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  • pathogenic viruses
  • While the scientific literature indicates that over 5,500 phages have been described Ackermann (Arch Virol 152(2):227-243, 2007), much of the scientific community has focused attention on the relatively fewer pathogenic viruses of humans, animals, and agricultural crops. (springer.com)
  • Since then, other pathogenic viruses that are responsible for gastroenteritis, hepatitis, and many other virus strains have replaced enteroviruses as the main aim for detection in the water environment. (wikipedia.org)
  • virions
  • Following late gene synthesis, which includes proteins that are important for replicating and encasing the virus, progeny virions are then released by the infected cell to invade other cells so that the process can be repeated. (encyclopedia.com)
  • As the infected cancer cells are destroyed by oncolysis, they release new infectious virus particles or virions to help destroy the remaining tumour. (wikipedia.org)
  • biological
  • First seen as poisons, then as life-forms, then biological chemicals, viruses today are thought of as being in a gray area between living and nonliving: they cannot replicate on their own but can do so in truly living cells and can also affect the behavior of their hosts profoundly. (scientificamerican.com)
  • The categorization of viruses as nonliving during much of the modern era of biological science has had an unintended consequence: it has led most researchers to ignore viruses in the study of evolution. (scientificamerican.com)
  • Because they were clearly biological themselves and could be spread from one victim to another with obvious biological effects, viruses were then thought to be the simplest of all living, gene-bearing life-forms. (scientificamerican.com)
  • It is now well-established that viruses are the most abundant biological entities on Earth and are estimated to harbor the second greatest biomass after prokaryotes, equivalent to the amount of carbon found in ~75 million blue whales (the largest organism on Earth) Suttle (Nature 437(7057):356-361, 2005). (springer.com)
  • A virus is a biological agent that reproduces inside the cells of living hosts. (wikipedia.org)
  • Viruses are found in almost every ecosystem on Earth and are the most abundant type of biological entity. (wikipedia.org)
  • This is a list of genera of biological viruses. (wikipedia.org)
  • Zika
  • Zika virus evolution and spread in the Americas. (nih.gov)
  • Although the recent Zika virus (ZIKV) epidemic in the Americas and its link to birth defects have attracted a great deal of attention, much remains unknown about ZIKV disease epidemiology and ZIKV evolution, in part owing to a lack of genomic data. (nih.gov)
  • This episode of Infectious Questions responds to questions raised in media reports that pesticides, rather than the Zika Virus, might be responsible for such birth defects as microcephaly. (libsyn.com)
  • I convened an Emergency Committee, under the International Health Regulations, to gather advice on the severity of the health threat associated with the continuing spread of Zika virus disease in Latin America and the Caribbean. (who.int)
  • The Committee found no public health justification for restrictions on travel or trade to prevent the spread of Zika virus. (who.int)
  • proteins
  • Interestingly, even though biologists long favored the view that viruses were mere boxes of chemicals, they took advantage of viral activity in host cells to determine how nucleic acids code for proteins: indeed, modern molecular biology rests on a foundation of information gained through viruses. (scientificamerican.com)
  • These "early" proteins are also important for promoting "late" viral gene synthesis and preparing the cell for the production of progeny virus. (encyclopedia.com)
  • The pathogenicity of HPIVs is mutually dependent on the viruses having the correct accessory proteins which are able to elicit anti-interferon properties. (wikipedia.org)
  • The main mechanisms involve expressing proteins which coat the virus and interact with the structure of the plasmodesmata. (wikipedia.org)
  • The array of proteins expressed by the different viruses may act differently but all achieve a similar goal, passage between adjacent cells. (wikipedia.org)
