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Passenger Virus
A passenger virus is a virus that is frequently found in samples from diseased tissue, such as tumours, but is not a contributing factor in causing the disease. Experimental demonstration of passenger status Proving that a virus has no causative role can be difficult. Although none of the following signs is definitive, evidence that a virus found in diseased tissue might be passenger only rather than a causative agent includes: *injection of the virus into healthy animals without causing disease; *the absence of the virus at the earliest stages of the disease; *curing the viral infection using antiviral drugs or vaccination with no effect on the course of the disease. Examples A well-established example is lactate dehydrogenase virus, which is often found in mouse tumours. GB virus C and Chandipura virus are possible examples in humans. It has also been suggested that a virus related to Alcelaphine herpesvirus 1 is a passenger virus that, unlike AHV1 itself, does not cause bovine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumour
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists in growing abnormally, even if the original trigger is removed. This abnormal growth usually forms a mass, when it may be called a tumor. ICD-10 classifies neoplasms into four main groups: benign neoplasms, in situ neoplasms, malignant neoplasms, and neoplasms of uncertain or unknown behavior. Malignant neoplasms are also simply known as cancers and are the focus of oncology. Prior to the abnormal growth of tissue, as neoplasia, cells often undergo an abnormal pattern of growth, such as metaplasia or dysplasia. However, metaplasia or dysplasia does not always progress to neoplasia and can occur in other conditions as well. The word is from Ancient Greek 'new' and 'formation, creation'. Types A neoplasm can be benign, potentially ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies and autoimmune disorders. In humans, ''disease'' is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person affected, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiviral Drug
Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do not destroy their target pathogen; instead they inhibit its development. Antiviral drugs are one class of antimicrobials, a larger group which also includes antibiotic (also termed antibacterial), antifungal and antiparasitic drugs, or antiviral drugs based on monoclonal antibodies. Most antivirals are considered relatively harmless to the host, and therefore can be used to treat infections. They should be distinguished from viricides, which are not medication but deactivate or destroy virus particles, either inside or outside the body. Natural viricides are produced by some plants such as eucalyptus and Australian tea trees. Medical uses Most of the antiviral drugs now available are designed to help deal with HIV, herpes viruses, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaccination
Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating the body's adaptive immunity, they help prevent sickness from an infectious disease. When a sufficiently large percentage of a population has been vaccinated, herd immunity results. Herd immunity protects those who may be immunocompromised and cannot get a vaccine because even a weakened version would harm them. The effectiveness of vaccination has been widely studied and verified. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio and tetanus from much of the world. However, some diseases, such as measles outbreaks in America, have seen rising cases due to relative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactate Dehydrogenase Elevating Virus
Lactate dehydrogenase elevating virus (LDV) constitutes the species ''Gamamaarterivirus lacdeh'' which is part of the family ''Arteriviridae'' and order '' Nidovirales''. The order ''Nidovirales'' also includes the family of coronaviruses. Arteriviruses infect macrophages in animals and cause a variety of diseases. LDV specifically causes lifelong persistent viremia in mice, but does not harm the host and only slightly harms the immune system. The main clinical sign is an increased level of the plasma enzyme lactate dehydrogenase (LDH). LDV has a remarkably narrow cell type specificity, meaning nothing homologous with LDV in mice has been found in another species. Discovery LDV was discovered in 1960 by Dr. Vernon Riley and his colleagues while they were working with plasma enzymes in tumor-bearing mice. They found that many types of transplantable tumors caused a five to tenfold increase in the plasma lactate dehydrogenase (LDH) activity within three days of the transplantation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GB Virus C
GB virus C (GBV-C), formerly known as hepatitis G virus (HGV) and also known as human pegivirus – HPgV is a virus in the family ''Flaviviridae'' and a member of the ''Pegivirus'', is known to infect humans, but is not known to cause human disease. Reportedly, HIV patients coinfected with GBV-C can survive longer than those without GBV-C, but the patients may be different in other ways. Research is active into the virus' effects on the immune system in patients coinfected with GBV-C and HIV. Human infection The majority of immunocompetent individuals clear GBV-C viraemia, but in some individuals, infection persists for decades. However, the time interval between GBV-C infection and clearance of viraemia (detection of GBV-C RNA in plasma) is not known. About 2% of healthy US blood donors are viraemic with GBV-C, and up to 13% of blood donors have antibodies to E2 protein, indicating possible prior infection. Parenteral, sexual, and vertical transmissions of GBV-C have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chandipura Virus
