News tagged with virus
Fred Hutchinson Cancer Research Center and University of Washington scientists have identified a class of immune cells that reside long-term in the genital skin and mucosa and are believed to be responsible for suppressing ...
Immunology May 08, 2013 | 5 / 5 (4) | 2 |
(Medical Xpress)—Recent scientific papers from China suggest a vigilant watch should be kept on the development of bird flu viruses, as a new strain has been identified and previously known viruses have ...
Diseases, Conditions, Syndromes May 03, 2013 | 3 / 5 (2) | 1 |
(Medical Xpress)—A fresh round of trials to evaluate gene therapy for the heart is set to begin in a couple of weeks. The British Heart Foundation will be sponsoring the study, which seeks to replace defective ...
Medical research May 01, 2013 | 4.2 / 5 (5) | 0 |
Viruses have historically been classified into one of two types – those with an outer lipid-containing envelope and those without an envelope. For the first time, researchers at the University of North ...
Diseases, Conditions, Syndromes Apr 04, 2013 | 5 / 5 (3) | 1 |
By tracking the very earliest days of one person's robust immune response to HIV, researchers have charted a new route for developing a long-sought vaccine that could boost the body's ability to neutralize ...
HIV & AIDS Apr 03, 2013 | 4.5 / 5 (2) | 0 |
Some diseases are caused by single gene mutations. Current techniques for identifying the disease-causing gene in a patient produce hundreds of potential gene candidates, making it difficult for scientists to pinpoint the ...
Genetics Mar 18, 2013 | 5 / 5 (5) | 0 |
A discovery that shows how a novel—and often fatal—virus infects cells may help fight a health threat that has recently emerged on the world stage, researchers report.
Diseases, Conditions, Syndromes Mar 13, 2013 | 4.3 / 5 (3) | 0 |
(Medical Xpress)—Nanoparticles carrying a toxin found in bee venom can destroy human immunodeficiency virus (HIV) while leaving surrounding cells unharmed, researchers at Washington University School of ...
HIV & AIDS Mar 08, 2013 | 5 / 5 (29) | 3 |
(Medical Xpress)—Viruses often spread through the brain in patchwork patterns, infecting some cells but missing others. New research at Washington University School of Medicine in St. Louis helps explain ...
Medical research Mar 07, 2013 | 4 / 5 (2) | 0 |
Medical researchers discover new ways to target, develop and design drugs to prevent and treat viral infection
Researchers at the University of Alberta have discovered a new drug target, developed a new drug and identified a new way to design drugs—all of which could be a winning combination in the battle against viruses.
Medical research 2 hours ago | 4 / 5 (1) | 0 |
The level of immunity to the recently circulating H7N9 influenza virus in an urban and rural population in Vietnam is very low, according to the first population level study to examine human immunity to the virus, which was ...
Diseases, Conditions, Syndromes 22 hours ago | 5 / 5 (1) | 0 |
The hunt for an HIV vaccine has gobbled up $8 billion in the past decade, and the failure of the most recent efficacy trial has delivered yet another setback to 26 years of efforts.
HIV & AIDS May 19, 2013 | 5 / 5 (1) | 0
Big names in medicine are set to give an upbeat assessment of the war on AIDS on Tuesday, 30 years after French researchers identified the virus that causes the disease.
HIV & AIDS May 18, 2013 | 5 / 5 (2) | 0
Scientists at the University of California, Davis, detected the H1N1 (2009) virus in free-ranging northern elephant seals off the central California coast a year after the human pandemic began, according ...
Diseases, Conditions, Syndromes May 15, 2013 | not rated yet | 1 |
Researchers have identified the dose of dengue virus in human blood that is required to infect mosquitoes when they bite. Mosquitoes are essential for transmitting the virus between people so the findings have important implications ...
Diseases, Conditions, Syndromes May 13, 2013 | not rated yet | 0 |
I: dsDNA viruses II: ssDNA viruses III: dsRNA viruses IV: (+)ssRNA viruses V: (−)ssRNA viruses VI: ssRNA-RT viruses VII: dsDNA-RT viruses
A virus (from the Latin virus meaning toxin or poison) is a microscopic infectious agent that can reproduce only inside a host cell. Viruses infect all types of organisms: from animals and plants, to bacteria and archaea. Since the initial discovery of tobacco mosaic virus by Martinus Beijerinck in 1898, more than 5,000 types of virus have been described in detail, although most types of virus remain undiscovered. Viruses are ubiquitous, as they are found in almost every ecosystem on Earth, and are the most abundant type of biological entity on the planet. The study of viruses is known as virology, and is a branch of microbiology.
Viruses consist of two or three parts: all viruses have genes made from either DNA or RNA, long molecules that carry genetic information; all have a protein coat that protects these genes; and some have an envelope of fat that surrounds them when they are outside a cell. Viruses vary in shape from simple helical and icosahedral shapes, to more complex structures. They are about 1/100th the size of bacteria. The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—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, which increases genetic diversity.
Viruses spread in many ways; plant viruses are often transmitted from plant to plant by insects that feed on sap, such as aphids, while animal viruses can be carried by blood-sucking insects. These disease-bearing organisms are known as vectors. Influenza viruses are spread by coughing and sneezing, and others such as norovirus, are transmitted by the faecal-oral route, when they contaminate hands, food, or water. Rotaviruses are often spread by direct contact with infected children. HIV is one of several viruses that are transmitted through sexual contact.
Not all viruses cause disease, as many viruses reproduce without causing any obvious harm to the infected organism. Viruses such as hepatitis B can cause life-long or chronic infections, and the viruses continue to replicate in the body despite the hosts' defence mechanisms. In some cases, these chronic infections might be beneficial as they might increase the immune system's response against infection by other pathogens. However, in most cases viral infections in animals cause an immune response that eliminates the infecting virus. These immune responses can also be produced by vaccines that give lifelong immunity to a viral infection. Microorganisms such as bacteria also have defences against viral infection, such as restriction modification systems. Antibiotics have no effect on viruses, but antiviral drugs have been developed to treat both life-threatening and more minor infections.
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