virus /vi·rus/ (vi´rus) [L.] a minute infectious agent which, with certain exceptions, is not resolved by the light microscope, lacks independent metabolism and is able to replicate only within a living host cell; the individual particle (virion) consists of nucleic acid (nucleoid)—DNA or RNA (but not both)—and a protein shell (capsid), which contains and protects the nucleic acid and which may be multilayered.
Virus
virus
virus,
virus (vī´rus),
virus
Patient discussion about Toscana virus.
attenuated virus one whose pathogenicity has been reduced by serial passage or other means.
Bayou virus a virus of the genus Hantavirus that causes hantavirus pulmonary syndrome in the southwestern United States.
BK virus (BKV) a human polyomavirus that causes widespread infection in childhood and remains latent in the host; it is believed to cause hemorrhagic cystitis and nephritis in immunocompromised patients.
Central European encephalitis virus a species of tick-borne viruses of the genus Flavivirus that includes the agents of Central European encephalitis and the Russian spring-summer encephalitis virus.
cowpox virus a virus of the genus Orthopoxvirus that is the etiologic agent of cowpox.
Coxsackie virus coxsackievirus.
defective virus one that cannot be completely replicated or cannot form a protein coat; in some cases replication can proceed if missing gene functions are supplied by other viruses; see helper v.
dengue virus a flavivirus existing as four distinct types (designated 1, 2, 3, and 4) that causes dengue.
DNA virus one whose genome consists of DNA.
eastern equine encephalomyelitis virus see equine encephalomyelitis v.
EB virus Epstein-Barr v.
Ebola virus
1. an RNA virus almost identical to the Marburg virus but serologically distinct; it causes a similar disease.
2. a virus of the genus Filovirus that is the etiologic agent of Ebola virus disease.
EEE virus eastern equine encephalomyelitis v.; see equine encephalomyelitis v.
encephalomyocarditis virus an enterovirus that causes mild aseptic meningitis and encephalomyocarditis.
enteric viruses an epidemiologic class of viruses that are normally acquired by ingestion and replicate in the intestinal tract, causing local rather than generalized infection.
enveloped virus a virus having an outer lipoprotein bilayer acquired by budding through the host cell membrane.
Epstein-Barr virus (EBV) human herpesvirus 4; a virus that causes infectious mononucleosis and is associated with Burkitt's lymphoma and nasopharyngeal carcinoma.
equine encephalomyelitis virus a group of arbovirus species of the genus Alphavirus that cause encephalomyelitis in horses, mules, and humans, transmitted by mosquitoes; there are three strains: eastern, western, and Venezuelan.
fixed virus one whose virulence and incubation period have been stabilized by serial passage and remained fixed during further transmission.
foamy viruses Spumavirus.
helper virus one that aids in the development of a defective virus by supplying or restoring the activity of the viral gene or enabling it to form a protein coat.
hepatitis virus the etiologic agent of viral hepatitis. Six types are recognized: hepatitis A virus, the agent causing infectious hepatitis, acquired by parenteral inoculation or by ingestion; hepatitis B virus, the agent causing serum hepatitis, transmitted by inadequately sterilized syringes and needles, or through infectious blood plasma, or certain blood products; hepatitis C virus, which causes hepatitis C; hepatitis D virus, a defective RNA viral agent that can replicate only in the presence of hepatitis B virus and is transmitted with it and causes hepatitis D; hepatitis E virus, a calicivirus transmitting hepatitis E; and hepatitis G virus, flavivirus isolated from patients with hepatitis but whose etiologic role is uncertain.
hepatitis B–like viruses Hepadnaviridae.
herpes virus herpesvirus.
herpes simplex virus (HSV) a virus of the genus Simplexvirus that is the etiologic agent of herpes simplex in humans. It is separable into two serotypes, designated 1 and 2 (called also human herpesvirus 1 and human herpesvirus 2 ); type 1 is transmitted by infected saliva and causes primarily nongenital lesions, and type 2 is sexually transmitted and causes primarily genital lesions.