''Chandipura vesiculovirus'' (CHPV) is a member of the ''Rhabdoviridae'' family that is associated with an encephalitic illness in humans. It was first identified in 1965 after isolation from the blood of two patients from Chandipura village in Maharashtra state, India and has been associated with a number of otherwise unexplained outbreaks of encephalitic illness in central India. The most recent occurred in Andhra Pradesh and Maharashtra in June–August 2003 with 329 children affected and 183 deaths. Further sporadic cases and deaths in children were observed in Gujarat state in 2004. ''Chandipura vesiculovirus'' has been isolated from sandflies in India and West Africa and is probably spread through its bite. The presence of the virus in Africa indicates a wide distribution although no human cases have been observed outside India. The significance of ''Chandipura vesiculovirus'' as a human pathogen is unresolved due to doubts over its role in the 2003 and 2004 outbreaks. _ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcelaphine Herpesvirus 1
The subfamily Alcelaphinae or tribe Alcelaphini of the family Bovidae contains wildebeest, hartebeest, bonteboks, and several similar species. Depending on the classification, there are 6–10 species placed in four genera, although ''Beatragus'' is sometimes considered a subgenus of ''Damaliscus'', and ''Sigmoceros'' for the Lichtenstein's hartebeest. Subfamily Alcelaphinae * Genus ''Beatragus'' ** Hirola, ''Beatragus hunteri'' * Genus ''Damaliscus'' ** Tsessebe, ''D. lunatus'' *** Korrigum, ''D. lunatus korrigum'' *** Topi, ''D. lunatus jimela'' *** Coastal topi, ''D. lunatus topi'' ** Bontebok, ''D. pygargus'' *** Bontebok (subspecies), ''D. p. pygargus'' *** Blesbok, ''D. p. phillipsi'' * Genus '' Alcelaphus'' ** Hartebeest, ''A. buselaphus'' *** Bubal hartebeest, †''A. b. buselaphus'' *** Coke's hartebeest, ''A. b. cokii'' *** Lelwel hartebeest, ''A. b. lelwel'' *** Western hartebeest, ''A. b. major'' *** Swayne's hartebeest, ''A. b. swaynei'' *** Tora hartebeest, ''A. b. t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bovine Malignant Catarrhal Fever
Bovine malignant catarrhal fever (BMCF) is a fatal lymphoproliferative disease caused by a group of ruminant gamma herpes viruses including ''Alcelaphine gammaherpesvirus 1'' (AlHV-1) and ''Ovine gammaherpesvirus 2'' (OvHV-2) These viruses cause unapparent infection in their reservoir hosts (sheep with OvHV-2 and wildebeest with AlHV-1), but are usually fatal in cattle and other ungulates such as deer, antelope, and buffalo. In Southern Africa the disease is known as ''snotsiekte'', from the Afrikaans. BMCF is an important disease where reservoir and susceptible animals mix. There is a particular problem with Bali cattle in Indonesia, bison in the US and in pastoralist herds in Eastern and Southern Africa. Disease outbreaks in cattle are usually sporadic although infection of up to 40% of a herd has been reported. The reasons for this are unknown. Some species appear to be particularly susceptible, for example Pére David's deer, Bali cattle and bison, with many deer dying with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duesberg Hypothesis
The Duesberg hypothesis is the claim that AIDS is not caused by HIV, but, instead, that AIDS is caused by noninfectious factors such as recreational and pharmaceutical drug use and that HIV is merely a harmless passenger virus. The hypothesis was popularized by University of California, Berkeley professor Peter Duesberg, from whom the hypothesis gets its name. The scientific consensus is that the Duesberg hypothesis is incorrect and that HIV is the cause of AIDS. The most prominent supporters of the hypothesis are Duesberg himself, biochemist and vitamin proponent David Rasnick and journalist Celia Farber. The scientific community generally contends that Duesberg's arguments in favor of the hypothesis are the result of cherry-picking predominantly outdated scientific data and selectively ignoring evidence that demonstrates HIV's role in causing AIDS. Role of legal and illegal drug use Duesberg argues that there is a statistical correlation between trends in recreational drug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etiology
Etiology (pronounced ; alternatively: aetiology or ætiology) is the study of causation or origination. The word is derived from the Greek (''aitiología'') "giving a reason for" (, ''aitía'', "cause"); and ('' -logía''). More completely, etiology is the study of the causes, origins, or reasons behind the way that things are, or the way they function, or it can refer to the causes themselves. The word is commonly used in medicine (pertaining to causes of disease) and in philosophy, but also in physics, psychology, government, geography, spatial analysis, theology, and biology, in reference to the causes or origins of various phenomena. In the past, when many physical phenomena were not well understood or when histories were not recorded, myths often arose to provide etiologies. Thus, an etiological myth, or origin myth, is a myth that has arisen, been told over time or written to explain the origins of various social or natural phenomena. For example, Virgil's ''Aeneid'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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