A virus (from the Latin virus meaning toxin A toxin is a poisonous substance produced by living cells or organisms. (Although technically man is a living organism, man-made substances created by artificial processes usually aren't considered toxins by this definition.) or poison In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism. Legally and in hazardous chemical labelling, poisons are especially toxic substances; less toxic substances are labelled ") is an infectious agent A pathogen (from Greek πάθος path "suffering, passion", and γἰγνομαι gignomai (gen-) "I give birth to"), infectious agent, or (more commonly) germ, is a biological agent that causes disease or illness to its host. There are several substrates and pathways whereby pathogens can invade a host; the principal pathways too small to be seen directly with a light microscope The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest and simplest of the microscopes. However, new designs of digital microscopes are now available which use a CCD camera to. They are not made of cells The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular . Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion and can only replicate inside the cells of another organism (the viruses' host In biology, a host is an organism that harbors a virus or parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna. Examples of such interactions include a cell being host to a virus, a legume plant hosting). Viruses infect all types of organisms, from animals Animals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and independently. All animals are also and plants Plants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The scientific study of plants, known as botany, has identified about 350,000 extant species of plants, defined as seed plants, bryophytes, ferns and fern allies. As of 2004, to bacteria The bacteria ( [bækˈtɪərɪə] ; singular: bacterium)[α] are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste, water, and and archaea The Archaea [ɑrˈkiə] are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon (sometimes spelled "archeon"). They have no cell nucleus or any other organelles within their cells. In the past they were viewed as an unusual group of bacteria and named archaebacteria but since the.[1] Since the initial discovery of tobacco mosaic virus Tobacco mosaic virus is an RNA virus that infects plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns (mottling and discoloration) on the leaves (hence the name). TMV was the first virus to be discovered. Although it was known from the late 19th century that an infectious disease was by Martinus Beijerinck Martinus Willem Beijerinck was a Dutch microbiologist and botanist. He was born in Amsterdam in 1898,[2] about 5,000 of them have been described in detail,[3] although there are millions of different types of viruses.[4] Viruses are found in almost every ecosystem An ecosystem is a natural unit consisting of all plants, animals and micro-organisms in an area functioning together with all of the physical (abiotic) factors of the environment. Ecosystems can be permanent or temporary. An ecosystem is a unit of interdependent organisms which share the same habitat. Ecosystems usually form a number of food webs on Earth and these minute structures are the most abundant type of biological entity.[5][6] The study of viruses is known as virology Virology is the study of viruses and virus-like agents: their structure, classification and evolution, their ways to infect and exploit cells for virus reproduction, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. Virology is often considered a part of microbiology or of pathology, a sub-specialty of microbiology Microbiology is the study of microorganisms, which are unicellular or cell-cluster microscopic organisms. This includes eukaryotes such as fungi and protists, and prokaryotes. Viruses, though not strictly classed as living organisms, are also studied. In short; microbiology refers to the study of life and organisms that are too small to be seen.
