hepatitis B Facts: Testing and Vaccination." Immunization Action Coalition. Available online at <www.immunize.org/catg.d/p2110.htm> (accessed December 22, 2004). Margaret Alic, Ph.D. |
|
|
Cite this article
Alic, Margaret. "Hepatitis B Vaccine." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. Alic, Margaret. "Hepatitis B Vaccine." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1G2-3447200274.html Alic, Margaret. "Hepatitis B Vaccine." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3447200274.html |
|
Hepatitis B
Hepatitis BDefinitionHepatitis B is a liver disease caused by the hepatitis B virus (HBV). DescriptionHepatitis B is a form of viral hepatitis that is also known as serum hepatitis, due to its ability to be spread through body fluids and blood. HBV can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer , liver failure, and death. Hepatitis B is a more severe liver disease than hepatitis A , and asymptomatic infections occur frequently. Chronic hepatitis B infection may take one of two forms: chronic persistent hepatitis, a condition characterized by persistence of the virus but in which liver damage is minimal; and chronic active hepatitis, in which there is aggressive destruction of liver tissue and rapid progression to cirrhosis or liver failure. TransmissionTransmission of HBV occurs through blood and body fluid exposure such as blood, semen, vaginal secretions, or saliva. Hepatitis B is not spread through food or water or by casual contact. Infants may also develop the disease if they are born to a mother who has the virus. Infected children often spread the virus to other children if there is frequent contact or a child has many scrapes or cuts. The common modes of transmission of hepatitis B are as follows:
DemographicsWorldwide there are 450 million carriers of hepatitis B, 50 million of which are in Africa. Carriage rates vary markedly in different areas. In South Africa, infection is much more common in rural communities than in the cities. According to the Centers for Disease Control (CDC), an estimated 78,000 persons in the United States were infected with HBV in 2001. People of all ages get hepatitis B, and about 5,000 die per year of sickness caused by HBV. An estimated 1.25 million Americans are chronically infected, of whom 20 to 30 percent acquired their infection in childhood. It is estimated that hepatitis B accounts for 20 to 25 percent of all acute viral hepatitis in children. Infected newborns rarely suffer but have 90 percent chance of becoming carriers. Twenty-five percent of all HAV positive newborns develop chronic liver disease by the third to fourth decade of life. Causes and symptomsHepatitis B is caused by HBV, also called Hepadna virus. The virus has an incubation period of two to five months. It replicates in the liver, and virus particles are shed in large amounts into the blood. The blood of infected individuals is thus highly infectious. Hepatitis B has a wide range of symptoms. It can also be mild, without symptoms. When present, the symptoms are non-specific and usually include fever , tiredness, loss of appetite, nausea , abdominal discomfort, dark urine, clay-colored bowel movements, and jaundice (yellowing of the skin and eyes). When to call the doctorParents should call the doctor immediately if any of the following occurs:
DiagnosisA blood test is required to diagnose hepatitis B. The test detects one of the viral antigens called hepatitis B surface antigen (HBsAg) in the blood. Later on, HBsAg may no longer be present, in which case a test for antibodies to a different antigen, called hepatitis B core antigen, is used. If HBsAg can be detected in the blood for longer than six months, chronic hepatitis B is diagnosed. TreatmentThere is no cure for hepatitis B and no specific treatment is available. However, the following guidelines are often recommended:
Nutritional concernsParents should ensure that their infected child has a well-balanced diet. Children with advanced liver disease need to follow specific diets issued by the treating physician. However, most children are not in this category, and no special diet is recommended for them, except that they should avoid eating fatty foods because the body has difficulty digesting fat when the liver is not working well. However, adequate protein intake is important to regenerate liver cells. Children without liver cirrhosis require about 1–2 grams of protein per pound (2–3 grams per kilogram) of body weight. Children with cirrhosis need an individual nutrition plan from their pediatric specialist or nutritionist. There is some evidence that iron can lower the response to interferon treatment in adults. Although no results have been reported for children, the issue of restricting iron intake should be discussed with the treating physician. PrognosisViral hepatitis symptoms usually last three weeks to two months but may last up to six months. Children may return to daycare one week after symptoms first appear, with the doctor's permission. Most children with hepatitis get better naturally without liver problems later on in life. However, some children do have subsequent liver problems. Thus, it is important to keep in close touch with the treating physician and to keep all follow-up appointments. Chronic, or relapsing, infection occurs with hepatitis B in about 5–10 percent of cases. PreventionA vaccine for hepatitis B is as of 2004 widely used in the United States for routine childhood immunization. Children usually receive the first vaccine between birth and two months of age, the second vaccine at one to four months, and the third vaccine at six to 18 months. The vaccine is generally required for all children born on or after January 1, 1992, before they enter school. The vaccine is available for older children who may have not been immunized before 1992 and is recommended before age 11 or 12. Parental concernsIf mothers have HBV in their blood, they can give hepatitis B to their baby during childbirth . Babies who get HBV at birth may have the virus for the rest of their lives, can spread the disease, and can get cirrhosis of the liver or liver cancer. The CDC recommends that all pregnant women be tested for HBV early in their pregnancy. If the blood test is positive, the baby should receive vaccine along with hepatitis B immune globulin (HBIG) at birth. The second dose of vaccine should be given at one to two months of age and the third dose at six months of age. KEY TERMSCirrhosis —A chronic degenerative disease of the liver, in which normal cells are replaced by fibrous tissue and normal liver function is disrupted. The most common symptoms are mild jaundice, fluid collection in the tissues, mental confusion, and vomiting of blood. Cirrhosis is associated with portal hypertension and is a major risk factor for the later development of liver cancer. If left untreated, cirrhosis leads to liver failure. Hepatitis B virus (HBV) —Also called Hepadna virus, the pathogen responsible for hepatitis B infection. Jaundice —A condition in which the skin and whites of the eyes take on a yellowish color due to an increase of bilirubin (a compound produced by the liver) in the blood. Also called icterus. Vaccine —A substance prepared from a weakened or killed microorganism which, when injected, helps the body to form antibodies that will prevent infection by the natural microorganism. See also Hepatitis A; Hepatitis B vaccine; Vaccination. ResourcesBOOKSAchord, James. Understanding Hepatitis. Jackson: University of Mississippi Press, 2002. Berkman, Alan, and N. Bakalar. Hepatitis A to G: The Facts You Need to Know about All the Forms of This Dangerous Disease. Clayton, Australia: Warner Books, 2000. Blumberg, Baruch S. Hepatitis B: The Hunt for a Killer Virus. Princeton, NJ: Princeton University Press, 2002. Everson, Gregory T., et al. Living with Hepatitis B: A Survivor's Guide. Long Island City, NY: Hatherleigh Press, 2004. Green, William F., and H. Conjeevaram. The First Year—Hepatitis B: An Essential Guide for the Newly Diagnosed. New York: Marlowe & Co., 2002. PERIODICALSArya, G., and W. F. Balistreri. "Pediatric liver disease in the United States: Epidemiology and impact." Journal of Gastroenterology & Hepatology 17, no. 5 (May 2002): 521–25. Helvaci, M., et al. "Efficacy of hepatitis B vaccination and interferon-[alpha]-2b combination therapy versus interferon-[alpha]-2b monotherapy in children with chronic hepatitis B." Journal of Gastroenterology & Hepatology 19, no. 7 (July 2004): 785–91. Liberek, A., et al. "Tolerance of interferon-alpha therapy in children with chronic hepatitis B." Journal of Paediatrics & Child Health 63, no. 23 (2003): 2625–49. Murdoch, David L. et al. "Combined Hepatitis A and B Vaccines: A Review of Their Immunogenicity and Tolerability." Drugs 40, no. 5–6 (May-June 2004): 265–69. Shulman, Stanford T. "The History of Pediatric Infectious Diseases." Pediatric Research 55, no. 1 (January 2004): 163–176. Sokal, Etienne. "Drug Treatment of Pediatric Chronic Hepatitis B." Pediatric Drugs 4, no. 6 (2002): 361–69. ORGANIZATIONSAmerican Liver Foundation (ALF). 