human immunodeficiency virus (HIV) a human T-cell leukemia/lymphoma virus, of the genus Lentivirus, with a selective affinity for helper T cells that is the agent of the acquired immunodeficiency syndrome.
human T-cell leukemia virus human T-lymphotropic v.
human T-lymphotropic virus 1 (HTLV-1) a species of retroviruses of worldwide distribution, having an affinity for helper/inducer T lymphocytes; it causes chronic infection and is associated with adult T-cell leukemia and chronic progressive myelopathy.
human T-lymphotropic virus 2 (HTLV-2) a species of retroviruses having extensive serologic cross-reactivity with HTLV-1; no clear association with disease has been established.
igbo-ora virus an arbovirus of the genus Alphavirus that has been associated with a dengue-like disease in Nigeria, the Central African Republic, and the Ivory Coast.
influenza virus any of a group of orthomyxoviruses that cause influenza, including at least three genera: Influenzavirus A, Influenzavirus B, and Influenzavirus C. Serotype A viruses are subject to major antigenic changes (antigenic shifts) as well as minor gradual antigenic changes (antigenic drift) and cause the major pandemics.
influenza A virus , influenza B virus, influenza C virus species in the genera Influenzavirus A, Influenzavirus B, and Influenzavirus C; see influenza v.
Jamestown Canyon virus a virus of the genus Bunyavirus, serologically related to California encephalitis virus, that occasionally causes encephalitis.
JC virus (JCV) a polyomavirus that causes widespread infection in childhood and remains latent in the host; it is the cause of progressive multifocal leukoencepahalopathy.
La Crosse virus a virus of the California serogroup of the genus Bunyavirus, the etiologic agent of La Crosse encephalitis.
lymphocyte-associated virus any virus of the subfamily Gammaherpesviridae, members of which are specific for either B or T lymphocytes; infection is often arrested at a lytic or prelytic stage without production of infectious virions, and latent virus may frequently be demonstrated in lymphoid tissue.
lytic virus one that is replicated in the host cell and causes death and lysis of the cell.
Marburg virus an RNA virus occurring in Africa, transmitted by insect bite and causing Marburg disease.
masked virus a virus that ordinarily occurs in a noninfective state and is demonstrable by indirect methods which activate it, as by blind passage in experimental animals.
measles virus a paramyxovirus that is the cause of measles.
measles-like viruses Morbillivirus.
monkeypox virus an orthopoxvirus that produces mild exanthematous disease in monkeys and a smallpox-like disease in humans.
mumps virus a virus of the genus Rubulavirus that causes mumps and sometimes tenderness and swelling of the testes, pancreas, ovaries, or other organs.
naked virus , nonenveloped virus a virus lacking an outer lipoprotein bilayer.
neurotropic virus one that has a predilection for and causes infection in nervous tissues, e.g., the rabies virus.
Norwalk virus a calicivirus that is a common agent of epidemics of acute gastroenteritis.
oncogenic viruses an epidemiologic class of viruses that are acquired by close contact or injection and cause usually persistent infection; they may induce cell transformation and malignancy.
Oropouche virus a virus of the genus Bunyavirus that causes illness in Brazil; infection is characterized by fever, chills, malaise, headache, myalgia, and arthralgia, sometimes nausea and vomiting, and occasionally central nervous system involvement.
orphan viruses viruses isolated in tissue culture but not found specifically associated with any illness.
papilloma virus papillomavirus.
parainfluenza virus a group of viruses of the family Paramyxoviridae that cause upper respiratory tract disease in humans and other animals.
paravaccinia virus pseudocowpox v.
Powassan virus a tickborne virus of the genus Flavivirus that causes encephalitis in the eastern United States and Canada.
pox virus poxvirus.
pseudocowpox virus a virus of the genus Parapoxvirus that produces nodular lesions similar to those of cowpox and orf on the udders and teats of milk cows and the oral mucosa of suckling calves (paravaccinia), which can be transmitted to humans during milking.
