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What is the difference between H1N1 H1N2 H3N2 and H3N1 viruses?
Wiki User
∙ 12y ago
H1N1 is the "Swine Flu" subtype of influenza, of which there are several different strains. This subtype is usually seen in humans and pigs. The better known reassortant H1N1 virus strain currently circulating is H1N1/09, the pandemic swine flu virus that caused the pandemic of 2009 and infected humans, pigs, birds, ferrets, dogs, and cats during the pandemic. There are several other less well known strains of the H1N1 subtype.
H1N2 is a common flu in pigs in the Upper Midwest of the US. Until 2011, only one case had been known to occur in humans and that was in 2007 in Michigan. The second ever known case was found in an infant in December 2011 in Minnesota.
H3N1 mostly only infects pigs.
H3N2 is the subtype that produced a strain of flu that caused the Hong Kong Flu and another was the cause of the Fujian Flu, etc. In birds, humans, and pigs, there have been many new strains mutated and this subtype is becoming more prevalent in seasonal influenza.
For background, the meanings of "H" and "N" in the nomenclature:
Hemagglutinin: An important surface protein on the capsid (coat) of the influenza virus that is essential for the reproduction and the spread of the virus in the body in the lytic cycle of virus replication. This protein enables the virus to attach itself to a cell in the respiratory system or other mucous tissue and penetrate it to invade and use the host cell for reproduction. Referred to as the "H" in influenza viruses.
Neuraminidase: An important surface structure protein of the influenza virus that is an essential enzyme for the spread of the virus throughout the respiratory tract. It enables the virus to escape the host cell and infect new cells. Referred to as the "N" in influenza viruses.
See more about the lytic cycle and influenza virus nomenclature in the related questions below.
Types of Influenza VirusesThere are three types of influenza viruses: Types A, B and C. Influenza A and B viruses cause seasonal outbreaks and epidemics of influenza virus infections each flu season. Type A causes all pandemics. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics.Influenza A viruses are divided into subtypes based on the configuration of the two proteins on the surface of the viruses: hemagglutinin (H) and neuraminidase (N). [Not all H1N1 viruses are the same; not all H5N1 viruses are the same.....etc] There are 16 different hemagglutinin subtypes and 9 different neuraminidase subtypes. Influenza A viruses can be further broken down into different strains.
Influenza B viruses are not divided into subtypes. Influenza B viruses also can be further broken down into different strains.
Influenza A (H1N1), A (H3N2), and influenza B strains are included in each year's influenza vaccine. Getting a flu vaccination can protect against influenza A and B viruses. The flu vaccine does not protect against influenza C viruses.
More information including how influenza viruses change: Drift and ShiftInfluenza viruses are dynamic and are continuously mutating, reassorting, and evolving. Influenza viruses can change in two different ways: antigenic drift and antigenic shift. Influenza viruses are changing by antigenic drift all the time, but antigenic shift happens only occasionally. Influenza type A viruses undergo both kinds of changes; influenza type B viruses change only by the more gradual process of antigenic drift.Antigenic drift refers to small, gradual changes that occur through point mutations in the two genes that contain the genetic material to produce the main surface proteins, hemagglutinin, and neuraminidase. These point mutations occur unpredictably and result in minor changes to these surface proteins. Antigenic drift produces new virus strains that may not be recognized by antibodies produced after exposure to earlier influenza strains.
This process works as follows: a person infected with a particular influenza virus strain develops antibodies against that strain. As newer virus strains appear, the antibodies against the older strains might not recognize the "newer" virus to inactivate it, and infection with a new strain can occur. This is one of the main reasons why people can become infected with influenza viruses more than one time and why global surveillance is critical in order to monitor the evolution of human influenza virus stains for selection of which strains should be included in the annual production of influenza vaccine.
In most years, one or two of the three virus strains in the seasonal influenza vaccine are updated to keep up with the changes in the circulating influenza viruses. For this reason, people who want to be immunized against influenza need to be vaccinated every year.
Antigenic shift refers to an abrupt, major change to produce a novel influenza A virus subtype in humans that had not been currently circulating among people (see more information below under Influenza Type A and Its Subtypes).
Antigenic shift can occur either through direct animal (poultry)-to-human transmission or through mixing of human influenza A and animal influenza A virus genes to create a new human influenza A subtype virus through a process called genetic reassortment or reassortant. Antigenic shift results in a new human influenza A subtype.
A global influenza pandemic (worldwide spread) may occur if three conditions are met:
- A new subtype of influenza A virus is introduced into the human population.
- The virus causes serious illness in humans.