75 Maiden Lane, Suite 603, New York, NY 10038–4810. Web site: <www.liverfoundation.org>. Hepatitis B Foundation. 700 East Butler Avenue, Doylestown, PA 18901–2697. Web site: <www.hepb.org>. Hepatitis Foundation International (HFI). 504 Blick Drive, Silver Spring, MD 20904–2901. Web site: <www.liverfoundation.org>. National Center for Infectious Diseases (NCID). Centers for Disease Control and Prevention, Mailstop C-14, 1600 Clifton Road, Atlanta, GA 30333. Web site: <www.cdc.gov/ncidod>. WEB SITES"Viral Hepatitis B Homepage." NCID. Available online at <www.cdc.gov/ncidod/diseases/hepatitis/b/index.htm> (accessed October 22, 2004). "What I need to know about Hepatitis B Homepage." NIHNDDIC. Available online at <http://digestive.niddk.nih.gov/ddiseases/pubs/hepb_e/> (accessed October 22, 2004). Monique Laberge, Ph.D. |
|
|
Cite this article
Laberge, Monique. "Hepatitis B." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. Laberge, Monique. "Hepatitis B." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1G2-3447200273.html Laberge, Monique. "Hepatitis B." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3447200273.html |
|
Hepatitis B
Hepatitis BDefinitionHepatitis B is a potentially serious form of liver inflammation due to infection by the hepatitis B virus (HBV). It occurs in both rapidly developing (acute) and long-lasting (chronic) forms, and is one of the most common chronic infectious diseases worldwide. An effective vaccine is available that will prevent the disease in those who are later exposed. DescriptionCommonly called "serum hepatitis," hepatitis B ranges from mild to severe. Some people who are infected by HBV develop no symptoms and are totally unaware of the fact, but they may carry HBV in their blood and pass the infection on to others. In its chronic form, HBV infection may destroy the liver through a scarring process, called cirrhosis, or it may lead to cancer of the liver. When a person is infected by HBV, the virus enters the bloodstream and body fluids, and is able to pass through tiny breaks in the skin, mouth, or the male or female genital area. There are several ways of getting the infection:
Although there are many ways of passing on HBV, the virus actually is not very easily transmitted. There is no need to worry that casual contact, such as shaking hands, will expose one to hepatitis B. There is no reason not to share a workplace or even a restroom with an infected person. More than 300 million persons throughout the world are infected by HBV. While most who become chronic carriers of the virus live in Asia and Africa, there are no fewer than 1.5 million carriers in the United States. Because carriers represent a constant threat of transmitting the infection, the risk of hepatitis B is always highest where there are many carriers. Such areas are said to be endemic for hepatitis B. When infants or young children living in an endemic area are infected, their chance of becoming a chronic hepatitis B carrier is at least 90%. This probably is because their bodies are not able to make the substances (antibodies) that destroy the virus. In contrast, no more than 5% of infected teenagers and adults develop chronic infection. Causes and symptomsWith the exception of HBV, all the common viruses that cause hepatitis are known as RNA viruses because they contain ribonucleic acid or RNA as their genetic material. HBV is the only deoxyribonucleic acid or DNA virus that is a major cause of hepatitis. HBV is made up of several fragments, called antigens, that stimulate the body's immune system to produce the antibodies that can neutralize or even destroy the infecting virus. It is, in fact, the immune reaction, not the virus, that seems to cause the liver inflammation. Acute hepatitis BIn the United States, a majority of acute HBV infections occur in teenagers and young adults. Half of these youth never develop symptoms, and only about 20%—or one in five infected patients—develop severe symptoms and yellowing of the skin (jaundice ). Jaundice occurs when the infected liver is unable to get rid of certain colored substances, or pigments, as it normally does. The remaining 30% of patients have only "flu-like" symptoms and will probably not even be diagnosed as having hepatitis unless certain tests are done. The most commom symptoms of acute hepatitis B are loss of appetite, nausea, generally feeling poorly, and pain or tenderness in the right upper part of the abdomen (where the liver is located). Compared to patients with hepatitis A or C, those with HBV infection are less able to continue their usual activities and require more time resting in bed. Occasionally patients with HBV infection will develop joint swelling and pain (arthritis) as well as hives or a skin rash before jaundice appears. The joint symptoms usually last no longer than three to seven days. Typically the symptoms of acute hepatitis B do not persist longer than two or three months. If they continue for four months, the patient has an abnormally long-lasting acute infection. In a small number of patients—probably fewer than 3%—the infection keeps getting worse as the liver cells die off. Jaundice deepens, and patients may bleed easily when the levels of coagulation factors (normally made by the liver) decrease. Large amounts of fluid collect in the abdomen and beneath the skin (edema ). The least common outcome of acute HBV infection, seen in fewer than 1% of patients, is fulminant hepatitis, when the liver fails entirely. Only about half of these patients can be expected to live. Chronic hepatitis BHBV infection lasting longer than six months is said to be chronic. After this time it is much less likely for the infection to disappear. Not all carriers of the virus develop chronic liver disease; in fact, a majority have no symptoms. But, about one in every four HBV carriers develop liver disease that gets worse over time, as the liver becomes more and more scarred and less able to carry out its normal functions. A badly scarred liver is called cirrhosis. Patients are likely to have an enlarged liver and spleen, as well as tiny clusters of abnormal blood vessels in the skin that resemble spiders. The most serious complication of chronic HBV infection is liver cancer. Worldwide this is the most common cancer to occur in men. Nevertheless, the overall chance that liver cancer will develop at any time in a patient's life is probably much lower than 10%. Patients with chronic hepatitis B who drink or smoke are more likely to develop liver cancer. It is not unusual for a person to simultaneously have both HBV infection and infection by HIV (human immunodeficiency virus, the cause of AIDS ). A study released in 2003 reported that men infected with both HIV and HBV were more likely to die from liver disease than people infected with just one of the diseases. DiagnosisHepatitis B is diagnosed by detecting one of the viral antigens—called hepatitis B surface antigen (HBsAg)—in the blood. Later in the acute disease, HBsAg may no longer be present, in which case a test for antibodies to a different antigen—hepatitis B core antigen—is used. If HBsAg can