Viruses consist of two or three parts: all viruses have genes A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cells and pass genetic traits to offspring. A modern working definition of a gene is "a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with made from either DNA Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed or RNA Ribonucleic acid is a biologically important type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate. RNA is very similar to DNA, but differs in a few important structural details: in the cell, RNA is usually single-stranded, while DNA is usually double-, long molecules A molecule is defined as a sufficiently stable, electrically neutral group of at least two atoms in a definite arrangement held together by very strong chemical bonds. Molecules are distinguished from polyatomic ions in this strict sense. In organic chemistry and biochemistry, the term molecule is used less strictly and also is applied to charged that carry genetic information; all have a protein Proteins are organic compounds made of amino acids arranged in a linear chain and folded into a globular form. The amino acids in a polymer chain are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by the sequence of a gene, which is coat that protects these genes; and some have an envelope Many viruses have viral envelopes covering their protein capsids. The envelopes are typically derived from portions of the host cell membranes (phospholipids and proteins), but include some viral glycoproteins. Functionally, viral envelopes are used to help viruses enter host cells. Glycoproteins on the surface of the envelope serve to identify of fat that surrounds them when they are outside a cell. Viruses vary from simple helical A helix is a special kind of space curve, i.e. a smooth curve in three-space. As a mental image of a helix one may take the spring (although the spring is not a curve, and so is technically not a helix, it does give a convenient mental picture). A helix is characterised by the fact that the tangent line at any point makes a constant angle with a and icosahedral In geometry, an icosahedron is any polyhedron having 20 faces, but usually a regular icosahedron is implied, which has equilateral triangles as faces shapes, to more complex structures. Most viruses are about one hundred times smaller than an average bacterium. The origins of viruses in the evolutionary history of life The evolutionary history of life on Earth traces the processes by which living and fossil organisms evolved. It stretches back over 3,000 million years, possibly as far as 3,800 million years ago, and evolution continues, even in humans. All present-day organisms use the same large set of complex chemical reactions, which indicates that all modern are unclear: some may have evolved In biology, evolution is change in the genetic material of a population of organisms from one generation to the next. Though changes produced in any one generation are normally small, differences accumulate with each generation and can, over time, cause substantial changes in the population, a process that can result in the emergence of new from plasmids A plasmid is an extra-chromosomal DNA molecule separate from the chromosomal DNA which is capable of replicating independently of the chromosomal DNA. In many cases, it is circular and double-stranded. Plasmids usually occur naturally in bacteria, but are sometimes found in eukaryotic organisms—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer Horizontal gene transfer , also Lateral gene transfer (LGT), is any process in which an organism incorporates genetic material from another organism without being the offspring of that organism. By contrast, vertical transfer occurs when an organism receives genetic material from its ancestor, e.g. its parent or a species from which it evolved, which increases genetic diversity Genetic diversity is a level of biodiversity that refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.[7]
Viruses spread in many ways; plant viruses are often transmitted from plant to plant by insects that feed on sap Sap is a fluid transported in xylem cells or phloem sieve tube elements of a plant. Fluid found in the vacuoles of other cells is sometimes referred to as "cell sap". Other liquid compounds found in plants or exuded by plants, such as latex, resins or mucilage, are sometimes incorrectly referred to as sap, such as aphids Aphids, also known as plant lice , are small plant-eating insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions. The damage they do to plants has made them enemies of farmers and gardeners the world over, but from a purely zoological standpoint they are a, while animal viruses can be carried by blood-sucking Hematophagy is the habit of certain animals of feeding on blood (from the Greek words, haima "blood" and phagein "to eat"). Since blood is a fluid tissue rich in nutritious proteins and lipids that can be taken without enormous effort, hematophagy has evolved as a preferred form of feeding in many small animals such as worms insects. These disease-bearing organisms are known as vectors Vector is a term used in epidemiology to describe a special type of intermediate host for parasites, including bacteria, protozoa and viruses. A vector is not only required for part of the parasite's developmental cycle, but it also transmits the parasite directly to subsequent hosts. Influenza viruses Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals. The name influenza comes from the Italian influenza, meaning "influence" (Latin: influentia). The most common symptoms of the disease are chills, fever, sore throat, muscle pains, are spread by coughing and sneezing. The norovirus Norovirus is an RNA virus (taxonomic family Caliciviridae) which causes approximately 90% of epidemic non-bacterial outbreaks of gastroenteritis around the world, and may be responsible for 50% of all foodborne outbreaks of gastroenteritis in the US. Norovirus affects people of all ages. The viruses are transmitted by faecally contaminated food or and rotaviruses Rotavirus is a genus of double-stranded RNA virus in the family Reoviridae. It is the leading single cause of severe diarrhoea among infants and young children, and is one of several viruses that cause infections commonly known as stomach flu, despite having no relation to influenza. By the age of five, nearly every child in the world has been, common causes of viral gastroenteritis Gastroenteritis is inflammation of the gastrointestinal tract, involving both the stomach and the small intestine (see also gastritis and enteritis) and resulting in acute diarrhea. The inflammation is caused most often by an infection from certain viruses or less often by bacteria, their toxins, parasites, or an adverse reaction to something in, are transmitted by the faecal-oral route and are passed from person to person by contact, entering the body in food or water. HIV Human immunodeficiency virus is a lentivirus (a member of the retrovirus family) that causes acquired immunodeficiency syndrome (AIDS), a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or is one of several viruses transmitted through sexual contact or by exposure to infected blood.