- The virus can spread easily from person to person in a sustained manner.
Wiki User
∙ 12y ago
Wiki User
∙ 9y agoH1N1 is a virus strain that circulates among humans, the same virus that caused the swine flu pandemic in 2009. H3N2 is the strain that caused the Hong Kong flu and the Fujian flu.
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What does the A stand for in Influenza A virus?
The A and B in influenza are simply different types of influenza. * Type A: seasonal epidemics. This sub-type is based on changes in surface antigens hemagglutinin and neuraminidase. In humans subtypes H1-H3 and N1-N2 have circulated since 1918 pandemic (due to H1N1). In the last 3 decades the circulating types have been H3N2 and H1N1. * Type B: sporadic outbreaks (long term care facilities)
What are the other types of the flu?
ABC. A is the worst, causes pandemics and epidemics B causes epidemics C is minimally problematic If you're talking about strains, you have 9 types of Hemagglutinin and 16 types of Neuraminidase. So H5N1 (swine flue from a couple years ago) has Hemagluttinin number 5 and Neuraminidase number 1
Do some people with H1N1 get bronchitis?
yes h1n2 should no in vain
Is there a virus called h1n2?
H1N2 is a subtype of the influenza "A" virus - Hong Kong virus of 1968-69 winter and part of other preious influenza epidemics worldwide.
What are the examples of polymorphic viruses?
1260 is a computer virus developed by Mark Washburn in 1989. This virus used a form of polymorphic encryption in it's code which randomized the algorithm used by the virus but kept the core function of it intact. Polymorphic code does this by infecting files with an encrypted copy of itself, then varying it's signature by randomizing its decryption algorithm. Then it repeats. Hope this helped, here's some relevant info on the subject:http://en.wikipedia.org/wiki/1260_(computer_virus)http://en.wikipedia.org/wiki/Mark_Washburnhttp://en.wikipedia.org/wiki/Timeline_of_computer_viruses_and_worms--Answered by Alix Saunders
What does the A stand for in Influenza A virus?
The A and B in influenza are simply different types of influenza. * Type A: seasonal epidemics. This sub-type is based on changes in surface antigens hemagglutinin and neuraminidase. In humans subtypes H1-H3 and N1-N2 have circulated since 1918 pandemic (due to H1N1). In the last 3 decades the circulating types have been H3N2 and H1N1. * Type B: sporadic outbreaks (long term care facilities)
What are the other types of the flu?
ABC. A is the worst, causes pandemics and epidemics B causes epidemics C is minimally problematic If you're talking about strains, you have 9 types of Hemagglutinin and 16 types of Neuraminidase. So H5N1 (swine flue from a couple years ago) has Hemagluttinin number 5 and Neuraminidase number 1
Why is the Swine Flu bad?
Four main virus subtypes - H1N1, H1N2, H3N2 and H3N1 - have been isolated in pigs, though the virus, like all influenza viruses, constantly mutates. When influenza viruses from different species infect pigs, the viruses can trade genes to create new versions that mix swine, human and/or avian influenza.The swine H1N1 virus is not the same as the human H1N1 virus, so vaccines for the latter won't protect from the former.
What Influenza A subtypes can infect humans?
There have been several over the decades. The first one found was the one that pigs get (hence the name), H1N1, in the1930's. Then when people started being able to catch that one or mutations of that one, there is speculation that there could have been several others in retrospect, including the "Spanish Flu" that started the influenza pandemic in 1918, but there are no longer samples to test that hypothesis. Then there was the 1976 swine flu (see more in related questions), and now most recently, the H1N1/09 swine flu, the one that caused the 2009 pandemic and still circulating and making people ill today. See the related questions below, about when swine flu started and what caused the 2009 swine flu to develop, for more details.
What is the difference between H5N1 and Bird Flu?