be detected in the blood for longer than six months, chronic hepatitis B is diagnosed. A number of tests can be done to learn how well, or poorly, the liver is working. They include blood clotting tests and tests for enzymes that are found in abnormally high amounts when any form of hepatitis is present. TreatmentIn the past, there was no treatment available for hepatitis B. But developments have been made in recent years on drugs that suppress the virus and its symptoms. In early 2003, a drug called adefovir was reported as an effective treatment. Another drug called tenofovir was demonstrated as effective in patients infected with both hepatitis B and HIV. Two studies also reported on the effectiveness of a drug called Preveon, which was more expensive than others. Patients also should rest in bed as needed, continue to eat a healthy diet, and avoid alcohol. Any non-critical surgery should be postponed. PrognosisEach year an estimated 150,000 persons in the United States get hepatitis B. More than 10,000 will require hospital care, and as many as 5,000 will die from complications of the infection. About 90% of all those infected will have acute disease only. A large majority of these patients will recover within three months. It is the remaining 10%, with chronic infection, who account for most serious complications and deaths from HBV infection. In the United States, perhaps only 2% of all those who are infected will become chronically ill. The course of chronic HBV infection in any particular patient is unpredictable. Some patients who do well at first may later develop serious complications. Even when no symptoms of liver disease develop, chronic carriers remain a threat to others by serving as a source of infection. PreventionThe best way to prevent any form of viral hepatitis is to avoid contact with blood and other body fluids of infected individuals. The use of condoms during sex also is advisable. If a person is exposed to hepatitis B, a serum preparation containing a high level of antibody against HBV may prevent infection if given within three to seven days of exposure. Babies born of a mother with HBV should receive the vaccine within 24 hours. An effective and safe vaccine is available that reliably prevents hepatitis B. Vaccination is suggested for most infants and for children aged 10 and younger whose parents are from a place where hepatitis B is common. Teenagers not vaccinated as children and all adults at risk of exposure also should be vaccinated against hepatitis B. Three doses are recommended. KEY TERMSAntibody— A substance formed in the body in response to a foreign body, such as a virus, which can then attack and destroy the invading virus. Antigen— Part of an invading microorganism, such as a virus, that causes tissue damage (in hepatitis, to the liver), and that also stimulates the body's immune system to produce antibodies. Cirrhosis— The end result of many forms of liver disease, the condition of the liver when its cells have been damaged or destroyed and are replaced by scar tissue. Vaccine— A substance prepared from a weakened or killed virus which, when injected, helps the body to form antibodies that will attack an invading virus and may prevent infection altogether. Those at increased risk of getting hepatitis B, and who therefore should be vaccinated, include:
Studies released in 2003 showed increased risk of nonresponse to hepatitis B vaccines among adults over age 30. This may be related to age-associated changes in the immune system. ResourcesPERIODICALS"Antiviral Effective Against Hepatitis B Virus in HIV-coinfected." Virus Weekly January 28, 2003: 16. Bauer, Jeff. "Co-infection with Hepatitis B and HIV Increases Men's Risks of Death from Liver Disease." RN March 2003: 97. Elliott, William T. "Warfarin Effectively Prevents Venous Thromboembolism (Pharmacology Watch)." Critical Care Alert April 2003. "Hepatitis B Vaccine Loses Effectiveness in Older Adults." Vaccine Weekly January 29, 2003: 23. ORGANIZATIONSHepatitis B Foundation. 101 Greenwood Ave., Suite 570, Jenkintown, PA 19046. (215) 884-8786. 〈info@hepb.org〉. |
|
|
Cite this article
Cramer, David; Odle, Teresa. "Hepatitis B." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. Cramer, David; Odle, Teresa. "Hepatitis B." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1G2-3451600774.html Cramer, David; Odle, Teresa. "Hepatitis B." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3451600774.html |
|
Hepatitis B Vaccine
HEPATITIS B VACCINEHepatitis B vaccine is prepared in one of two ways: by concentrating and inactivating infectious particles in the circulating blood of persons who are hepatitis B carriers, or by using recombinant-DNA technology to artificially produce the antigen in yeast cells. In the United States, only the recombinant-DNA vaccine is currently available. In both processes, the result is a highly purified preparation that induces protection in 90 percent or more of persons who receive three injections, the second following the first by at least one month and the third at least two months after the second. Booster doses are not recommended. Since infection in the newborn period is associated with the highest risk of lifelong carriage of hepatitis B virus and death resulting from liver cirrhosis or cancer, the first dose is commonly given at birth. In the United States and most other countries, universal vaccination of infants with hepatitis B vaccine is recommended. Adolescents and adults who are at increased risk of hepatitis B infection as a result of lifestyle (e.g., injection drug use) or occupation(e.g., health care workers) should also receive the vaccine. No serious adverse effects have been shown to be caused by the vaccine, although the possibility has been raised of an association with Guillain-Barre syndrome (GBS) at a very low rate (approximately 1/200,000 vaccinees). Alan R. Hinman (see also: Communicable Disease Control; Immunizations ) BibliographyCenters for Disease Control and Prevention (1991). "Hepatitis B Virus: A Comprehensive Strategy for Eliminating Transmission in the United States Through Universal Childhood Vaccination: Recommendations of the Advisory Committee on Immunization Practices (ACIP)." Morbidity and Mortality Weekly Report 40:1–25. |
|
|
Cite this article
Hinman, Alan R.. "Hepatitis B Vaccine." Encyclopedia of Public Health. 2002. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. Hinman, Alan R.. "Hepatitis B Vaccine." Encyclopedia of Public Health. 2002. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1G2-3404000422.html Hinman, Alan R.. "Hepatitis B Vaccine." Encyclopedia of Public Health. 2002. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3404000422.html |
|
hepatitis
hepatitis (hep-ă-ty-tis) n. inflammation of the liver caused by viruses, toxic substances, or immunological abnormalities. chronic h. hepatitis that continues for months or years, eventually leading to cirrhosis, caused by persistent infection with a hepatitis virus or by autoimmune disease. h. A (epidemic h.) infectious hepatitis transmitted by contaminated food or drink. After an incubation period of 15–40 days, the patient develops fever and sickness. Yellow discoloration of the skin (see jaundice) appears about a week later and persists for up to three weeks. h. B (formerly serum h.) infectious hepatitis transmitted by infected blood or blood products, contaminated hypodermic needles, blood transfusions, etc., by sexual contact, or by contact with other body fluids. Symptoms, which develop suddenly after an incubation period of 1–6 months, include headache, fever, chills, general weakness, and jaundice. h. C (formerly non-A, non-B h.) infectious hepatitis that has a mode of transmission similar to that of hepatitis B. h. D infectious hepatitis that occurs only with or after infection with hepatitis B and is associated with severe chronic hepatitis. h. E acute hepatitis caused by a virus transmitted by food or drink. infectious h. hepatitis caused by viruses, several types of which have been isolated as specific causes of the disease and can be detected by blood tests.
