
[[Image:Influenza_virus.png|frame|Negatively stained flu virions. These were the causative agent of the Hong Kong Flu pandemic. ]] Influenza (or as it is commonly known, the flu or the grippe) is a contagious disease caused by an RNA virus of the orthomyxoviridae family. It rapidly spreads around the world in seasonal epidemics, imposing considerable economic burden in the form of health care costs and lost productivity. Major genetic changes in the virus have caused three influenza pandemics in the 20th century, killing many millions of people. The name comes from the old medical belief in unfavourable astrology ''influences'' as the cause of the disease. == Types == There are three types of the virus: * Influenza A viruses that infect mammal and birds * Influenza B viruses that infect only humans * Influenza C viruses that infect only humans The A type of influenza virus is the type most likely to cause epidemic and pandemic. This is because the influenza A virus can undergo antigenic shift and present a new immune target to susceptible people. Populations tend to have more resistance to influenza B and C because they only undergo antigenic drift and have more similarity with previous strains. Influenza A viruses can be further classified based on the viral capsid proteins haemagglutinin (HA or H) and neuraminidase (NA or N) that are essential to the virus' life cycle. Fifteen H subtypes and nine N subtypes have been identified for influenza A virus. Only one H subtype and one N subtype have been identified for influenza B virus. At present, the most common antigenic variants of influenza A virus are H1N1 and H3N2. (Yohannes et al., 2004) Yet further variation exists, thus specific influenza strain isolates are identified by a standard nomenclature specifying virus type, geographical location where first isolated, year of isolation, sequential number of isolation, and HA and NA subtype (Yohannes ''et al'' 2004) Examples of the nomenclature are A/Moscow/10/99 (H3N2) and B/Hong Kong/330/2001. The term superflu is used to refer to a strain of flu that spreads unusually quickly, is unusually virulent, or is for which the host is unusually unresponsive to treatment. Thus, there is a tendency to apply the term to strains which cause epidemics or pandemics. There is no exact scientific definition of a superflu. == History== There were several serious outbreaks of influenza in the 20th century. The most famous (and the most lethal) was the Spanish Flu pandemic (type A influenza, H1N1 strain), which lasted from 1918 to 1919 and is believed to have killed more people in total than World War I. Lesser flu pandemics included the 1957 Asian Flu (type A, H2N2 strain) and the 1968 Hong Kong Flu (type A, H3N2 strain). Although there were scares in New Jersey in 1976 (the Swine Flu), worldwide in 1977 (the Russian Flu), and in Hong Kong in 1997 (Avian influenza), there have been no major pandemics subsequent to the 1968 infection. Increased immunity from antibody and the development of flu vaccines have limited the spread of the virus and so far prevented any further pandemics. == Symptoms == The virus attacks the respiratory system, is transmitted from person to person by saliva droplets expelled by coughing, and causes the following symptoms: * Fever * Headache * Tiredness (can be extreme) * Dry cough * Sore throat * nose congestion * Sneezing * Irritated eyes * Body aches * Extreme coldness Influenza's effects are much more severe and last longer than those of the common cold. Recovery takes about one to two weeks. Influenza can be deadly, especially for the weak, old or chronically ill. Some flu Pandemic have killed millions of people. Most people who get influenza will recover in one to two weeks, but others will develop life-threatening complications (such as pneumonia). Millions of people in the United States (about 10% to 20% of U.S. residents) are infected with influenza each year. An average of about 36,000 people per year in the United States die from influenza, and 114,000 per year are admitted to a hospital as a result of influenza. Even healthy people can be affected, and serious problems from influenza can happen at any age. People age 65 years and older, people of any age with chronic medical conditions, and very young children are more likely to get complications from influenza. Pneumonia, bronchitis, sinus, and ear infections are four examples of such complications. The flu can make chronic health problems worse. For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic congestive heart failure may have worsening of this condition that is triggered by the flu. == Variability == Influenza is an extremely variable disease; similar viruses are found in pigs and domestic fowl. In areas where there are high concentrations of humans, pigs and birds in close proximity, such as parts of Asia, simultaneous infections across species enable genetic material to be exchanged between the various strains of flu. This appears to be the principal method by which new infectious strains arise. It is believed that sooner or later, a recombination may occur to produce a strain as lethal as the 1918 virus. In late 1997, a new strain of avian influenza (also known as ''bird flu'') originating from chickens infected 18 people in Hong Kong, of whom 6 died. This strain did not appear to be readily transmissible from human to human, but such a high mortality rate, and the possibility of a further recombination to make it more infectious, meant that the risk was considered so great that all domestic poultry in Hong Kong was slaughtered. Avian influenza transmissible to humans resurfaced in January 2004 in