The two main differences, besides being caused by two different viruses, would be that the H1N1/09 pandemic swine flu spreads very easily from human to human and is symptomatically milder than the Avian flu.H1N1 spreads rapidly from person to person, which led to its being a pandemic in 2009-2010, while the Avian (bird) flu does not spread easily in humans. Bird flu is very rare overall, and spreads mostly from direct bird-to-human exposure. It has had extremely rare cases that spread from human-to-human but only among family members in the same households.Swine flu has comparatively mild symptoms in most people, and causes fewer deaths than even the seasonal flu viruses usually do, while the bird flu is especially virulent and deadly with a mortality rate of 50 to 60 % of those infected.They are both viruses that are relatively new to human infection. The pandemic swine flu (A-H1N1/09) is a new mutation and since there was no direct exposure to the virus before it was found in 2009, there was little resistance to contagion. The Avian "bird" flu (A-H5N1) is also a new virus for humans to get. Avian flu is much more rare among humans than in birds, but it is rarely transmitted to humans, and not by person to person transmission so far.Swine flu is a mutation that caused a new subtype of influenza A. It contains genetic material from the avian flu virus, several strains of hog viruses, and human flu virus.Here are the most common symptoms of each:Avian flu-~ Virus causes lung inflammation~ Immune system over-reacts, creates a lot of white blood cells and a natural virus-fighting chemical (Cytokine)~ Chemical runs in blood stream in such high quantities that it creates tiny holes in the blood vessels~ Plasma leaks out of the holes and into the lungs~ Victim drowns from the insideSwine flu-~ Virus is very similar to seasonal human flu~ Starts with a bad cough and headache~ Fever and fatigue ensue~ After about a week, symptoms are relieved except for the fever and often the cough~ After 24 hours of no fever, you are considered no longer contagiousOn the humorous side:As far as the care goes, with Bird flu you need to seek TWEETMENT, and for swine flu you can apply OINKMENT.
What is the definition of Flu?
Swine influenza (also called swine flu, hog flu, Mexican flu and pig flu) refers to influenza caused by those strains of influenza virus, called swine influenza virus (SIV), that usually infect (is endemic in) pigs.[2] As of 2009 these strains are all found in Influenza C virus and the subtypes of Influenza A virus known as H1N1, H1N2, H3N1, H3N2, and H2N3. Swine influenza is common in pigs in the midwestern United States (and occasionally in other states), Mexico, Canada, South America, Europe (including the United Kingdom, Sweden, and Italy), Kenya, Mainland China, Taiwan, Japan and other parts of eastern Asia.[2] Transmission of swine influenza virus from pigs to humans is not common and properly cooked pork poses no risk of infection. When transmitted, the virus does not always cause human influenza and often the only sign of infection is the presence of antibodies in the blood, detectable only by laboratory tests. When transmission results in influenza in a human, it is called zoonotic Swine Flu. People who work with pigs, especially people with intense exposures, are at risk of catching Swine Flu. However, only about fifty such transmissions have been recorded since the mid-20th century, when identification of influenza subtypes became possible. Rarely, these strains of swine flu can pass from human to human. In humans, the symptoms of swine flu are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. The 2009 flu outbreak in humans, known as "swine flu", is due to a new strain of influenza A virus subtype H1N1 that contained genes most closely related to swine influenza.[3] The origin of this new strain is unknown. However, the World Organization for Animal Health (OIE) reports that this strain has not been isolated in pigs.[4] This strain can be transmitted from human to human,[5] and causes the normal symptoms of influenza.[6] Pigs can become infected with human influenza, and this appears to have happened during the 1918 flu pandemic and the 2009 flu outbreak.
What is the definition of the Swine Flu?
Swine influenza (also called swine flu, hog flu, Mexican flu and pig flu) refers to influenza caused by those strains of influenza virus, called swine influenza virus (SIV), that usually infect (is endemic in) pigs.[2] As of 2009 these strains are all found in Influenza C virus and the subtypes of Influenza A virus known as H1N1, H1N2, H3N1, H3N2, and H2N3. Swine influenza is common in pigs in the midwestern United States (and occasionally in other states), Mexico, Canada, South America, Europe (including the United Kingdom, Sweden, and Italy), Kenya, Mainland China, Taiwan, Japan and other parts of eastern Asia.[2] Transmission of swine influenza virus from pigs to humans is not common and properly cooked pork poses no risk of infection. When transmitted, the virus does not always cause human influenza and often the only sign of infection is the presence of antibodies in the blood, detectable only by laboratory tests. When transmission results in influenza in a human, it is called zoonotic Swine Flu. People who work with pigs, especially people with intense exposures, are at risk of catching swine flu. However, only about fifty such transmissions have been recorded since the mid-20th century, when identification of influenza subtypes became possible. Rarely, these strains of swine flu can pass from human to human. In humans, the symptoms of swine flu are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. The 2009 flu outbreak in humans, known as "swine flu", is due to a new strain of influenza A virus subtype H1N1 that contained genes most closely related to swine influenza.[3] The origin of this new strain is unknown. However, the World Organization for Animal Health (OIE) reports that this strain has not been isolated in pigs.[4] This strain can be transmitted from human to human,[5] and causes the normal symptoms of influenza.[6] Pigs can become infected with human influenza, and this appears to have happened during the 1918 flu pandemic and the 2009 flu outbreak.