Viral infections in animals provoke an immune response that usually eliminates the infecting virus. These immune responses can also be produced by vaccines A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains a small amount of an agent that resembles a microorganism. The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune system can more easily recognize, which give immunity Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide range of pathogens irrespective of antigenic to specific viral infections. However, some viruses including HIV and those causing viral hepatitis Viral hepatitis is liver inflammation due to a viral infection. It may present in acute or chronic forms. The most common causes of viral hepatitis are the five unrelated hepatotropic viruses Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E. In addition to the hepatitis viruses, other viruses that can also cause hepatitis evade these immune responses and cause chronic In medicine, a chronic disease is a disease that is long-lasting or recurrent. The term chronic describes the course of the disease, or its rate of onset and development. A chronic course is distinguished from a recurrent course; recurrent diseases relapse repeatedly, with periods of remission in between. As an adjective, chronic can refer to a infections. Microorganisms also have defences against viral infection, such as restriction modification systems The restriction modification system is used by bacteria, and perhaps other prokaryotic organisms to protect themselves from foreign DNA, such as the one borne by bacteriophages. This phenomenon was first noticed in the 1950s. Certain bacteria strains were found to inhibit (restrict) the growth of viruses grown in previous strains. This effect was. Antibiotics In common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria. Antibiotics belong to the broader group of antimicrobial compounds, used to treat infections caused by microorganisms, including fungi and protozoa have no effect on viruses, but a few antiviral drugs Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics for bacteria, specific antivirals are used for specific viruses. Unlike antibiotics, antiviral drugs do not destroy their target pathogen; instead they inhibit their development have been developed. However, there are relatively few antivirals because there are few targets for these drugs to interfere with. This is because a virus reprograms its host's cells to make new viruses and almost all the proteins used in this process are normal parts of the body, with only a few viral proteins.
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Washington Post
Customers can then either move or close the alert, or click "Go to Anti- Virus Center," for recommended next-steps, which may include downloading and running ...
Comcast to send infected-PC alerts ZDNet
Comcast tries pop-up alerts to warn of infections The Associated Press
Comcast to Warn PC Users If They're Infected PC Magazine
TMCnet - MX Logic - www.IdentityTheft.info
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seguridad Como cada cierto tiempo empieza a correr un nuevo virus de MSN Messenger por la red Sigue los mismos criterios de siempre sin embargo hay algunos puntos que resaltar Primero las frases con las que engana
Remy "Se7en"
Sun, 11 Oct 2009 23:40:07 GM
This week will be the AVG (8.5.421) Free Anti-. Virus. Review. Also important to note is as always there will be a new Scam Watch and WTF episode this week. Enjoy. Later Days,. Remy Se7en ...
Q. My laptop has a virus. What is the best virus program i can use to clean it or whatever i have to do.
Asked by DYR - Thu Sep 25 20:21:33 2008 - - 6 Answers - 0 Comments
A. The best antivirus program you can get, is the one that works best for you. I have used Avast 4 Home (free) for almost 5 years without a virus ever getting past it. I do recommend it for any operating system. If you have a virus, it will find it and remove it for you. Thereafter, it updates daily.
Answered by lucee - Thu Sep 25 20:29:18 2008