  • The Lassa virus gains entry into the host cell by means of the cell-surface receptor the alpha-dystroglycan (alpha-DG), a versatile receptor for proteins of the extracellular matrix. (wikipedia.org)
  • humans
  • There are six different DNA virus families that infect and may cause significant disease in humans. (encyclopedia.com)
  • Some viruses of animals, including humans, are spread by exposure to infected bodily fluids. (wikipedia.org)
  • Epidemics caused by viruses began when human behaviour changed during the Neolithic period, around 12,000 years ago, when humans developed more densely populated agricultural communities. (wikipedia.org)
  • Viruses of plants and livestock also increased, and as humans became dependent on agriculture and farming, diseases such as potyviruses of potatoes and rinderpest of cattle had devastating consequences. (wikipedia.org)
  • Having evolved from viruses that infected other animals, they first appeared in humans in Europe and North Africa thousands of years ago. (wikipedia.org)
  • Over the past 50,000-100,000 years, as modern humans increased in numbers and dispersed throughout the world, new infectious diseases emerged, including those caused by viruses. (wikipedia.org)
  • The virus, which only infected humans, probably descended from the poxviruses of rodents. (wikipedia.org)
  • Humans probably came into contact with these rodents, and some people became infected by the viruses they carried. (wikipedia.org)
  • Herpes viruses first infected the ancestors of modern humans over 80 million years ago. (wikipedia.org)
  • Lassa virus (LASV) is an arenavirus that causes Lassa hemorrhagic fever, a type of viral hemorrhagic fever (VHF), in humans and other primates. (wikipedia.org)
  • capsid
  • 2004. The structure of a thermophilic archaeal virus shows a double-stranded DNA viral capsid type that spans all domains of life. (tolweb.org)
  • In the case of some DNA viruses, the capsid can be surrounded by a membrane that is formed from cellular membranes. (encyclopedia.com)
  • You can then cut/paste the capsid gene into an 'alive' virus in place of its own capsid, and voila! (scienceblogs.com)
  • The rate of protein, nucleic acid denaturation and chemical reactions that destroy the viral capsid are increased at higher temperatures, thus viruses will survive best at low temperatures. (wikipedia.org)
  • A distinguishing feature of the dsRNA viruses, irrespective of their family association, is their ability to carry out transcription of the dsRNA segments, under appropriate conditions, within the capsid. (wikipedia.org)
  • herpes simplex vi
  • Pseudotumour of the tongue caused by herpes simplex virus type 2 in an HIV-1 infected immunosuppressed patient. (springer.com)
  • The herpes simplex virus type 1 (HSV-1) mutant 1716 lacks both copies of the ICP34.5 gene, and as a result is no longer able to replicate in terminally differentiated and non-dividing cells but will infect and cause lysis very efficiently in cancer cells, and this has proved to be an effective tumour-targeting strategy. (wikipedia.org)
  • whereas
  • The mobility of animals increases the mechanisms of viral transmission that have evolved, whereas plants remain immobile and thus plant viruses must rely on environmental factors to be transmitted between hosts. (wikipedia.org)
  • The English plural is viruses (sometimes also viri or vira), whereas the Latin word is a mass noun, which has no classically attested plural (Neo-Latin had vīra is used). (wikipedia.org)
  • genera
  • The orthoreoviruses (reoviruses) are the prototypic members of the virus Reoviridae family and representative of the turreted members, which comprise about half the genera. (wikipedia.org)
  • polio virus
  • Some viruses could not be grown in chickens' eggs, but this problem was solved in 1949 when John Franklin Enders, Thomas Huckle Weller and Frederick Chapman Robbins grew polio virus in cultures of living animal cells. (wikipedia.org)
  • infectious
  • A virus is a small infectious agent that replicates only inside the living cells of other organisms. (wikipedia.org)
  • A meaning of "agent that causes infectious disease" is first recorded in 1728, before the discovery of viruses by Dmitri Ivanovsky in 1892. (wikipedia.org)
  • particles
  • While not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles. (wikipedia.org)
  • ICTV
