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
Aspirin misuse may have made 1918 flu pandemic worse
Oct 02, 2009 |
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The devastation of the 1918-1919 influenza pandemic is well known, but a new article suggests a surprising factor in the high death toll: the misuse of aspirin. Appearing in the November 1 issue of Clinical Infectious Di ...
Human nose too cold for bird flu, says new study
May 15, 2009 |
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(PhysOrg.com) -- Avian influenza viruses do not thrive in humans because the temperature inside a person's nose is too low, according to research published today in the journal PLoS Pathogens. The authors of the ...
What you need to know about swine flu (Update)
Apr 27, 2009 |
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(AP) -- A never-before-seen strain of swine flu has turned killer in Mexico and is causing milder illness in the United States and elsewhere. While authorities say it's not time to panic, they are taking ...
Scientists learn why the flu may turn deadly
May 04, 2009 |
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As the swine flu continues its global spread, researchers from the Children's Hospital of Philadelphia, Pennsylvania, have discovered important clues about why influenza is more severe in some people than it is in others. ...
Swine flu origins revealed
Jun 11, 2009 |
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A new analysis of the current swine-origin H1N1 influenza A virus suggests that transmission to humans occurred several months before recognition of the existing outbreak.
Shades of 1918? New study compares avian flu with a notorious killer from the past
Biology /
Feb 10, 2009 |
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In the waning months of the First World War, a lethal virus known as the Spanish flu (influenza A, subtype H1N1), swept the United States, Europe and Asia in three convulsive waves. The year was 1918. The ...
Scientists identify human monoclonal antibodies effective against bird and seasonal flu viruses
Biology /
Feb 22, 2009 |
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Researchers at the Dana-Farber Cancer Institute, Burnham Institute for Medical Research and the Centers for Disease Control and Prevention have reported the identification of human monoclonal antibodies (mAb) that neutralize ...
Research team finds immune molecule that attacks wide range of flu viruses
Feb 26, 2009 |
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The discovery of the molecule, an antibody known as CR6261, is good news for researchers who hope to design a flu vaccine that would give humans lifelong protection against a majority of influenza viruses. The antibody also ...
In pandemics of the past, caution for the future
May 24, 2009 |
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A novel flu circulated in some American cities in April and May of 1918, causing mild illness and going largely unnoticed. It returned in September, and again in January, eventually killing more than 500,000 people nationwide.
Link found between influenza, absolute humidity
Feb 09, 2009 |
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A new study by Oregon researchers has found a significant correlation between "absolute" humidity and influenza virus survival and transmission. When absolute humidity is low - as in peak flu months of January and February ...
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 ...
Human vaccine against bird flu a reality with new discovery
Mar 02, 2009 |
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A vaccine to protect humans from a bird flu pandemic is within reach after a new discovery by researchers at the University of Melbourne, Australia.
Health authorities rush to tackle killer flu in US, Mexico
Apr 24, 2009 |
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World health authorities on Friday rushed to tackle flu outbreaks in the United States and Mexico that have killed at least 60 people and have pandemic potential.
Swine Flu vs. Seasonal Flu: Be Prepared
Aug 13, 2009 |
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It hit in April but continues to wreak havoc locally and globally. H1N1 -- also known as swine flu -- has sickened over 43,000 people nationwide and it’s not disappearing anytime soon, says University of Cincinnati infectious ...
Mexicans put faith in masks -- but do they work?
Apr 28, 2009 |
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(AP) -- The cloth patches in green, blue and white are everywhere, clamped tight over the mouth and nose of teachers, toddlers, policemen and drunks. Even the statue at the church of St. Jude, patron of lost ...