|
|
|
Cite this article
"hepatitis." A Dictionary of Nursing. 2008. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "hepatitis." A Dictionary of Nursing. 2008. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O62-hepatitis.html "hepatitis." A Dictionary of Nursing. 2008. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-hepatitis.html |
|
Hepatitis
HEPATITISDEFINITIONHepatitis is an inflammation of the liver. At least six forms of hepatitis are now recognized. They are referred to as hepatitis A, B, C, D, E, and G. They vary considerably in severity. Some forms are acute (sudden and brief) and others are chronic (long-lasting). Some forms have little or no long-lasting effects. Others can become life-threatening diseases. DESCRIPTIONThe liver is one of the most important organs in the body. It regulates the amount of many chemicals that occur in the blood. It removes substances from the blood that are or may become toxic. A toxin is a poison. The liver changes these substances into less harmful forms. It then converts them into a form that will dissolve in water. In this form, the substances are eliminated from the body. If the liver is damaged, toxic substances may build up in the bloodstream. In the worst cases, these substances can cause serious illness and even death. Most forms of hepatitis are caused by viruses. The viruses have names similar to those of the diseases they cause. Hepatitis A, for example, is caused by the hepatitis A virus (HAV). Hepatitis B is caused by the hepatitis B virus (HBV), and so on. Hepatitis A and B have been known for many years. At one time they were called infectious and serum hepatitis, respectively. When hepatitis C was first discovered, it was called non-A, non-B hepatitis. It is now known by its simpler name. Hepatitis D, E, and G were discovered during the 1970s, 1980s, and 1990s. Hepatitis AHepatitis A is an acute disorder. An acute disorder is one that comes on suddenly and usually does not last very long. An initial episode of hepatitis A is often followed by a relapse a few weeks later. A relapse is a reoccurrence of the disease. A few people have many relapses. Children are more likely to contract (catch) hepatitis A than adults, but their symptoms are usually much milder than those of adults. Among those at highest risk for hepatitis A are the following:
Hepatitis: Words to Know
Hepatitis BHepatitis B is one of the most common infectious diseases in the world. By some estimates, more than 300 million people worldwide have the disease. Hepatitis B occurs in both acute and chronic forms. The chronic form is one that develops slowly and remains in the body for a long time. The disease may range from mild to severe. Many people infected with HBV never develop any symptoms. They may not know they have the virus in their bodies, but they are still able to pass the virus on to other people. Such people are said to be carriers of the disease. About 1.5 million Americans are thought to be carriers of HBV. In its most serious forms, hepatitis B can be a life-threatening disease. The virus causes severe scarring of the liver. The scarring process is called cirrhosis (pronounced suh-RO-suss) of the liver. Cirrhosis damages the liver so badly that it may no longer be able to function normally. It can cause the death of the patient. Cirrhosis can also lead to liver cancer (see cancer entry). There are three major ways in which hepatitis B can be transmitted. They are:
OTHER FORMS OF HEPATITISTwo other forms of hepatitis are alcoholic hepatitis and autoimmune hepatitis. Both of these disorders result in damage to the liver. They have symptoms similar to those of hepatitis A, B, C, D, E, and G, but they have different causes. Alcoholic hepatitis is caused by an excessive consumption of alcohol over a period of time. Alcohol is largely broken down in the liver. The more alcohol a person drinks, the harder the liver has to work. In some cases, the liver can be damaged by processing too much alcohol. The cure for alcoholic hepatitis is simple: the patient must stop drinking. When the liver has less alcohol to deal with, it may return to its normal condition. Some alcoholics find it difficult to give up drinking. In such cases, they can cause severe damage to their livers. They may develop cirrhosis and/or liver cancer. These diseases are major causes of death among alcoholics. Autoimmune hepatitis occurs when the body's immune system becomes confused. It begins to attack the cells in its own body the way it attacks foreign invaders. Antibodies released by the immune system may attack the liver and cause inflammation. Autoimmune hepatitis can be acute or chronic. Unfortunately, there is no way to cure the disease. Some people eventually recover from the condition, while others become so ill that they die. Hepatitis CHepatitis C was first identified in 1974. The virus that causes the disease was not found until 1989. The infection is sometimes called "transfusion hepatitis." The name comes from one possible cause of the disease. It may be transmitted along with blood used in blood transfusions. Since the identification of HCV, tests have been developed to identify the virus. Blood transfusions are no longer a major cause of the disease. Other ways in which the virus can be transmitted include:
Hepatitis C can occur in either acute or chronic forms. In its acute form, it is quite mild, but in its chronic form it can be even more dangerous than hepatitis B. Among those at highest risk for hepatitis C are:
Hepatitis D, E, and G are relatively less common. They may occur in conjunction with one of the other forms of hepatitis or on their own. CAUSESThe exact mechanism by which viruses cause hepatitis is not entirely understood. It appears that the disease is not caused by the virus itself, but by the body's immune system. The immune system is a network of organs, tissues, cells, and chemicals designed to protect the body against foreign invaders, such as bacteria and viruses. When a foreign invader enters the body, the immune system begins to respond. It produces chemicals designed to kill the invader. These chemicals are called antibodies. The presence of antibodies in the bloodstream may have other effects on the body, including inflammation, swelling, and other symptoms. It appears that the liver becomes inflamed because of the antibodies produced by the immune system, not because of the virus itself. SYMPTOMSThe symptoms of the various forms of hepatitis are similar. They are caused by damage to the liver. Perhaps the most noticeable symptom is jaundice. Jaundice causes a yellowing of the skin. Other symptoms associated with hepatitis include fatigue, general achiness, nausea, mild fever, and loss of appetite. As infection spreads in the liver, the organ becomes enlarged. It may cause pain in the abdomen. In the case of acute hepatitis, these symptoms tend to disappear within a few months. In a very small percentage of cases, symptoms may become worse. In less than 1 percent of cases, the patient's liver may fail completely. Patients then stand only a 50–50 chance of surviving the disease. In cases where symptoms last for at least six months, the patient is said to have chronic hepatitis. Symptoms may continue to get worse. But the worst damage that occurs is cirrhosis of the liver. Cirrhosis leads to liver cancer in somewhat less than 10 percent of all cases. Many people who have been infected with a hepatitis virus show no symptoms at all. In the case of hepatitis B, that number may be as high as 50 percent. Up to three-quarters of all children with hepatitis A never have symptoms of the infection. Although these individuals have no symptoms, they are still carriers of the disease. They can pass the virus on to other individuals. DIAGNOSISThe appearance of jaundice is often the first step in diagnosing hepatitis. The change in color of one's skin is so pronounced that most patients seek medical advice when they have that experience. Confirmation of this diagnosis can be easily obtained with a blood test. A sample of the patient's blood is drawn (taken). The sample is then tested for the presence of viral antigens or viral antibodies. A viral antigen is a part of the virus that causes the body's immune system to react. A viral antibody is the chemical produced by the immune system to destroy the virus. Blood tests for either viral antigens or viral antibodies—or both—are available for all forms of viral hepatitis. TREATMENTThere is no cure for hepatitis. The only approach of value is for patients to get as much bed rest as possible. They should continue to eat and drink as much as possible, but alcoholic drinks should be avoided. PROGNOSISThe prognosis for various forms of hepatitis varies considerably. Most patients with hepatitis A recover completely within a few months. They become immune to HAV and will not contract the disease again. Up to three-quarters of all Americans over the age of fifty have been exposed to HAV. About 90 percent of patients with hepatitis B will also recover completely. Among the remaining 10 percent, however, serious complications are likely to develop. These complications include cirrhosis of the liver and liver cancer. About 2 percent of all patients with hepatitis B become chronically ill with the disease. The prognosis for patients with hepatitis C is slightly less promising. About 15 percent will develop cirrhosis of the liver or liver cancer. Many more are likely to develop chronic hepatitis or some other liver-related disorder. PREVENTIONVaccines have now been developed for two forms of hepatitis, A and B. These vaccines are recommended for individuals who may be at risk for one of these diseases. For example, health care workers and those who plan to travel to areas where hepatitis is common should be vaccinated. Injections are also available for those who have already been exposed to hepatitis A or B. These injections can be very effective if they are given fairly soon after the exposure has occurred. Hepatitis infections can also be prevented by following a number of lifestyle suggestions, including:
FOR MORE INFORMATIONBooksEverson, Gregory T. and Hedy Weinberg. Living with Hepatitis C: Survivor's Guide. New York: Hatherleigh Press, 1998. Rosenthal, M. Sara. The Gastrointestinal Sourcebook. Los Angeles: Lowell House, 1997. Roybal, Beth Ann Petro. Hepatitis C: A Personal Guide to Good Health. Berkeley, CA: Ulysses Press, 1997. Silverstein, Alvin, Virginia Silverstein, and Robert Silverstein. Hepatitis. Hillside, NJ: Enslow Publishers, Inc., 1994. OrganizationsAmerican Liver Foundation. 1425 Pompton Ave., Cedar Grove, NJ 07009. (800) 223–0179. http://sadieo.ucsf.edu/alf/alffinal/homepagealf.html. Hepatitis B Foundation. 101 Greenwood Ave., Suite 570, Jenkitown, PA 19046. (214) 884–8786. http://www.hepb.org. Web sitesHepNet: The Hepatitis Information Network. [Online] http://www.hepnet.com (accessed on February 2, 1998). King, J. W. Bug Bytes. [Online] http://www.ccm.lsumc.edu/bugbytes (accessed on October 25, 1999). |
|
|
Cite this article
"Hepatitis." UXL Complete Health Resource. 2001. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Hepatitis." UXL Complete Health Resource. 2001. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1G2-3437000159.html "Hepatitis." UXL Complete Health Resource. 2001. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3437000159.html |
|
hepatitis
hepatitis Inflammatory liver disease, characterized by jaundice, abdominal pain, and anorexia. May be due to bacterial or viral infection, alcohol abuse, or various toxins. Treatment is usually conservative, with a very low fat diet (secretion of bile is impaired) and complete abstinence from alcohol.