Puumala virus see Hantavirus.
rabies virus an RNA virus of the rhabdovirus group that causes rabies.
rabies-like viruses Lyssavirus.
respiratory viruses an epidemiologic class of viruses that are acquired by inhalation of fomites and replicate in the respiratory tract, causing local rather than generalized infection; they are included in the families Adenoviridae, Coronaviridae, Orthomyxoviridae, Paramyxoviridae, and Picornaviridae.
respiratory syncytial viruses (RSV) viruses belonging to the genus Pneumovirus, causing respiratory disease that is particularly severe in infants, and in tissue causing syncytium formation.
RNA virus one whose genome consists of RNA.
Rous-associated virus (RAV) a helper virus in whose presence a defective Rous sarcoma virus is able to form a protein coat.
Rous sarcoma virus (RSV) see Rous sarcoma, under sarcoma .
rubella virus the sole species of the genus Rubivirus, the etiologic agent of rubella.
St. Louis encephalitis virus a virus of the genus Flavivirus, that is the etiologic agent of St. Louis encephalitis; transmitted by mosquitoes.
sandfly fever viruses Phlebovirus.
satellite virus a strain of virus unable to replicate except in the presence of helper virus; considered to be deficient in coding for capsid formation.
Seoul virus see Hantavirus.
simian immunodeficiency virus (SIV) a virus of the genus Lentivirus, closely related to human immunodeficiency virus, that causes inapparent infection in African green monkeys and a disease resembling acquired immunodeficiency syndrome in macaques.
Sin Nombre virus a virus of the genus Hantavirus that causes hantavirus pulmonary syndrome in the western United States.
slow virus any virus causing a disease characterized by a long preclinical course and gradual progression once the symptoms appear.
street virus virus from a naturally infected animal, as opposed to a laboratory-adapted strain of the virus.
tanapox virus a virus of the genus Yatapoxvirus that is the etiologic agent of tanapox.
Toscana virus a virus of the Naples serogroup of the genus Phlebovirus, an etiologic agent of phlebotomus fever.
varicella-zoster virus human herpesvirus 3
variola virus the virtually extinct virus, belonging to the genus Orthopoxvirus, that is the etiologic agent of smallpox. No natural infection has occurred since 1977 and no reservoir of the virus now exists.
VEE virus , Venezuelan equine encephalomyelitis virus see equine encephalomyelitis v.
WEE virus , western equine encephalomyelitis virus see equine encephalomyelitis v.
West Nile virus a virus of the genus Flavivirus that causes West Nile encephalitis; it is transmitted by Culex mosquitoes, with wild birds serving as the reservoir.
Yaba monkey tumor virus a virus of the genus Yatapoxvirus that is the etiologic agent of yabapox.
yellow fever virus a mosquito-borne species of the genus Flavivirus that causes yellow fever in Central and South America and Africa.
vi·rus (v  r s)n. pl. vi·rus·es 1. Any of a large group of submicroscopic agents that act as parasites and consist of a segment of DNA or RNA surrounded by a coat of protein. Because viruses are unable to replicate without a host cell, they are not considered living organisms in conventional taxonomic systems. Nonetheless, they are described as "live" when they are capable of replicating and causing disease. 2. A disease caused by a virus. |
Virus
A tiny particle that can cause infections by duplicating itself inside a cell using the cell's own software. Antibiotics are ineffective against viruses, though antiviral drugs exist for some viruses, including chickenpox.
