News tagged with viruses
(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)—Defective viruses, thought for decades to be essentially garbage unrelated to the transmission of normal viruses, now appear able to play an important role in the spread of disease, new ...
Diseases, Conditions, Syndromes Feb 28, 2013 | 5 / 5 (6) | 0 |
The human body has the ability to ward off viruses by activating a naturally occurring protein at the cellular level, setting off a chain reaction that disrupts the levels of cholesterol required in cell membranes to enable ...
Medical research Apr 17, 2013 | 5 / 5 (6) | 2 |
A study led by researchers at Boston University School of Medicine (BUSM) has identified epigenetic mechanisms that connect a variety of diseases associated with inflammation. Utilizing molecular analyses of gene expression ...
Immunology Mar 01, 2013 | 4.8 / 5 (6) | 0 |
(Medical Xpress)—The inflammation of fat tissue is part of a spiraling series of events that leads to the development of type 2 diabetes in some obese people. But researchers have not understood what triggers ...
Medical research Mar 05, 2013 | 5 / 5 (5) | 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 protein known to be a key player in the development of Parkinson's disease is able to enter and harm cells in the same way that viruses do, according to a Loyola University Chicago Stritch School of Medicine study.
Parkinson's & Movement disorders Apr 25, 2013 | 5 / 5 (5) | 0 |
Researchers have discovered the mechanism behind one of the Ebola virus' most dangerous attributes: its ability to disarm the adaptive immune system.
Medical research May 02, 2013 | 5 / 5 (5) | 0 |
(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 |
Researchers develop universal flu vaccine: New technology could become available to consumers within a decade
(Medical Xpress)—Flu is unpredictable. Influenza viruses are constantly changing—from one season to the next or even within the course of a flu season—making vaccine development difficult.
Medical research Apr 03, 2013 | 5 / 5 (4) | 1 |
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 |
Circumcision drastically alters the microbiome of the penis, changes that could explain why circumcision offers protection against HIV and other viral infections. In a study to be published on April 16 in mBio, the online ...
HIV & AIDS Apr 16, 2013 | 3.4 / 5 (5) | 4 |
A rising percentage of parents say they won't have their teen daughters vaccinated to protect against the human papilloma virus, even though physicians are increasingly recommending adolescent vaccinations, a study by Mayo ...
Pediatrics Mar 18, 2013 | 5 / 5 (3) | 1
(Medical Xpress)—Collaborating scientists from Nationwide Children's Hospital, Baylor Institute for Immunology Research, and Mount Sinai School of Medicine have identified an important mechanism for stimulating protective ...
Diseases, Conditions, Syndromes Mar 25, 2013 | 5 / 5 (3) | 0 |
Until now most experimental vaccines against the highly lethal H5N1 avian influenza virus have lacked effectiveness. But a new vaccine has proven highly effective against the virus when tested in both mice and ferrets. It ...
Diseases, Conditions, Syndromes Mar 25, 2013 | 5 / 5 (3) | 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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