Even after recovery, people may continue to be carriers of the virus, especially for hepatitis B and C, which are transmitted through blood and other body fluids. Liver cancer and cirrhosis are more common among people who have suffered from hepatitis B or C. |
|
|
Cite this article
DAVID A. BENDER. "hepatitis." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. DAVID A. BENDER. "hepatitis." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O39-hepatitis.html DAVID A. BENDER. "hepatitis." A Dictionary of Food and Nutrition. 2005. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-hepatitis.html |
|
Hepatitis, Infectious
Hepatitis, InfectiousHow Common Is Viral Hepatitis? What Are the Signs and Symptoms of Hepatitis? How Do Doctors Make the Diagnosis? What Is the Treatment for Hepatitis? How Can Hepatitis Be Prevented? Hepatitis (heh-puh-TIE-tis) is an inflammation of the liver*. It can have several different causes, most commonly viral infection.
KEYWORDS for searching the Internet and other reference sources Alpha-interferon Cirrhosis Liver disease Sexually transmitted diseases What Is Infectious Hepatitis?The liver plays many important roles in the body. It filters out toxins* and other harmful substances from the blood, stores vitamins and nutrients, regulates cholesterol* production, and helps in the production of many other substances the body needs to function normally. Long-term drug or alcohol abuse, exposure to harmful chemicals or other toxins, various infections, trauma*, and certain medications all can damage the liver and lead to hepatitis. Viruses usually cause infectious hepatitis, although other organisms, such as bacteria or parasites, sometimes can be the culprit as well.
Several different viruses can bring about acute* hepatitis, including at least five known hepatitis viruses (A through E). Among these viruses, hepatitis B (HBV) and C (HCV) cause the most serious disease. Most of the time, people recover fully from viral hepatitis. But in some people HBV and HCV cause chronic* hepatitis, in which the infection remains in the body and the liver does not recover completely from the inflammation. Chronic hepatitis eventually can lead to severe liver damage, liver cancer, and sometimes cirrhosis* of the liver. Other viral infections, such as infectious mononucleosis* or “mono,” which usually is caused by the Epstein-Barr (EP-steen BAR) virus, can produce shortlived, mild hepatitis.
Types of Viral HepatitisHepatitis AAmong the five major types, hepatitis A virus (HAV) causes the most common and least serious form of hepatitis. It typically spreads through eating food or drinking water contaminated with feces* from someone who is infected. Parts of the world with poor sanitation are at greatest risk for outbreaks of the disease. In the United States, cases of HAV infection sometimes arise when food handlers fail to practice good hygiene, such as regularly washing their hands. HAV also can be transmitted during unprotected sexual intercourse.
Hepatitis BHBV infection can lead to chronic hepatitis in up to 10 percent of infected adults and older children, in up to 30 percent of infected children younger than 6 years old, and in up to 90 percent of infants who contract the virus from their infected mothers at birth. It is a more serious form of hepatitis because it can cause long-term or permanent liver inflammation and scarring, liver cancer, and liver failure. HBV can pass easily from person to person through direct contact with infected blood and other body fluids, including semen*, vaginal* fluids, and sometimes saliva. It most often is spread through unprotected sexual intercourse, injection of drugs with contaminated needles, blood transfusions*, kidney* dialysis*, organ transplants, or from a mother to her child during birth. HBV also can be transmitted if improperly sterilized equipment is used during body piercing, tattooing, or circumcision*. Health care workers are advised to take precautions to avoid accidental sticks from needles used in the care of patients, because patients might be infected with the virus.
Hepatitis CLike HBV, HCV can spread through direct contact with infected body fluids, especially blood. HCV most often is transmitted through the sharing of needles by injection drug users. In the United States, up to 90 percent of cases occur this way. Patients receiving long-term dialysis for kidney failure are also at relatively higher risk of HCV infection. The infection can result in long-lasting complications. About 80 percent of those who contract HCV may develop chronic hepatitis, which can put them at risk for other forms of serious liver disease. HCV infection is the most common reason for liver transplants in the United States. Hepatitis DHepatitis D virus (HDV) infection is found only in those who also have been infected with HBV. HDV is passed from person to person in the same way as HBV. Co-infection can transform a mild HBV infection or an infection that has no symptoms at all into a more serious, rapidly progressing disease. HDV usually spreads through contact with infected blood, most often from injection drug use with contaminated needles. Hepatitis ELike HAV, hepatitis E virus (HEV) is transmitted through drinking water contaminated with infected feces. HEV infection occurs most often in underdeveloped countries with poor sanitation. How Common Is Viral Hepatitis?Infectious hepatitis is common all over the world. Each year HAV infects up to 1.4 million people worldwide, including about 250,000 Americans. Most cases in the United States are seen in children less than 10 years of age. According to the U.S. Centers for Disease Control and Prevention (CDC), at least 80,000 people in the United States are infected with HBV each year, and about 5,000 die from the disease annually. Africa and parts of South America and Asia, especially the Middle East, all have high rates of HAV and HBV infection. The World Health Organization (WHO) estimates that there are 170 million people infected with HCV around the globe, with 3 million to 4 million new cases appearing annually. About 4 million people in the United States have HCV, with about 25,000 new cases diagnosed each year. What Are the Signs and Symptoms of Hepatitis?Common symptoms of all forms of acute infectious hepatitis include extreme tiredness, loss of appetite, fever, headache, muscle and joint aches, nausea, vomiting, diarrhea, jaundice*, and stomach pain. Bowel movements may look pale in color, and urine may become dark, so that it looks like tea. Children infected with HAV frequently have few or no signs of illness, and people with HCV infection often show no symptoms or have only mild symptoms like those of the flu until the disease has caused serious liver damage.
How Do Doctors Make the Diagnosis?Hepatitis is diagnosed by blood tests, which can show that the liver is inflamed and indicate how well it is working. Blood tests can also reveal which type of hepatitis virus is causing the disease. When a person is very ill from hepatitis or remains sick for a long time, a biopsy* of the liver may be done to determine whether the liver is becoming damaged or scarred.