  • Though not used by the ICTV, Baltimore classification, which groups viruses together based on how they produce mRNA, is used in conjunction with the ICTV's work in modern virus classification. (wikipedia.org)
  • Developments in plant virus taxonomy since the publication of the 6th ICTV Report. (wikipedia.org)
  • hosts
  • The hosts for a virus are system-call interfaces that are accessible from the point of entry (an infected program), such as sendmail or an HTTP server. (qnx.com)
  • The hosts are platform-specific, so a virus for Linux would in all likelihood terminate the host under QNX Neutrino as soon as it tried to do anything damaging. (qnx.com)
  • Since viruses are obligate intracellular parasites they must develop direct methods of transmission, between hosts, in order to survive. (wikipedia.org)
  • Nevertheless, the rigidity of the cell wall of plant cells, not only poses a problem for transmission of the viruses between different plant hosts, but also acts to prevent viral transmission between cells. (wikipedia.org)
  • antiviral
  • Antibiotics have no effect on viruses, but antiviral drugs have been developed to treat life-threatening infections. (wikipedia.org)
  • In recent years the increasing knowledge of virus particle assembly, virus-cell interactions, and viral pathogenesis allow approaches for the development of novel antiviral strategies or agents. (wikipedia.org)
  • Antibiotics have no effect on viruses, but several antiviral drugs have been developed. (wikipedia.org)
  • replicate
  • Each time a host file is run, the virus code in it will replicate - that is, it will create and insert more unwanted code, either into the same file or into another file on the same machine (essentially infecting the other file as well). (f-secure.com)
  • Like all viruses, DNA viruses are small when compared to the cells they infect and as such are obligate intracellular parasites (parasites that can only replicate within cells). (encyclopedia.com)
  • Most of the viruses in this family also replicate in both the nucleus and cytoplasm, thus the name nucleocytoplasmic. (wikipedia.org)
  • Adenoviruses
  • Hepatitis A, adenoviruses and parvoviruses have the highest survival rate in low temperatures amongst enteric viruses. (wikipedia.org)
  • Double stranded DNA viruses like adenoviruses are more resistant to UV light inactivation than enteroviruses because they can use their host cell to repair the damage caused by the UV light. (wikipedia.org)
  • clades
  • The taxonomic division is broadly based on antigenic and genetic characteristics, forming four major serotypes or clades, which today are considered distinct viruses. (wikipedia.org)
  • The megaviridae virus can be found infecting acanthamoeba or other protozoan clades. (wikipedia.org)
  • In contrast, the New World arenaviruses of clades A and B, which include the important viruses Machupo, Guanarito, Junin, and Sabia in addition to the non pathogenic Amapari virus, use the transferrin receptor 1. (wikipedia.org)
  • scientists
  • Finally, however, scientists are beginning to appreciate viruses as fundamental players in the history of life. (scientificamerican.com)
  • Scientists find the first indications that there may be healthy viruses living in your gut. (newsweek.com)
  • At the same time several other scientists proved that, although these agents (later called viruses) were different from bacteria, they could still cause disease, and they were about one hundredth the size of bacteria. (wikipedia.org)
  • A problem for early scientists was that they did not know how to grow viruses without using live animals. (wikipedia.org)
  • dependent
  • Unlike most enveloped viruses which use clathrin coated pits for cellular entry and bind to their receptors in a pH dependent fashion, Lassa and lymphocytic choriomeningitis virus instead use an endocytotic pathway independent of clathrin, caveolin, dynamin and actin. (wikipedia.org)
  • typically
  • Typically, mobile devices are difficult for virus writers to target, since their simplicity provides fewer security holes to target compared to a desktop. (wikipedia.org)
  • Many cases of hepatitis A and/or E, both of which are enteric viruses, are typically transmitted by food and water. (wikipedia.org)
  • norovirus
  • Viruses such as norovirus are transmitted by the faecal-oral route, which involves the contamination of hands, food and water. (wikipedia.org)
  • plant