Mentioned in: Adenovirus Infections, Antiretroviral Drugs, Antiviral Drugs, Birth Defects, Chickenpox, Encephalitis, Tropical Spastic Paraparesis, Vaginal Pain
virus
[vī′rəs]
Etymology: L, poison
a minute parasitic microorganism much smaller than a bacterium that, having no independent metabolic activity, may replicate only within a cell of a living plant or animal host. A virus consists of a core of nucleic acid (deoxyribonucleic acid or ribonucleic acid) surrounded by a coat of antigenic protein, sometimes surrounded by an envelope of lipoprotein. The virus provides the genetic code for replication, and the host cell provides the necessary energy and raw materials. More than 200 viruses have been identified as capable of causing disease in humans. Some types of viruses are adenovirus, arenavirus, enterovirus, herpesvirus, and rhinovirus. See also viral infection. viral, adj.
virus,
n the smallest living microscopic organism. Comprises nucleic acid and enclosed by a layer of protein. It only reproduces within another living organism, and viruses are responsible for a number of diseases including the common cold, influenza, and AIDS.
)
Virus.
virus (vī´rus),
n one of a group of heterogeneous infective agents characterized by the lack of independent metabolism or the ability to replicate outside the host cell.
virus, herpes simplex,
n See herpes simplex.
virus replication,
n the ability of viruses to reproduce within a host cell.
virus
any member of a unique class of infectious agents, which were originally distinguished by their smallness (hence, they were described as 'filtrable' because of their ability to pass through bacteria-retaining filters) and their inability to replicate outside of a living host cell; because these properties are shared by certain bacteria (rickettsiae, chlamydiae), viruses are further characterized by their simple organization and their unique mode of replication. A virus consists of genetic material, which may be either DNA or RNA, and is surrounded by a protein coat and, in some viruses, by a membranous envelope.
For a list of animal viruses and their classification see Table 8.1.
Unlike cellular organisms, viruses do not contain all the biochemical mechanisms for their own replication; viruses replicate by using the biochemical mechanisms of a host cell to synthesize and assemble their separate components. When a complete virus particle (virion) comes in contact with a host cell, the viral nucleic acid and, in some viruses, a few enzymes are introduced into the host cell.
Viruses vary in their stability; some such as poxviruses, parvoviruses and rotaviruses are very stable and survive well outside the body while others, particularly those viruses that are enveloped, such as herpesvirus, influenza virus, do not survive well and therefore usually require close contact for transmission and are readily destroyed by disinfectants, particularly those with a detergent action. Some viruses produce acute disease while others, sometimes referred to as slow viruses, such as retroviruses and lentiviruses and the scrapie agent, produce diseases which progress often to death over many years. Viruses in several families are transmitted by arthropod vectors.
virus amplification
see replication.
arbor virus
an incorrect, obsolete term for arbovirus.
attenuated virus
one whose pathogenicity has been reduced by serial animal passage or other means. See also attenuation (2).
avianized virus
see avianized.
bacterial virus
one that is capable of producing transmissible lysis of bacteria. See also bacteriophage.
C-type virus
see c-type virus.
Coxsackie virus
coxsackievirus.
defective virus
one that cannot be completely replicated or cannot form a protein coat or envelope; in some cases replication can proceed if missing gene functions are supplied by other viruses, termed helper virus (see below).
ECHO virus
see echovirus.
enteric virus
see enterovirus.
enteric orphan v's
orphan viruses isolated from the intestinal tract but not known to cause disease, hence orphan.
feline sarcoma virus
see feline sarcoma virus.
filterable virus, filtrable virus
a pathogenic agent capable of passing through fine filters able to exclude bacteria; outdated terminology.
fixed virus, virus fixé
rabies virus whose virulence and incubation period have been stabilized by serial passage and have remained fixed during further transmission; used for inoculating animals from which rabies vaccine is prepared.
foaming virus
feline syncytia-forming virus (FeSFV). So called because it causes foamy degeneration in feline cell cultures.
helper virus
one that aids in the development of a defective virus by supplying or restoring the activity of the viral gene such as that forming the protein coat.
herpes virus
herpesvirus.
human hepatitis virus
infection of chimpanzees with some of the human hepatitis viruses can result in infection of human workers.
influenza virus
any of a group of orthomyxoviruses that causes influenza. See influenza.
latent virus
a noninfective state and is demonstrable by indirect methods that activate it.
lytic virus
one that is replicated in the host cell and causes death and lysis of the cell.