What Is the Treatment for Hepatitis?Treatment for viral hepatitis depends on its cause and how sick the patient is. Hepatitis A and EPeople with HAV and HEV infection usually recover completely without needing hospitalization. They can take care of themselves at home by making sure they get enough rest and drink plenty of fluids. Doctors advise avoiding alcohol and drugs, because these substances can stress an already inflamed liver. Hepatitis B and CMost of the time, HBV and HCV infection can be monitored with blood tests that look for liver inflammation and measure liver function. In severe cases of viral hepatitis, hospitalization may be necessary, especially when the liver is damaged and stops working well. Medications, including alpha-interferon (AL-fa in-ter-FEER-on) injections, may be given to help the body’s immune system fight chronic hepatitis B, C, and D. It is recommended that people who have chronic infectious hepatitis live a healthy lifestyle by avoiding alcohol, getting enough sleep, exercising regularly, and eating a nutritious diet. These measures reduce stress on the liver and can prevent or slow the progression of long-term liver disease. What to ExpectPeople typically recover completely from HAV or HEV infection within about 2 months, but sometimes it takes longer. Those infected with HBV or HCV usually recover within 6 months. Cases of chronic viral hepatitis can last for decades or even a lifetime. HBV and HCV can lead to scarring of the liver, liver cancer, liver failure, and sometimes death. A liver transplant may be required in cases that progress to liver failure. How Can Hepatitis Be Prevented?A vaccine* exists for HAV, but it is not used routinely in the United States, except in areas where the number of cases is consistently high, as seen in several western states. The vaccine is recommended for certain laboratory workers, anyone who has more than one sexual partner or who engages in other high-risk types of behavior, or people traveling to underdeveloped areas of the world with poor sanitation. People who come into contact with HAV can be treated with immune globulin*, which is more than 85 percent effective in preventing HAV infection if treatment begins within 2 weeks after exposure to the virus. The best way to prevent HAV and HEV is to practice good hygiene, such as frequent hand washing. Avoiding areas of poor sanitation and unwashed or uncooked food, particularly while traveling, can limit the risk of infection as well.
Today, infants in the United States typically are vaccinated against HBV by age 2 years. Infants born to mothers with HBV infection generally are given immediate injections of HBV immune globulin and receive their first dose of the HBV vaccine within 12 hours of birth. It is recommended that all teens and adults who are at high risk of exposure to infected body fluids, such as health care workers, receive the HBV vaccine. Since HDV infects only those who already have HBV, vaccination against HBV can prevent HDV as well. Using latex condoms for all forms of sexual intercourse also can help protect against HBV. Avoiding intravenous drug use and sharing of razors, toothbrushes, or needles, even for tattoos or body piercing, can help prevent both HBV and HCV. Since 1992 blood banks in the United States have screened donated blood for HBV and HCV. Currently, there is no vaccine for HCV. See also ResourcesOrganizationsAmerican Liver Foundation, 75 Maiden Lane, Suite 603, New York, NY 10038. The American Liver Foundation is a national nonprofit organization dedicated to the prevention, treatment, and cure of hepatitis and other liver diseases. It posts articles on liver health at its website. Telephone 800-465-4837 http://www.liverfoundation.org Hepatitis Foundation International, 504 Blick Drive, Silver Spring, MD 20904. The Hepatitis Foundation International offers information on hepatitis at its website, as well as counseling via its toll-free hotline. Telephone 800-891-0707 http://www.hepfi.org WebsiteKidsHealth.org. KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children’s health. It contains articles on a variety of health topics, including hepatitis. |
|
|
Cite this article
"Hepatitis, Infectious." Complete Human Diseases and Conditions. 2008. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Hepatitis, Infectious." Complete Human Diseases and Conditions. 2008. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1G2-3497700199.html "Hepatitis, Infectious." Complete Human Diseases and Conditions. 2008. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3497700199.html |
|
Hepatitis
HepatitisHepatitis A: How Does It Spread? Hepatitis A: How Is It Prevented? Hepatitis B and C: How Do They Spread? Hepatitis C: How Is It Prevented? What Are the Symptoms of Hepatitis? Hepatitis (hep-a-TY-tis) is inflammation* of the liver, an abnormal condition that harms liver cells. It usually is caused by the hepatitis A, B, or C virus and may be acute* or chronic*, mild or extremely serious. Hepatitis also can be caused by other germs, by toxic chemicals, or by certain medications. KEYWORDS for searching the Internet and other reference sources Cirrhosis Hepatic necrosis Inflammation Jaundice Liver transplant
What Is Hepatitis?The liver, a red-brown, wedge-shaped organ in the upper abdomen, is the largest internal organ in the body and performs the widest range of jobs. It gets rid of harmful substances in food, disposes of old blood cells, helps digest fat, produces chemicals to make the blood clot, and makes sure the blood carries the right balance of fat, sugar, and amino (a-ME-no) acids (the building blocks of proteins) to all the cells of the body. Complex as it is, the liver is also open to a wide range of problems. Many of these fall under the heading “hepatitis,” a general term that means the liver is experiencing inflammation. Hepatitis can be caused by many things: excessive drinking of alcohol, overdoses or side effects of medication, inhaling of toxic chemicals, or problems with a person’s immune system*. It can also result from infection with a range of microbes.
Most hepatitis is caused by infection with a hepatitis virus*, usually the hepatitis A, B, or C virus. Each one can cause acute viral hepatitis, an inflammation of the liver that usually lasts 4 to 6 weeks. Typically, people who have acute viral hepatitis feel exhausted, and their skin and the whites of their eyes take on a yellowish tint, a condition called jaundice (JAWN-dis). In rare cases, acute viral hepatitis can develop into a life-threatening illness called fulminant* hepatitis. But usually it is milder, and the person recovers without needing special care. Often, viral hepatitis causes no symptoms at all.
Hepatitis B and C, however, can do long-term damage as well. About 75 to 85 percent of people infected with hepatitis C (and 5 to 10 percent of those infected with hepatitis B) cannot fight off the virus. They become infected chronically, meaning the virus remains active in their body for more than 6 months. In most cases, the infection lasts for decades. Because the liver is large and resilient, it usually keeps working well despite the virus. In fact, most people with chronic hepatitis live a normal life span and do not even realize that they have the infection. But after 10, 20, 30, or more years, some people with chronic infections eventually will have serious liver damage, such as cirrhosis (si-RO-sis), or scarring of the liver. These unlucky people also have a much greater than normal risk of developing a kind of liver cancer* called hepatocellular carcinoma (hep-a-to-SEL-yoo-lar kar-si-NO-ma). Cirrhosis and liver cancer are both serious, often fatal illnesses.
In the United States, hepatitis C is second only to alcohol abuse as a cause of liver damage and is the leading reason people get liver transplants*. Hepatitis C is less likely to cause a noticeable acute illness than hepatitis B, so that most people do not know they have it, but it is more likely to lead to a chronic infection.