  • Viruses are known to infect both plant cells and animal cells. (wikipedia.org)
  • The structural differences between plant and animal cells have resulted in a variety of transmission routes being exploited, enabling the virus to be passed between different host plants. (wikipedia.org)
  • Consequently the virus must modify the plasmodesmata as they, themselves, are too large to fit through the small and tightly regulated plant structure. (wikipedia.org)
  • They may have common ancestry with plant positive strand RNA viruses in supergroup 1 with potyvirus lineages, respectively A new clade (as yet unnamed) of six viruses infecting filamentous fungi has been reported. (wikipedia.org)
  • Experiments
  • There are ERV families- take all the ones that are related and still have a gag or a env , figure out what their common ancestor looks like, and then do experiments with the resulting protein mashed together with a virus we know how to work with (pseudoviruses/dummy viruses). (scienceblogs.com)
  • Genus
  • The cytoplasmic polyhedrosis viruses (CPVs) form the genus Cypovirus of the family Reoviridae. (wikipedia.org)
  • It is a double-stranded RNA non-enveloped virus The members of genus Orbivirus within the Reoviridae family are arthropod borne viruses and are responsible for high morbidity and mortality in ruminants. (wikipedia.org)
  • organisms
  • Viruses affect all living organisms from single cellular plants, bacteria and animal to the highest forms of plants and animals including human beings. (wikipedia.org)
  • Because they possess some but not all such qualities, viruses have been described as "organisms at the edge of life", and as replicators. (wikipedia.org)
  • host
  • Once integrated, the virus may become latent , allowing the virus and its host cell to avoid detection by the immune system, for an indiscriminate amount of time. (wikipedia.org)
  • More poetically, virologists Marc H. V. van Regenmortel of the University of Strasbourg in France and Brian W. J. Mahy of the Centers for Disease Control and Prevention have recently said that with their dependence on host cells, viruses lead "a kind of borrowed life. (scientificamerican.com)
  • This video also discusses virus structures and why a host is critical for viral reproduction. (youtube.com)
  • Atanasova NS, Roine E, Oren A, Bamford DH, Oksanen HM (2012) Global network of specific virus-host interactions in hypersaline environments. (springer.com)
  • Viruses need an entry point and a host. (qnx.com)
  • Most Unix-style systems aren't susceptible to viruses since the ability to do (much) damage is limited by the host. (qnx.com)
  • A computer virus is a harmful program that is designed to insert unwanted code into another program or file (the host file). (f-secure.com)
  • Each time the host file is run, the virus code in it will also run and insert more unwanted code, either into the same file or into other files on the same machine. (f-secure.com)
  • If it happens often enough, the virus code can completely corrupt the host file. (f-secure.com)
  • In addition to infecting its host files, a virus can often perform other harmful actions on the affected computer. (f-secure.com)
  • When infected by a virus, a host cell is forced to produce thousands of identical copies of the original virus at an extraordinary rate. (wikipedia.org)
  • new viruses are assembled in the infected host cell. (wikipedia.org)
  • and in some viruses, an envelope of fat that surrounds the protein coat and is used, in combination with specific receptors, to enter a new host cell. (wikipedia.org)
  • However, they are usually eliminated by the immune system, conferring lifetime immunity to the host for that virus. (wikipedia.org)
  • The virus commonly uses these methods to be passed from one host to another. (wikipedia.org)
  • Oncolytic viruses are thought not only to cause direct destruction of the tumour cells, but also to stimulate host anti-tumour immune responses. (wikipedia.org)
  • gastroenteritis
  • Members of this group include the rotaviruses, known globally as a common cause of gastroenteritis in young children, and bluetongue virus, an economically important pathogen of cattle and sheep. (wikipedia.org)
  • immune
  • NIAID is exploring therapies that suppress the amount of HIV to such low levels that an HIV-infected person would no longer need treatment because his or her immune system could keep the remaining virus in check, creating in essence a "functional cure. (nih.gov)