Cambodia, Vietnam, and Thailand. == Flu season == Influenza reaches peak prevalence in winter, and because the Northern Hemisphere and Southern Hemisphere have winter at different times of the year there are actually two flu seasons each year. Hope-Simpson (1981) observed that influenza outbreaks are globally ubiquitous and consistently occur six months following the time of maximum solar radiation in an area. Therefore the World Health Organization makes two vaccine formulations every year, one for the Northern and one for the Southern Hemisphere. While most influenza outbreaks in the Northern Hemisphere tend to peak in January or February, not all do. For example, the Spanish_Flu reached peak virulence during late spring and summer worldwide, and not until October in the US. It remains unclear why outbreaks of the flu occur seasonally rather than uniformly throughout the year. One possible explanation is that, because people are indoors more often during the winter, they are in close contact more often and this is enough to trigger the outbreak. Another is that the cold weakens the immune system; however, the virus is contracted in a warm indoor environment in which it can thrive. == Prevention == It is possible to get vaccinated against influenza, however, due to the high mutability of the virus a particular flu vaccine formulation usually only works for about a year. The World Health Organization co-ordinates the contents of the vaccine each year to contain the most likely strains of the virus to attack the next year. The flu vaccine is usually recommended for anyone in a high-risk group who would be likely to suffer complications from influenza. == Treatment == Antiviral treatments that have proven effective in influenza are amantadine, rimantadine, zanamivir, oseltamivir and ribavirin. As most of these substances are expensive, various healthcare organisations and insurers only support their use where this would make a significant difference, e.g. in the elderly. A trademarked elderberry extract, may aid in shortening the duration of an episode of influenza once contracted, though it has no notable preventive effects (Zakay-Rones ''et al'' 1995). == References == *Hope-Simpson RE (1981). The role of season in the epidemiology of influenza. ''J Hyg (Lond)'' 86 (1), 35-47. PMID 7462597 *Yohannes K, Roche P, Hampson A, Miller M, Spencer J (2004). Annual report of the National Influenza Surveillance Scheme, 2003. ''Commun Dis Intell'' 28 (2), 160-8. PMID 15460951 *Zakay-Rones Z, Varsano N, Zlotnik M, Manor O, Regev L, Schlesinger M, Mumcuoglu M. ''Inhibition of several strains of influenza virus in vitro and reduction of symptoms by an elderberry extract (Sambucus nigra L.) during an outbreak of influenza B Panama.'' J Altern Complement Med. 1995 Winter;1(4):361-9. PMID 9395631. == See also == * Infectious diseases * Pandemic == External links == * ''Some of this article was originally from the public domain CDC publication http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm'' * [http://www.who.int/csr/disease/influenza/en/ WHO flu home page] * [http://www.who.int/mediacentre/factsheets/fs211/en/ WHO flu fact sheet] * [http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm CDC flu page] * [http://news.bbc.co.uk/2/hi/health/3719990.stm BBC] * [http://influenzapandemic.blogspot.com Latest Influenza Pandemic News] Infectious diseases Viruses fa:آنفلوآنزا
''Some of this article has been taken from the public domain CDC publication http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm '' ==Stomach flu -- myth?== The web suggests that the "stomach flu" is an actual disease, though the terminology is obviously unfortunate and not precise. The common distinction seems to lie between "upper respiratory flu" and "intestinal flu". The first one is influenza the second one is not. However, both terms exist and stomach flu does neither just refer to side effects of influenza, nor is it a general description of the symptoms given in the article. Yet, it seems that it is sometimes used to label a group of viral infections rather than a specific disease. However these problems have a common general treatment and so they may even deserve a new article. I am no expert and have no reliable sources, so I won't edit here. Though I generally would not trust the web, here are some links that give a hint at this possible alternative meaning: * http://scc.uchicago.edu/stomachflu.htm * http://www.parents.com/articles/health/5172.jsp :Quote from this page: :"Although everyone refers to vomiting and diarrhea as stomach flu, these problems are usually caused by a gastrointestinal virus (a true "flu" is influenza, a respiratory infection). Rotavirus is the most common culprit in young children;" * http://www.the-health-pages.com/education/stomache_flu.html Even if stomach flu is considered too unclear or improper terminology, one should have pointers to diseases that would commonly be labeled this way. --User:Markus Krötzsch 20:51, 20 Jul 2004 (UTC) I added the top-of-article Dab for "Influenza", and the distinct Dab page Flu, for related reasons. They each have to do with one of two related confusions: # One is the misleading standard usage of flu as a synonym for both "stomach flu" and "influenza"; # the other is the understandable but mistaken use of "influenza" as a synonym for "stomach flu", by people who correctly deduce that "flu" is derived from "influenza" but don't realize that "influenza" is no longer a more formal name for "stomach flu". Further discussion of this (which has not yet changed my opinion that both are needed) is at Talk:Flu; i suggest there be single discussion ''there''.