Worldwide, hepatitis C is believed to infect 170 million people, and health officials fear it will cause major public health problems in the future. Yet HCV, as it is called, is not as well-known as many rarer diseases. The virus was not identified until 1988, and much remains to be learned about how it behaves. One of its apparent effects is to make alcohol more toxic to the liver: many people with liver damage from alcohol turn out to have hepatitis C as well. In addition to hepatitis A, B, and C, scientists have identified three less-common hepatitis viruses:
Hepatitis A: How Does It Spread?Every now and then, local news reports will tell of an outbreak of hepatitis. Often, the announcers will say that people who ate in a certain restaurant or attended a certain nursery school in the last few weeks should consult their doctor to see about preventing infection. Hepatitis A is the virus that causes that kind of outbreak. Sometimes called infectious hepatitis, it is highly contagious*, but it almost never does permanent damage. In the United States, hepatitis A most commonly is spread in day care centers to young children and their parents. It spreads by what doctors call the “fecal-oral route.” Virus in the feces (stool) of an infected person somehow gets into the mouth of someone else. This can happen if people fail to wash their hands after changing a diaper or using the toilet and then go on to prepare or serve food. Or one toddler may handle another’s cup or pacifier. In addition, sewage that is not treated properly can contaminate water supplies. Shellfish from contaminated waters can spread the virus if eaten raw or undercooked.
Once people have recovered from hepatitis A, it is over. They are not “carriers” of the virus and cannot infect anyone else. Hepatitis A: How Is It Prevented?Good hygiene, including washing hands after using the toilet and before handling food, can prevent hepatitis A. Vaccination* against hepatitis A also is available. It is recommended for children and adults traveling to developing countries, for children in communities with high rates of hepatitis A, such as among people of Native American ancestry, and for children who live in states with above-average levels of the disease.
Once people have been exposed to the virus, infection often can be prevented by an injection of immune globulin (GLOB-yoo-lin), a substance that helps the immune system. But the globulin must be given within two weeks of exposure to the virus. Hepatitis B and C: How Do They Spread?Hepatitis B and C are spread chiefly by contact with an infected person’s blood. People with chronic hepatitis B and C are “carriers,” meaning their blood can transmit the virus to others even if they have no symptoms of illness. In the United States, these viruses spread most commonly when intravenous (in-tra-VEE-nus) drug users share needles. About 90 percent of people who inject illegal drugs are believed to be infected with hepatitis C, for instance. Accidental needle sticks, a risk to health care workers, can also spread these viruses. So can organ transplants, tattooing, body piercing, and sharing razors, toothbrushes, or other objects that may have small amounts of blood on them. Transfusions (trans-FEW-zhunz) of infected blood used to be the biggest source of infection. People with hemophilia (he-mo-FIL-e-a), a blood-clotting problem, were especially likely to be infected when they got blood products drawn from large numbers of donors. Today, however, donors and blood in the United States are screened for both hepatitis B and C, and the risk of getting them from a transfusion is extremely low. But anyone who got a transfusion before July 1992 should be tested for hepatitis C. The U.S. and the World In the United States, 4 million people (or 1.8 percent of the population) are estimated to have chronic hepatitis C, and 8,000 to 10,000 people a year die of it. An estimated 1 million to 1.5 million people have chronic hepatitis B, and 5,000 to 6,000 people a year die of it. Worldwide, hepatitis B is more common, with 400 million people infected. In Southeast Asia and sub-Saharan Africa, where chronic hepatitis B is most common, 10 to 25 percent of all people may carry the virus. Hepatocellular carcinoma, the liver cancer linked to chronic hepatitis, is also most common in these areas. Worldwide, an estimated 170 million people have chronic hepatitis C. In the United States, hepatitis B is most common in young adults (intravenous drug users, health care workers, prison inmates, and people, especially homosexual men, who have sex with many partners). In developing countries, hepatitis B is most common in infants and young children, who get it from their mothers or within the family. When hepatitis B infects a child, it is much more likely to become chronic. That is why chronic B is more common in Asia and Africa than in the United States. Hepatitis B is more contagious than hepatitis C. It is also more contagious than HIV, the virus that causes AIDS*. Hepatitis B spreads readily through sexual contact. Women and men, especially homosexual men, who have sex with many partners are at increased risk.
Hepatitis C is less likely to spread through sexual contact, although it is not clear exactly how easily it spreads this way. In several studies of marriages where one partner is infected with hepatitis C, the other partner does not seem to have an increased risk of getting it. But people who have sex with many partners seem to run a greater risk of infection. Women appear more likely to get hepatitis C from men than vice versa. Hepatitis B, and more rarely hepatitis C, can also spread from infected mothers to newborns. Finally, in more than 10 percent of hepatitis C cases, there is no obvious source of infection. It is possible that some means of transmission has yet to be identified. Neither hepatitis B nor C, however, are known to spread through air, water, or food. A person cannot catch them by being near infected people or by hugging, working, going to school, or swimming with infected people. How Is Hepatitis B Prevented?A vaccine can prevent hepatitis B. Since 1991, U.S. health officials have recommended that all newborns receive the necessary three injections. All children ages 11 or 12 should be vaccinated if they did not get the shots as babies. This, officials hope, may virtually eliminate the disease in the youngest generation of Americans. The vaccine is also recommended for everyone at high risk, including health care workers, people who have had sex with multiple partners, and anyone who lives with, has sex with, or takes care of a person who has hepatitis B. Once a person has been exposed to hepatitis B, speedy treatment with hepatitis B immune globulin (HBIG), coupled with vaccination, sometimes can prevent infection in adults. When mothers have hepatitis B, immediate treatment of their newborns can prevent the babies from developing chronic hepatitis. For people who have not been vaccinated, hepatitis B can be prevented by not having unprotected sex, using condoms, and not using intravenous drugs. In addition, people should avoid contact with blood. They should not share razors, toothbrushes, or any items that have even the slightest amount of blood on them. Infected people should cover any wounds they may have and should dispose of or wash any tissues, clothes, or sanitary napkins that may contain their blood. Hepatitis C: How Is It Prevented?There is no vaccine for hepatitis C, and there is no reliable treatment after a person is exposed. Prevention consists of not sharing needles, avoiding contact with blood, limiting sexual contact, and using condoms, as with hepatitis B. What Are the Symptoms of Hepatitis?Acute hepatitis can cause loss of appetite, nausea, vomiting, fatigue, fever, jaundice, darkening of the urine, abdominal pain, arthritis (ar-THRY-tis; joint pain), and skin rash. Often symptoms are absent or so mild they go unnoticed. The incubation* period is 15 to 45 days for hepatitis A, 15 to 150 days for hepatitis C, and 50 to 180 days for hepatitis B.
Chronic hepatitis can cause loss of appetite, tiredness, low-grade fever, and a general sense of “not feeling well” that doctors call malaise (ma-LAZE). Again, there are often no symptoms. If the illness causes liver damage, additional symptoms can include weakness, weight loss, itching of the skin, enlargement of the spleen*, fluid in the abdomen, and a pattern of red blood vessels showing through the skin.
In severe cases, massive bleeding can occur in the stomach and the esophagus*, which requires emergency treatment. If the liver is no longer able to remove toxins from food, the brain can be affected, causing drowsiness, confusion, and even coma*.
How Is Hepatitis Diagnosed?Viral hepatitis is diagnosed on the basis of symptoms and several kinds of blood tests. Liver enzyme tests indicate whether the liver is inflamed. If it is, other blood tests can look for specific evidence of hepatitis B or C and can help doctors distinguish between acute and chronic cases. In chronic cases, doctors may look for liver damage by doing a biopsy (BY-op-see), in which a sample of the liver is removed by a needle through the skin and examined under a microscope. In many cases, the first hint of hepatitis comes when a routine blood test done for a physical shows signs of abnormalities in the liver. In other cases, a person may try to donate blood and be rejected after his or her blood is tested. How Is Hepatitis Treated?For acute hepatitis, there is no specific treatment. In severe cases, people may be hospitalized to get proper fluids, fever control, and nursing care. For chronic viral hepatitis, the main treatment for years has been interferon alpha (in-ter-FEER-on AL-fa), a naturally occurring substance that interferes with the viruses’ ability to reproduce themselves. Treatment requires injections three times a week for at least 6 months and often causes flulike symptoms or more serious side effects. People often relapse after treatment, which does not eliminate the virus completely.
