| hepatitis A | <virology> A form of viral hepatitis, known as infectious hepatitis, due to its ability to be spread through personal contact with oral secretions or stool. Virus will be shed in the stools of an infected individual 2-3 weeks prior to the onset of any symptoms. Hepatitis A may also be transmitted sexually. Symptoms are similar to those of influenza, but the skin and eyes may become yellow. Recent travel to a third world country is a risk factor. There is no specific treatment but infected individuals should avoid potentially hepatotoxic substances. The virus is a small (27nm diameter) single stranded RNA virus with some resemblance to enteroviruses such as polio. (27 Sep 1997) |
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| hepatitis a immunization | When immediate protection against hepatitis a (infectious hepatitis) is needed, immunoglobulins are used. Protection is effective only if given within 2 weeks of exposure and lasts but 2-4 months. Immunoglobulins can be used to protect household contacts of someone with acute viral hepatitis and travelers to regions with poor sanitation and high hepatitis a rates, when the traveler has to depart sooner than the vaccines can take effect (about 2 weeks). Travelers can receive the immunoglobulin and vaccine simultaneously and be protected immediately and for longer term. When immediate protection is not needed, hepatitis a vaccines are considered for individuals in high-risk settings, including frequent world travelers, sexually active individuals with multiple partners, homosexual men, individuals using illicit drugs, employees of daycare centres, and certain healthcare workers, and sewage workers. Two hepatitis a vaccines called havrix and vaqta are commercially available in the u.s. Both are highly effective and provide protection even after only one dose. Two doses are recommended for adults and 3 doses for children (under 18 years of age) to provide prolonged protection. (12 Dec 1998) |
| hepatitis A virus | <virology> An RNA virus (hepatovirus) in the family Picornaviridae, that is the causative agent of viral hepatitis type A. The virus replicates in hepatocytes and is presumed to reach the intestine via the bile duct. Transmission occurs by the faecal-oral route. Synonym: infectious hepatitis virus. (20 Sep 2002) |
| hepatitis agents, gb | Proposed members of the family flaviviridae. Gbv-b causes hepatitis in tamarins and possibly humans, and is the putative aetiological agent of a non-(a-e) hepatitis, gb hepatitis. (12 Dec 1998) |
| hepatitis antibodies | Immunoglobulins raised by any form of viral hepatitis; some of these antibodies are used to diagnose the specific kind of hepatitis. (12 Dec 1998) |
| hepatitis antigens | Antigens from any of the hepatitis viruses including surface, core, and other associated antigens. (12 Dec 1998) |
| hepatitis B | <virology> A form of viral hepatitis, known as serum hepatitis, because it is commonly spread through contact with infected blood products (transfusion). May also be spread sexually or from mother to infant. Hepatitis B can cause a much more severe infection than hepatitis A and can occur as an asymptomatic carrier state, a chronic infection or as cirrhosis of the liver. Those at risk (IV drug abusers, health care workers, dialysis patients, transfusion recipients, homosexuals) should be immunised with hepatitis B vaccine. The virus is 42nm diameter, with an outer sheath enclosing inner 27nm core particle containing the circular viral DNA. Aggregates of the envelope proteins are found in plasma and are referred to as hepatitis B surface antigen (HBsAg, previously called Australia antigen). The virus can persist for long periods (and in asymptomatic carriers), association of integrated virus with hepatocellular carcinoma is now well established. (27 Sep 1997) |
| hepatitis B antibodies | <immunology> Antibodies to the hepatitis b antigens, including antibodies to the surface (Australia) and core of the dane particle and those to the "e" antigens. (12 Dec 1998) |
| hepatitis B antigen | Antigens of the virion of the hepatitis b virus or the dane particle, its surface, core and other associated antigens, like the hbe antigen. (12 Dec 1998) |
| hepatitis B core antigen | <virology> (HBcAb, HBcAg), the antigen found in the core of the Dane particle (which is the complete virus) and also in hepatocyte nuclei in hepatitis B infections. (05 Mar 2000) |
| hepatitis B e antigen | (HBeAb, HBe, HBeAg), an antigen, or group of antigen's, associated with hepatitis B infection and distinct from the surface antigen (HBsAg) and the core antigen (HBcAg); it is associated with the viral nucleocapsid. Its presence indicates that the virus is replicating and the individual is potentially infectious. (05 Mar 2000) |
| hepatitis b e antigens | A closely related group of antigens found in the plasma only during the infective phase of hepatitis b or in virulent chronic hepatitis b, probably indicating active virus replication; there are three subtypes which may exist in a complex with immunoglobulins g. (12 Dec 1998) |
| hepatitis b immunization | Hepatits B (hep B) vaccine gives prolonged protection, but 3 shots over a half year are usually required. In the u.s., all infants receive hep b vaccine. Two vaccines (engerix-b, and recombivax-hb) are available in the us. The first dose of hep b vaccine is frequently given while the newborn is in the hospital or at the first doctor visit following birth. The second dose is given about 30 days after the initial dose. A booster dose is performed approximately six months later. Babies born to mothers testing positive for hep b receive, in addition, hbig (hep b immune globulin) for prompt protection. Older children (11-12 years) are advised to receive a hep b booster as are adults in high-risk situations including healthcare workers, dentists, intimate and household contacts of patients with chronic hep b infection, male homosexuals, individuals with multiple sexual partners, dialysis patients, iv drug users, and recipients of repeated transfusions. Healthcare workers accidentally exposed to materials infected with hep b (such as needle sticks), and individuals with known sexual contact with hep b patients are usually given both hbig and vaccine to provide immediate and long term protection. (12 Dec 1998) |
| hepatitis B surface antigen | <virology> A serologic marker on the surface of the hepatitis B virus. The body will normally produce antibodies to hepatitis B surface antigen as part of the normal immune response to infection. It is the presence of antibodies to the hepatitis B surface antigen that are detected in a positive hepatitis B blood test. (27 Sep 1997) |
| hepatitis b surface antigens | Those hepatitis b antigens found on the surface of the dane particle and on the 20 nm spherical and tubular particles. Several subspecificities of the surface antigen are known. These were formerly called the Australia antigen. (12 Dec 1998) |