Influenza
hideInfluenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses), 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, severe headache, coughing, weakness and general discomfort. Fever and coughs are the most frequent symptoms. In more serious cases, influenza causes pneumonia, which can be fatal, particularly for the young and the elderly. Although it is often confused with other influenza-like illnesses, especially the common cold, influenza is a much more severe disease than the common cold and is caused by a different type of virus. Influenza may produce nausea and vomiting, particularly in children, but these symptoms are more common in the unrelated gastroenteritis, which is sometimes called "stomach flu" or "24-hour flu".
Typically, influenza is transmitted through the air by coughs or sneezes, creating aerosols containing the virus. Influenza can also be transmitted by bird droppings, saliva, nasal secretions, feces and blood. Infection can also occur through contact with these body fluids or through contact with contaminated surfaces. Airborne aerosols have been thought to cause most infections, although which means of transmission is most important is not absolutely clear. Influenza viruses can be inactivated by sunlight, disinfectants and detergents. As the virus can be inactivated by soap, frequent hand washing reduces the risk of infection.
Influenza spreads around the world in seasonal epidemics, resulting in the deaths of hundreds of thousands annually — millions in pandemic years. Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new strain of the virus in humans. Often, these new strains appear when an existing flu virus spreads to humans from other animal species, or when an existing human strain picks up new genes from a virus that usually infects birds or pigs. An avian strain named H5N1 raised the concern of a new influenza pandemic, after it emerged in Asia in the 1990s, but it has not evolved to a form that spreads easily between people. In April 2009 a novel flu strain evolved that combined genes from human, pig, and bird flu, initially dubbed "swine flu", emerged in Mexico, the United States, and several other nations. WHO officially declared the outbreak to be a "pandemic" on June 11, 2009.
Vaccinations against influenza are usually given to people in developed countries and to farmed poultry. The most common human vaccine is the trivalent influenza vaccine (TIV) that contains purified and inactivated material from three viral strains. Typically, this vaccine includes material from two influenza A virus subtypes and one influenza B virus strain. The TIV carries no risk of transmitting the disease, and it has very low reactivity. A vaccine formulated for one year may be ineffective in the following year, since the influenza virus evolves rapidly, and new strains quickly replace the older ones. Antiviral drugs can be used to treat influenza, with neuraminidase inhibitors being particularly effective.
For more information about Influenza, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with influenza
WHO: Swine flu virus is top strain worldwide
Nov 05, 2009 |
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(AP) -- The World Health Organization's flu chief said the swine flu virus has now become the predominant flu strain worldwide.
When should flu trigger a school shutdown?
Nov 04, 2009 |
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As flu season approaches, parents around the country are starting to face school closures. But how bad should an influenza outbreak be for a school to shut down? A study led by epidemiologists John Brownstein, PhD, and Anne ...
Report on H1N1 cases in California shows hospitalization can occur at all ages, with many severe
Nov 03, 2009 |
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In contrast with some common perceptions regarding 2009 influenza A(H1N1) infections, an examination of cases in California indicates that hospitalization and death can occur at all ages, and about 30 percent of hospitalized ...
Initial results show pregnant women mount strong immune response to one dose of 2009 H1N1 vaccine
Medicine & Health / Medications
Nov 02, 2009 |
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Healthy pregnant women mount a robust immune response following just one dose of 2009 H1N1 influenza vaccine, according to initial results from an ongoing clinical trial sponsored by the National Institute of Allergy and ...
Flu vaccine given to women during pregnancy keeps infants out of the hospital
Nov 02, 2009 |
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Infants born to women who received influenza vaccine during pregnancy were hospitalized at a lower rate than infants born to unvaccinated mothers, according to preliminary results of an ongoing study by researchers at Yale ...
Swine flu deaths jump by 700 in a week: WHO
Oct 30, 2009 |
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The number of swine flu deaths jumped by 700 in a week, reaching more than 5,700 worldwide since the virus was first uncovered in April, World Health Organisation data indicated Friday.
Scientists Propose New Explanation for Flu Virus Antigenic Drift
Oct 29, 2009 |
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(PhysOrg.com) -- Influenza viruses evade infection-fighting antibodies by constantly changing the shape of their major surface protein. This shape-shifting, called antigenic drift, is why influenza vaccines ...
Flying with the flu: Expert panel revisits the danger of air travel during a pandemic
Oct 29, 2009 |
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Attempting to ground planes during pandemics may not be worth the trouble, a panel of experts from the government, academia and the airlines industry heard at a recent meeting in Washington.
New model may help scientists better predict and prevent influenza outbreaks
Oct 29, 2009 |
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(PhysOrg.com) -- Each year, the influenza virus evolves. And each year, public health officials try to predict what the new strain will be and how it will affect the population in order to best combat it.
Scientists discover influenza's Achilles heel: Antioxidants
Oct 29, 2009 |
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As the nation copes with a shortage of vaccines for H1N1 influenza, a team of Alabama researchers have raised hopes that they have found an Achilles' heel for all strains of the flu—antioxidants. In an article appearing in ...
Moderate exercise in mice boosts immune system, diminishes flu's severity
Oct 28, 2009 |
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(PhysOrg.com) -- It appears as though exercise pain does have plenty of gain when it comes to fighting off the severe effects of the flu. A new study by five Iowa State University researchers on mice infected ...
Older patients with dementia at increased risk for flu mortality
Oct 27, 2009 |
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An epidemiological study on pneumonia and influenza (P&I) in adults age 65 and over reports that patients with dementia are diagnosed with flu less frequently, have shorter hospital stays, and have a fifty percent higher ...
Triple-combo drug shows promise against antiviral-resistant H1N1, researcher says (w/ Video)
Oct 27, 2009 |
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An experimental drug cocktail that includes three prescriptions now widely available offers the best hope in developing a single agent to treat drug-resistant H1N1 swine flu, says a virology researcher in the University of ...
The truth about swine flu: Separating fact and rumor
Oct 23, 2009 |
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Swine flu is spreading: 292 U.S. deaths have been confirmed since Aug. 30, and seven times that number are suspected. But rumors about the illness and the vaccine to prevent it are spreading even faster.
Important new novel 2009 H1N1 flu advisory for cardiopulmonary transplantation
Oct 23, 2009 |
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Each year 3-5 million people have severe cases and 250-500,000 die from complications of seasonal influenza world-wide. This year, the novel 2009 H1N1 (nH1N1) influenza, previously called swine flu, has reached pandemic status. ...