  • Viral infections in animals provoke an immune response that usually eliminates the infecting virus. (wikipedia.org)
  • Some viruses including those that cause AIDS and viral hepatitis evade these immune responses and result in chronic infections. (wikipedia.org)
  • the very frequent development of an immune response, while harmless to the patient, destroyed the virus and thus prevented it from destroying the cancer. (wikipedia.org)
  • origins
  • 2000. The origins and ongoing evolution of viruses. (tolweb.org)
  • The origins of viruses are unclear: some may have evolved from plasmids-pieces of DNA that can move between cells-while others may have evolved from bacteria. (wikipedia.org)
  • 2000
  • 2000. Virus Taxonomy. (tolweb.org)
  • 2000. Virus nomenclature: consensus versus chaos. (tolweb.org)
  • Baranyi U, Klein R, Lubitz W, Kruger DH, Witte A (2000) The archaeal halophilic virus-encoded Dam-like methyltransferase M. phiCh1-I methylates adenine residues and complements dam mutants in the low salt environment of Escherichia coli. (springer.com)
  • cells
  • The newly created viral bits assemble and, voilà, more virus arises, which also may infect other cells. (scientificamerican.com)
  • This myopic view allows them to see only how viruses co-opt cells or cause disease. (scientificamerican.com)
  • There are a variety of methods the virus can use to spread throughout the organism but the most common route use the vascular system, otherwise known as the xylem and phloem, and the plasmodesmata, which interconnect adjacent cells. (wikipedia.org)
  • Herpes simplex virus (HSV) was one of the first viruses to be adapted to attack cancer cells selectively, because it was well understood, easy to manipulate and relatively harmless in its natural state (merely causing cold sores) so likely to pose fewer risks. (wikipedia.org)
  • structures
  • This exposure to multiple complex chemical structures that carry out the processes of life is probably a reason that most molecular biologists do not spend a lot of time puzzling over whether viruses are alive. (scientificamerican.com)
  • feces
  • By 1972, the multimammate rat was found to be the main reservoir of the virus in West Africa, able to shed virus in its urine and feces without exhibiting visible symptoms. (wikipedia.org)
  • 20th century
  • In the early 20th century the English bacteriologist Frederick Twort discovered viruses that infect bacteria, and the French-Canadian microbiologist Félix d'Herelle described viruses that, when added to bacteria growing on agar, would lead to the formation of whole areas of dead bacteria. (wikipedia.org)
  • In the 20th century many diseases both old and new were found to be caused by viruses. (wikipedia.org)
  • tobacco mosai
  • Their demotion to inert chemicals came after 1935, when Wendell M. Stanley and his colleagues, at what is now the Rockefeller University in New York City, crystallized a virus- tobacco mosaic virus-for the fi rst time. (scientificamerican.com)
  • In the early 1890s the Russian biologist Dmitri Ivanovsky used this filter to study what became known as the tobacco mosaic virus. (wikipedia.org)
  • In 1935 American biochemist and virologist Wendell Meredith Stanley examined the tobacco mosaic virus and found it to be mostly made from protein. (wikipedia.org)
  • cause
  • during this period the virus does not cause symptoms. (wikipedia.org)
  • Once a person catches Epstein Barr virus, it is believed that the virus remains in his or her body for life, though it usually does not cause further illness. (sa.gov.au)
  • Human parainfluenza viruses (HPIVs) are the viruses that cause human parainfluenza. (wikipedia.org)
  • HPIVs remain the second main cause of hospitalisation in children under 5 years of age suffering from a respiratory illness (only respiratory syncytial virus causes more respiratory hospitalisations for this age group). (wikipedia.org)
  • Although scientific interest in them arose because of the diseases they cause, most viruses are beneficial. (wikipedia.org)
  • This virus is the cause of African swine fever. (wikipedia.org)
  • Viruses are a major cause of human waterborne and water-related diseases. (wikipedia.org)
  • Viruses can cause massive human mortality. (wikipedia.org)