Hepatitis A Vaccine The vaccine for hepatitis A is thought to provide protection for at least 20 years, although the protection may last for life. The vaccine is administered in two or three doses during a 6-month interval. The vaccine was tested in Thailand on children living in an area with a high rate of infection. More than 40,000 children aged 1 to 6 were given the vaccine in two or three doses. The children who received two doses achieved 94 percent protection, and those receiving three doses had almost 100 percent protection. In the cases that did occur, the symptoms were milder and lasted a shorter time. People who are planning to travel to areas known to have hepatitis A should discuss vaccination with their doctors. Among those who may be candidates for the vaccine are: Military personnel
In recent years, though, research has been yielding some promising new treatments. A drug called lamivudine, which was developed to treat HIV, also appears to be effective in treating chronic hepatitis B. For chronic hepatitis C, a combination of interferon alpha and a drug called ribavirin (ry-ba-VY-rin) seems to be more effective than interferon alone. Several other treatments are being studied. People with chronic hepatitis need to be monitored closely by doctors, who may want to see them at least once or twice a year. Doctors will do liver enzyme tests to see how well the liver is functioning and may get blood tests, sonograms*, or even liver biopsies to check for cancer.
In cases of liver cancer or cirrhosis, sometimes the only treatment is a liver transplant, in which a person s damaged liver is replaced with a healthy organ taken from a deceased person. If the person can get a new liver in time, which is not always possible, such transplants usually are successful, although the virus eventually may damage the new liver as well. Living with Chronic HepatitisMost people with chronic hepatitis do fine. They can go to school, play sports, work, have children, and live a life like anyone else’s. They need to make sure, however, that they do not put any extra stress on their liver. In the view of most experts, that means that they should never drink alcoholic beverages. They should not take any medicines, even common over-the-counter or herbal remedies, unless they specifically are approved by their doctor. They should not use illegal drugs. In most cases, they should be vaccinated against hepatitis A and against hepatitis B, unless they already have it. As with other chronic illnesses, people with hepatitis often struggle with feelings of grief, worry, and isolation. Some feel a stigma because their illness often is associated with drug abuse, even though there are many other ways of getting it. Because most people know little about hepatitis, friends and even family may have unrealistic fears about catching it and may avoid the infected person. Counseling for the entire family sometimes can help. The illness and sometimes the treatment can also cause fatigue and depression*. Infected people may need to get help from family and friends, seek treatment for depression, or modify their schedules to take it easier. Many groups now offer advice, support, and solidarity for people with chronic hepatitis.
Hepatitis without a Virus Not all hepatitis is caused by a virus. It can also be caused by toxic chemicals such as carbon tetrachloride, a solvent used in some dry-cleaning fluids, or by some medications. Many common medications, such as Dilantin (dy-LAN-tin) for epilepsy (EP-i-LEP-see) and isoniazid (i-so-NY-a-zid) for tuberculosis (too-ber-ku-LO-sis), cause hepatitis in a small fraction of the people who take them. But once the drug is stopped, the liver recovers. Life-threatening hepatitis can result, however, if a person accidentally or intentionally takes an overdose of many medicines, including the common over-the-counter pain reliever acetaminophen (a-set-a-MEE-no-fen). Finally, some people experience a chronic condition called autoimmune hepatitis. In such people, it appears, the body’s immune system attacks its own liver cells. Although treatment with corticosteroids* can improve the condition, it is often fatal unless a liver transplant is performed.
See also ResourcesBooksEverson, Gregory T., and Hedy Weinberg. Living with Hepatitis C: A Survivor’s Guide, revised edition. New York: Hatherleigh Press, 1999. A clear, detailed, and encouraging book from a doctor who has treated hundreds of hepatitis C patients and a writer who has hepatitis C herself. Turkington, Carol. Hepatitis C: The Silent Killer. Chicago: Contemporary Books, 1998. OrganizationsU.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road N.E., Atlanta, GA 30333. The U.S. government authority for information about infectious and other diseases, the CDC’s Hepatitis Branch has a hotline and posts information about hepatitis at its website. Telephone 888-443-7232 http://www.cdc.gov/ncidod/diseases/hepatitis/index.htm The World Health Organization (WHO), Avenue Appia 20, 1211 Geneva 27, Switzerland. This group’s website posts a fact sheet about hepatitis. http://www.who.int/emc/diseases/hepatiti/index.html The Hepatitis Information Network offers a large amount of well-presented information on its website. http://www.hepnet.com |
|||||||||||||||||||||||||||||||||||||||||||
|
Cite this article
"Hepatitis." Complete Human Diseases and Conditions. 2008. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Hepatitis." Complete Human Diseases and Conditions. 2008. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1G2-3497700198.html "Hepatitis." Complete Human Diseases and Conditions. 2008. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3497700198.html |
|||||||||||||||||||||||||||||||||||||||||||
hepatitis
hepatitis Inflammation of the liver, usually due to a generalized infection. Early symptoms include lethargy, nausea, fever and muscle and joint pains. Five hepatitis viruses are known: A, B, C, D and E. The most common single cause is the hepatitis A virus (HAV). More serious is infection with the hepatitis B virus (HBV), which can lead to chronic inflammation or complete failure of the liver and, in some cases, to liver cancer.
|
|
|
Cite this article
"hepatitis." World Encyclopedia. 2005. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "hepatitis." World Encyclopedia. 2005. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O142-hepatitis.html "hepatitis." World Encyclopedia. 2005. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-hepatitis.html |
|
hepatitis
hep·a·ti·tis / ˌhepəˈtitis/ • n. a disease characterized by inflammation of the liver. |
|
|
Cite this article
"hepatitis." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "hepatitis." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O999-hepatitis.html "hepatitis." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-hepatitis.html |
|
hepatitis
hepatitis
•Attis, gratis, lattice
•malpractice, practice, practise
•Atlantis, mantis
•pastis
•Lettice, lettuce, Thetis
•apprentice, compos mentis, in loco parentis, prentice
•Alcestis, testis
•poetess • armistice
•appendicitis, arthritis, bronchitis, cellulitis, colitis, conjunctivitis, cystitis, dermatitis, encephalitis, gastroenteritis, gingivitis, hepatitis, laryngitis, lymphangitis, meningitis, nephritis, neuritis, osteoarthritis, pericarditis, peritonitis, pharyngitis, sinusitis, tonsillitis
•epiglottis, glottis
•solstice
•mortise, rigor mortis
•countess • viscountess
•myosotis, notice, Otis
•poultice • justice • giantess • clematis
•Curtis • interstice • Tethys
•Glenrothes • Travis
•Jarvis, parvis
•clevis, crevice, Nevis
•Elvis, pelvis
•Avis, Davies, mavis
•Leavis • Divis • novice • Clovis
•Jervis, service
•marquess, marquis
|
|
|
Cite this article
"hepatitis." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "hepatitis." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O233-hepatitis.html "hepatitis." Oxford Dictionary of Rhymes. 2007. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-hepatitis.html |
|