--User:JerzyUser talk:Jerzy 07:10, 2005 Feb 24 (UTC) == what's the name == What's the name of the company that was supposed to produce a huge quantity of flu shots for the british and the north american market, but had to redraw most of there million flu shots due to unhygienic production processes? it happened in the season 2004 / 2005. thanks, --User:Abdull 16:04, 2 Jan 2005 (UTC) :I believe the company's name is "Chiron Corporation." User:Joy Stovall 17:16, Jan 2, 2005 (UTC) == Avian influenza update needed == According to the [http://www.who.int/csr/don/2005_01_21/en/ latest update] by [http://www.who.int/en/ WHO], avian influenza is most likely contracted by contact with duck blood and not communicable from human to human, and this is why we did not see a larger outbreak of the virus. Does anybody else think this should be added to the main page? I'd update it myself if I wasn't sick at home concerned that I might have the flu... - Christophernicus 06:24, 26 Jan 2005 (UTC) :In accordance with [http://www.who.int/mediacentre/factsheets/avian_influenza/en/ updates] from the WHO, I'm removing the Recent Development section. Avian influenza is transmitted to humans by migratory waterfowl and human-to-human contact has only been confirmed in one unusual case so far. Although a new pandemic is expected sometime, it will not come from avian influenza. - User:Chris Lincoln 09:17, 20 Feb 2005 (UTC)
See other meanings of words starting from letter:
Words begining with Influenza:
Influenza
Influenza
Influenza_epidemic_of_1918
Influenza_Epidemic_of_1918-19
Influenza_virus
Influenza_w/_other_respiratory_manifestations
Influenza_w/_pneumonia
Influenza
[[Image:Influenza_virus.png|frame|Negatively stained flu virions. These were the causative agent of the Hong Kong Flu pandemic. ]] Influenza (or as it is commonly known, the flu or the grippe) is a contagious disease caused by an RNA virus of the orthomyxoviridae family. It rapidly spreads around the world in seasonal epidemics, imposing considerable economic burden in the form of health care costs and lost productivity. Major genetic changes in the virus have caused three influenza pandemics in the 20th century, killing many millions of people. The name comes from the old medical belief in unfavourable astrology ''influences'' as the cause of the disease. == Types == There are three types of the virus: * Influenza A viruses that infect mammal and birds * Influenza B viruses that infect only humans * Influenza C viruses that infect only humans The A type of influenza virus is the type most likely to cause epidemic and pandemic. This is because the influenza A virus can undergo antigenic shift and present a new immune target to susceptible people. Populations tend to have more resistance to influenza B and C because they only undergo antigenic drift and have more similarity with previous strains. Influenza A viruses can be further classified based on the viral capsid proteins haemagglutinin (HA or H) and neuraminidase (NA or N) that are essential to the virus' life cycle. Fifteen H subtypes and nine N subtypes have been identified for influenza A virus. Only one H subtype and one N subtype have been identified for influenza B virus. At present, the most common antigenic variants of influenza A virus are H1N1 and H3N2. (Yohannes et al., 2004) Yet further variation exists, thus specific influenza strain isolates are identified by a standard nomenclature specifying virus type, geographical location where first isolated, year of isolation, sequential number of isolation, and HA and NA subtype (Yohannes ''et al'' 2004) Examples of the nomenclature are A/Moscow/10/99 (H3N2) and B/Hong Kong/330/2001. The term superflu is used to refer to a strain of flu that spreads unusually quickly, is unusually virulent, or is for which the host is unusually unresponsive to treatment. Thus, there is a tendency to apply the term to strains which cause epidemics or pandemics. There is no exact scientific definition of a superflu. == History== There were several serious outbreaks of influenza in the 20th century. The most famous (and the most lethal) was the Spanish Flu pandemic (type A influenza, H1N1 strain), which lasted from 1918 to 1919 and is believed to have killed more people in total than World War I. Lesser flu pandemics included the 1957 Asian Flu (type A, H2N2 strain) and the 1968 Hong Kong Flu (type A, H3N2 strain). Although there were scares in New Jersey in 1976 (the Swine Flu), worldwide in 1977 (the Russian Flu), and in Hong Kong in 1997 (Avian influenza), there have been no major pandemics subsequent to the 1968 infection. Increased immunity from antibody and the development of flu vaccines have limited the spread of the virus and so far prevented any further pandemics. == Symptoms == The virus attacks the respiratory system, is transmitted from person to person by saliva droplets expelled by coughing, and causes the following symptoms: * Fever * Headache * Tiredness (can be extreme) * Dry cough * Sore throat * nose congestion * Sneezing * Irritated eyes * Body aches * Extreme coldness Influenza's effects are much more severe and last longer than those of the common cold. Recovery takes about one to two weeks. Influenza can be deadly, especially for the weak, old or chronically ill. Some flu Pandemic have killed millions of people. Most people who get influenza will recover in one to two weeks, but others will develop life-threatening complications (such as pneumonia). Millions of people in the United States (about 10% to 20% of U.S. residents) are infected with influenza each year. An average of about 36,000 people per year in the United States die from influenza, and 114,000 per year are admitted to a hospital as a result of influenza. Even healthy people can be affected, and serious problems from influenza can happen at any age. People age 65 years and older, people of any age with chronic medical conditions, and very young children are more likely to get complications from influenza. Pneumonia, bronchitis, sinus, and ear infections are four examples of such complications. The flu can make chronic health problems worse. For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic congestive heart failure may have worsening of this condition that is triggered by the flu. == Variability == Influenza is an extremely variable disease; similar viruses are found in pigs and domestic fowl. In areas where there are high concentrations of humans, pigs and birds in close proximity, such as parts of Asia, simultaneous infections across species enable genetic material to be exchanged between the various strains of flu. This appears to be the principal method by which new infectious strains arise. It is believed that sooner or later, a recombination may occur to produce a strain as lethal as the 1918 virus. In late 1997, a new strain of avian influenza (also known as ''bird flu'') originating from chickens infected 18 people in Hong Kong, of whom 6 died. This strain did not appear to be readily transmissible from human to human, but such a high mortality rate, and the possibility of a further recombination to make it more infectious, meant that the risk was considered so great that all domestic poultry in Hong Kong was slaughtered. Avian influenza transmissible to humans resurfaced in January 2004 in Cambodia, Vietnam, and Thailand. == Flu season == Influenza reaches peak prevalence in winter, and because the Northern Hemisphere and Southern Hemisphere have winter at different times of the year there are actually two flu seasons each year. Hope-Simpson (1981) observed that influenza outbreaks are globally ubiquitous and consistently occur six months following the time of maximum solar radiation in an area. Therefore the World Health Organization makes two vaccine formulations every year, one for the Northern and one for the Southern Hemisphere. While most influenza outbreaks in the Northern Hemisphere tend to peak in January or February, not all do. For example, the Spanish_Flu reached peak virulence during late spring and summer worldwide, and not until October in the US. It remains unclear why outbreaks of the flu occur seasonally rather than uniformly throughout the year. One possible explanation is that, because people are indoors more often during the winter, they are in close contact more often and this is enough to trigger the outbreak. Another is that the cold weakens the immune system; however, the virus is contracted in a warm indoor environment in which it can thrive. == Prevention == It is possible to get vaccinated against influenza, however, due to the high mutability of the virus a particular flu vaccine formulation usually only works for about a year. The World Health Organization co-ordinates the contents of the vaccine each year to contain the most likely strains of the virus to attack the next year. The flu vaccine is usually recommended for anyone in a high-risk group who would be likely to suffer complications from influenza. == Treatment == Antiviral treatments that have proven effective in influenza are amantadine, rimantadine, zanamivir, oseltamivir and ribavirin. As most of these substances are expensive, various healthcare organisations and insurers only support their use where this would make a significant difference, e.g. in the elderly. A trademarked elderberry extract, may aid in shortening the duration of an episode of influenza once contracted, though it has no notable preventive effects (Zakay-Rones ''et al'' 1995). == References == *Hope-Simpson RE (1981). The role of season in the epidemiology of influenza. ''J Hyg (Lond)'' 86 (1), 35-47. PMID 7462597 *Yohannes K, Roche P, Hampson A, Miller M, Spencer J (2004). Annual report of the National Influenza Surveillance Scheme, 2003. ''Commun Dis Intell'' 28 (2), 160-8. PMID 15460951 *Zakay-Rones Z, Varsano N, Zlotnik M, Manor O, Regev