masked virus
latent virus.
virus N
a type A influenza virus found in birds.
virus neutralization
see neutralization tests.
occult virus
see occult virus.
orphan virus
see orphan virus.
parainfluenza virus
see parainfluenzavirus.
pox virus
see pox.
rabies virus
an RNA virus of the rhabdovirus group that causes rabies.
respiratory syncytial virus
see paramyxoviridae.
slow virus
the name given to certain viruses that cause diseases characterized by a long incubation period and a very prolonged clinical course, e.g. the lentiviruses of sheep, maedi and visna.
street virus
rabies virus from a naturally infected animal, as opposed to a laboratory-adapted, fixed virus.
virus
A submicroscopic (20-600 nm in diameter) particle (called a virion), which typically contains a protein coat (called a capsid) surrounding genetic material in the form of a double or a single strand of RNA or DNA. Viruses replicate only within cells of living hosts. They can infect cells and are the cause of various diseases. This is accomplished by releasing the viral genetic material into the host cytoplasm if it is RNA, and into the host nucleus if it is DNA, and thus inducing the production of new viral particles and newly infected cells. There are many viruses: DNA viruses as for example the adenovirus (some of which can cause epidemic conjunctivitis), herpesvirus and pox viruses, and RNA viruses as for example the picorna virus (e.g. hepatitis A), toga viruses (e.g. rubella), corona viruses (which can cause respiratory infection) and the retroviruses (e.g. HIV). See antiviral agents; herpesvirus; gene therapy.
virus
Infectious disease A small, obligatorily intracellular agent ranging from 106 daltons–eg, Parvoviridae to 200 x 106–eg, Poxviridae; viral nucleic acid is single- or double-stranded, either DNA or RNA,
and is a closed circle or opened and linear; viral nucleic acid is packaged within a protein coat–capsid composed of a few distinct types of protein; most have a helical or icosahedral symmetry; once inside the infected cell, the virus uses
the host's synthetic capabilities to produce progeny virus; some viruses–eg, influenza virus, are 'studded' with external proteins–eg, hemagglutinins, neuraminidases
Patient discussion about Toscana virus.
Q. Should I Vaccinate My Daughter Against HPV? I have a 12 year old daughter. Her School wants all the girls aged 12 and up to be vaccinated against HPV. A lot of Parents are against this vaccine. I want to know more about this vaccine and if I should vaccinate my daughter.
A. I found this video which discusses this issue:
http://www.5min.com/Video/Should-I-Vaccinate-My-Daughter-Against-HPV-7272
http://www.5min.com/Video/Should-I-Vaccinate-My-Daughter-Against-HPV-7272
Q. Is there a connection between Epstein-Barr Virus and Fibromyalgia and where can I find information? I was diagnosed with EBV 10 years ago and got diagnosed with Fibromyalgia and Depression 5 yrs ago-is there a connection and if so where can I obtain information. If anyone can help-Thank You!
A. EBV is a herpes virus. And there are arguments from both sides if it has a connection or not to Fibromyalgia, some articles say that , some say the other. The truth is that for the patient it doesn’t mater. If you have it you have to deal with it and it doesn’t mater how it showed up. This mater to the researches.
Q. can an HIV virus last when it comes in contact with air and out of the body? in what ways can i get HIV? and what are the treatment options ? is it treatable ? and what are the side effects for this kind of treatment ?
A. This virus may be passed from one person to another when infected blood, semen, or vaginal secretions come in contact with an uninfected person’s broken skin or mucous membranes*. In addition, infected pregnant women can pass HIV to their baby during pregnancy or delivery, as well as through breast-feeding. People with HIV have what is called HIV infection. Some of these people will develop AIDS as a result of their HIV infection. http://www.cdc.gov/hiv/resources/qa/qa1.htm
http://en.wikipedia.org/wiki/HIV Hope this helps.
Read more or ask a question about Toscana virushttp://en.wikipedia.org/wiki/HIV Hope this helps.
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|