What contributes to antigenic shift in influenza viruses?

What is an antigenic shift?

influenza A viruses can trade genetic materials with the viruses of other species. Two different strains trade or merge material, a process known as an antigenic shift.

What is antigenic shift?

influenza A viruses can trade genetic materials with the viruses of other species. Two different strains trade or merge material, a process known as an antigenic shift.

Does the influenza virus readily change the expressions of its genetic material?

RNA genome of influenza virus is segmented in to 7 pieces. It has the unique property of undergoing two types of genetic variation ie antigenic drift and antigenic shift. In antigenic drift the antigenic variations are minor where genetic recombination take place between strains of two similar species whereas in antigenic shift the recombination take place between strains of dissimilar species leading to major antigenic variations and hence seasonal epidemics.

Is swine flu H1N1 an antigenic shift or drift?

antigenic shift

What are difference between antigen drift and antigenic shift?

Both are mutation occurs in virus (usually influenza). But the difference is: antigenic drift are mutation occurs in viral DNA/RNA that cause a person to be re-infected by the virus. while antigenic shift are mutation occurs in viral characteristic, which cause transition from being able to infect poultry ONLY (not human), --> able to infect BOTH poultry and human.

What is the difference between H1N1 H1N2 H3N2 and H3N1 viruses?

Overview:H1N1, H1N2, and H3N2 are the only known Influenza A virus subtypes currently circulating among humans. All the subtypes listed in the question, i.e., H1N1, H1N2, H3N1 and H3N2 are the known subtypes of influenza A viruses that are endemic in pigs and create influenza in pigs, from which reassortants have formed new strains that can be infective to humans. 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.

How were flu pandemics created?

antigenic shift. That shift produces a new subtype that is different from the two parent viruses. When the new subtype contains genes from the human virus,a pandemic resulted because there was no immunity to the virus and no vaccine to protect against it.

What mechanisms leads to genetic variation?

In two main ways. There is the independent orientation of tetrads in prophase I of meiosis and this gives two ways chromosomes can be inserted into gametes. Then there is crossing over, where the male and female chromosomes, in their tetrads, swap sections of genetic material also in prophase I. When gametes come together to form zygotes then the fertilization is random thus adding more genetic variation to the organism.

Where was the 1957 flu pandemic located Or where did it start?

The "Asian Flu" was a category 2 flu pandemic outbreak of avian influenza that originated in China in early 1956 lasting until 1958. It originated from mutation in wild ducks combining with a pre-existing human strain. The virus was first identified in Guizhou. It spread to Singapore in February 1957, reached Hong Kong by April, and US by June. Death toll in the US was approximately 69,800. Estimates of worldwide deaths caused by this pandemic varies widely depending on source; ranging from 1 million to 4 million, with WHO settling on "about 2 million". Asian Flu was of the H2N2 subtype (a notation that refers to the configuration of the hemagglutinin and neuraminidase proteins in the virus) of type A influenza, and an influenza vaccine was developed in 1957 to contain its outbreak. The Asian Flu strain later evolved via antigenic shift into H3N2 which caused a milder pandemic from 1968 to 1969. Both the H2N2 and H3N2 pandemic strains contained avian influenza virus RNA segments. "While the pandemic human influenza viruses of 1957 (H2N2) and 1968 (H3N2) clearly arose through reassortment between human and avian viruses, the influenza virus causing the 'Spanish flu' in 1918 appears to be entirely derived from an avian source (Belshe 2005)."

Can chickens have orgasms?

Yes. Animals can get STDs. Some breeders will only breed their animals with others that have been tested. Yes, most warm blooded animals can get Chlymidia and Brucellosis. There are others but these are the most commonly seen and very difficult to get rid of once it is in a herd or flock.STDs in AnimalsAccording to Planned Parenthood: "All plants and animals that reproduce sexually may develop sexually transmitted infections." AnswerYes. Animals can get STDs. Some breeders will only breed their animals with others that have been tested. Dolphins are known to have the most sex in the world but the water washes away all of the germs. That's why it is good to have sex underwater. AnswerAnimals have their own STDs. It's unlikely that a human STD would infect an animal. Yes, most warm blooded animals can get Chlymidia and Brucellosis. In fact, one of the reasons that Koalas are endangered in the wild in Australia is a Chlamidia epidemic. There are others but these are the most commonly seen and very difficult to get rid of once it is in a herd or flock.Human STDs are exclusive to humans. These infections do not transmit to other animals. Other mammal STDs do not transmit to people.AnswerSTDs consist of Viruses and Bacteria. Virus are known to mutate, hence MRSA and VRE in humans as these viruses have mutated into slightly different versions of their original virus that we cannot yet combat. This is called Antigenic Drift. When a virus mutates into a completely new strain it is called an Antigenic Shift and requires 2 proteins to change. To quote Madeliene McPherson (epidemiologist in Perth, Western Australia who has lectured all over the world) from her Nursing Lecture handoutsInfluenza B sometimes causes epidemics but influenza type A can sweep across continents and around the world in massive epidemics or pandemicsThese periodic pandemics occur because of antigenic changes in one or both surface glycoproteins of the virus.Antibodies against the Glycoproteins (two proteins found on the surface of the virus) protect us from illness. The proteins are haemagglutin (H) and neuraminidase (N). Mutations in the H and N genes ("antigenic drift") allow influenza variants to emerge that are not susceptible to antibodies against earlier strains.Influenza strains with changed H and or N genes (different antigens) are not recognised by cells and antibodies that protected us against earlier strains.This explains why influenza can recur every winter.Influenza viruses are remarkable because of the frequent antigenic changes that occur.The two surface antigens or influenza undergo antigenic varations independent of each other. Minor changes are known as antigenic drifts and major changes known as antigenic shifts result in the appearance of new subtypes.Antigenic shifts can result from an exchanges of genes (reassortment) between viruses of humans and those of birds and pigs. Following such a major antigenic shift the new virus can cause pandemic by spreading into a population that has little immunity to the changed H and or N antigens.Yes actually they can by mabey having a cub or whatever they had the male can fertilise the females body doing so this could cause a disese

What is polymorphic virus?

A polymorphic virus is a virus that can "shape-shift" from every infection, making it extremely hard for antiviruses using virus signatures to detect viruses to detect it.

Do viruses need light?

no,as we all know that these are intracellular parasites,they may be destroyed in presence of light.they genome may be altered in presence of light such as frame shift ar mutation.