L, Schlesinger M, Mumcuoglu M. ''Inhibition of several strains of influenza virus in vitro and reduction of symptoms by an elderberry extract (Sambucus nigra L.) during an outbreak of influenza B Panama.'' J Altern Complement Med. 1995 Winter;1(4):361-9. PMID 9395631. == See also == * Infectious diseases * Pandemic == External links == * ''Some of this article was originally from the public domain CDC publication http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm'' * [http://www.who.int/csr/disease/influenza/en/ WHO flu home page] * [http://www.who.int/mediacentre/factsheets/fs211/en/ WHO flu fact sheet] * [http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm CDC flu page] * [http://news.bbc.co.uk/2/hi/health/3719990.stm BBC] * [http://influenzapandemic.blogspot.com Latest Influenza Pandemic News] Infectious diseases Viruses fa:آنفلوآنزا
Influenza
''Some of this article has been taken from the public domain CDC publication http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm '' ==Stomach flu -- myth?== The web suggests that the "stomach flu" is an actual disease, though the terminology is obviously unfortunate and not precise. The common distinction seems to lie between "upper respiratory flu" and "intestinal flu". The first one is influenza the second one is not. However, both terms exist and stomach flu does neither just refer to side effects of influenza, nor is it a general description of the symptoms given in the article. Yet, it seems that it is sometimes used to label a group of viral infections rather than a specific disease. However these problems have a common general treatment and so they may even deserve a new article. I am no expert and have no reliable sources, so I won't edit here. Though I generally would not trust the web, here are some links that give a hint at this possible alternative meaning: * http://scc.uchicago.edu/stomachflu.htm * http://www.parents.com/articles/health/5172.jsp :Quote from this page: :"Although everyone refers to vomiting and diarrhea as stomach flu, these problems are usually caused by a gastrointestinal virus (a true "flu" is influenza, a respiratory infection). Rotavirus is the most common culprit in young children;" * http://www.the-health-pages.com/education/stomache_flu.html Even if stomach flu is considered too unclear or improper terminology, one should have pointers to diseases that would commonly be labeled this way. --User:Markus Krötzsch 20:51, 20 Jul 2004 (UTC) I added the top-of-article Dab for "Influenza", and the distinct Dab page Flu, for related reasons. They each have to do with one of two related confusions: # One is the misleading standard usage of flu as a synonym for both "stomach flu" and "influenza"; # the other is the understandable but mistaken use of "influenza" as a synonym for "stomach flu", by people who correctly deduce that "flu" is derived from "influenza" but don't realize that "influenza" is no longer a more formal name for "stomach flu". Further discussion of this (which has not yet changed my opinion that both are needed) is at Talk:Flu; i suggest there be single discussion ''there''.
--User:JerzyUser talk:Jerzy 07:10, 2005 Feb 24 (UTC) == what's the name == What's the name of the company that was supposed to produce a huge quantity of flu shots for the british and the north american market, but had to redraw most of there million flu shots due to unhygienic production processes? it happened in the season 2004 / 2005. thanks, --User:Abdull 16:04, 2 Jan 2005 (UTC) :I believe the company's name is "Chiron Corporation." User:Joy Stovall 17:16, Jan 2, 2005 (UTC) == Avian influenza update needed == According to the [http://www.who.int/csr/don/2005_01_21/en/ latest update] by [http://www.who.int/en/ WHO], avian influenza is most likely contracted by contact with duck blood and not communicable from human to human, and this is why we did not see a larger outbreak of the virus. Does anybody else think this should be added to the main page? I'd update it myself if I wasn't sick at home concerned that I might have the flu... - Christophernicus 06:24, 26 Jan 2005 (UTC) :In accordance with [http://www.who.int/mediacentre/factsheets/avian_influenza/en/ updates] from the WHO, I'm removing the Recent Development section. Avian influenza is transmitted to humans by migratory waterfowl and human-to-human contact has only been confirmed in one unusual case so far. Although a new pandemic is expected sometime, it will not come from avian influenza. - User:Chris Lincoln 09:17, 20 Feb 2005 (UTC)
See other meanings of words starting from letter:
I
IA | IB | IC | ID | IE | IF | IG | IH | IJ | IK | IL | IM | IN | IO | IP | IR | IS | IT | IU | IW | IX | IY | IZ |Words begining with Influenza:
Influenza
Influenza
Influenza_epidemic_of_1918
Influenza_Epidemic_of_1918-19
Influenza_virus
Influenza_w/_other_respiratory_manifestations
Influenza_w/_pneumonia
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