| viral fusion proteins | Proteins, usually glycoproteins, found in the viral envelopes of a variety of viruses. They promote cell membrane fusion and thereby may function in the uptake of the virus by cells. (12 Dec 1998) |
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| viral gastroenteritis | <pathology> An inflammatory condition of the intestines that results from an infection with a virus. Rotavirus is a common cause. Abdominal pain, diarrhoea, nausea and vomiting are common symptoms. (27 Sep 1997) |
| viral haemagglutination | The nonimmune agglutination of suspended red blood cells by certain of a wide range of otherwise unrelated viruses, usually by the virion itself but in some instances by products of viral growth, the species of erythrocyte agglutinated differing with the different viruses. See: haemagglutination inhibition. (05 Mar 2000) |
| viral haemorrhagic fever | An epidemic viral illness seen in southern Sudan and Zaire, caused by the Ebola virus. The illness is characterised by fever, malaise, muscle aches, respiratory symptoms, diarrhoea, vomiting, epistaxis, haemoptysis, haematemesis, rash, tremors and subconjunctival haemorrhages. Transmitted by close bodily contact with infected individuals (blood, faeces and body fluids). Incubation is-21 days with initial symptoms of fever and headache. There is no specific treatment and death can occur within 10 days. (27 Sep 1997) |
| viral haemorrhagic fever virus | <virology> An epidemic viral illness seen in southern Sudan and Zaire, caused by the Ebola virus. The illness is characterised by fever, malaise, muscle aches, respiratory symptoms, diarrhoea, vomiting, epistaxis, haemoptysis, haematemesis, rash, tremors and subconjunctival haemorrhages. Transmitted by close bodily contact with infected individuals (blood, faeces and body fluids). Incubation is-21 days with initial symptoms of fever and headache. There is no specific treatment and death can occur within 10 days. (27 Sep 1997) |
| viral hepatitis | Liver inflammation caused by viruses. Specific hepatitis viruses have been labelled a, b, c, d, e, f, and g. While other viruses can also cause hepatitis, their primary target is not the liver. (12 Dec 1998) |
| viral hepatitis type A | A virus disease with a short incubation period (usually 15 to 50 days), caused by hepatitis A virus, a member of the family Picornaviridae, often transmitted by faecal-oral route; may be inapparent, mild, severe, or occasionally fatal and occurs sporadically or in epidemics, commonly in school-age children and young adults; necrosis of periportal liver cells with lymphocytic and plasma cell infiltration is characteristic and jaundice is a common symptom. Synonym: epidemic hepatitis, hepatitis A, infectious hepatitis, MS-1 hepatitis, short incubation hepatitis, virus A hepatitis. (05 Mar 2000) |
| viral hepatitis type B | A virus disease with a long incubation period (usually 50 to 160 days), caused by hepatitis B virus, a DNA virus and member of the family Hepadnoviridae, usually transmitted by injection of infected blood or blood derivatives or by use of contaminated needles, lancets, or other instruments; clinically and pathologically similar to viral hepatitis type A, but there is no cross-protective immunity; HBsAg is found in the serum and the hepatitis delta virus occurs in some patients. Synonym: hepatitis B, serum hepatitis, transfusion hepatitis, virus B hepatitis. (05 Mar 2000) |
| viral hepatitis type C | Principal cause of non-A, non-B posttransfusion hepatitis caused by an RNA virus that may be related to Flaviviridae family. Synonym: hepatitis C, virus C hepatitis. (05 Mar 2000) |
| viral hepatitis type D | Acute or chronic hepatitis caused by the hepatitis delta virus, a defective RNA virus requiring HBV for replication. The acute type occurs in two forms: 1) coinfection, the simultaneous occurrence of hepatitis B virus and hepatitis delta virus infections, which usually is self-limiting; 2) superinfection, the appearance of hepatitis delta virus infection in a hepatitis B virus carrier, which often leads to chronic hepatitis The chronic type appears to be more severe than other types of viral hepatitis. Synonym: delta hepatitis, hepatitis D. (05 Mar 2000) |
| viral hepatitis type E | Hepatitis caused by a nonenveloped, single-stranded, positive-sense RNA virus 27-34 nm in diameter, unrelated to other hepatitis; it is the principal cause of enterically transmitted, waterborne, epidemic NANB hepatitis occurring primarily in Asia and Africa. Synonym: hepatitis E. (05 Mar 2000) |
| viral hepatitis vaccines | Any vaccine raised against any virus or viral derivative that causes hepatitis. (12 Dec 1998) |
| viral infection | The successful invasion, establishment and growth of viruses in the tissues of the host. (27 Sep 1997) |
| viral interference | A phenomenon in which infection by a first virus results in resistance of cells or tissues to infection by a second, unrelated virus. (12 Dec 1998) |
| viral load | The number of viral particles (usually HIV) in a sample of blood plasma. HIV viral load is increasingly employed as a surrogate marker for disease progression. It is measured by PCR and bDNA tests and is expressed in number of HIV copies or equivalents per millilitre. (09 Oct 1997) |