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Swine Flu - Introduction, Classification and History
This article discusses the pathogenic disease in pigs. For the global spread of H1N1 in 2009, see Pandemic Influenza A (H1N1) in 2009.
The swine flu is a viral disease that attacks the pig but is occasionally transmitted to humans.
The swine flu (also known as swine flu or flu pork) is an infectious disease caused by any virus belonging to the family Orthomyxoviridae, which is endemic in populations pig. These strains virus, known as swine influenza virus or SIV (the acronym in English of "swine influenza viruses) have been classified into Influenzavirus C or one of the subtypes of the genus Influenzavirus A (being the best known strains H1N1, H3N2, H3N3, isolated in Quebec - and H1N2, isolated in Japan and Europe).
Although the swine flu does not affect regular human population, there are sporadic cases of infections in humans. Generally, these cases occur in those working with poultry and pigs, especially those individuals who are heavily exposed to this type of animal, and are at higher risk of infection if they carry any viral strain that is also capable to infect humans. This is because the SIV can mutate and additionally, through a process called re-acquire characteristics that allow transmission between people. Also have the ability to change its structure to prevent that the defenses of an organism have the same efficiency, causing the virus to attack again with a greater harmful effect on health.
Importantly, the H1N1 influenza outbreak in 2009 in humans and is known as swine flu swine influenza, apparently is not caused by a swine influenza virus only. Their cause is a new strain of virus of influenza A H1N1 that contains genetic material matched a strain of human influenza virus, a strain of avian influenza virus, and two separate strains of swine influenza virus. The origins of this new strain are unknown and the World Organization for Animal Health (OIE) reports that this strain has been isolated from pigs. It is transmitted easily between humans, due to an ability attributed to a mutation not yet identified, and makes it through the saliva, by air, by close contact between the mucous membranes or through hand-mouth transmission due to contaminated hands. This strain because, in most cases, only seudogripales classic symptoms were mild, and infected persons are recovered successfully without the need for medical care or medication use antivirals.
Micrography in negative staining of influenza A H1N1 virus.
History regarding Swine flu
The H1N1 is a descendant of the Spanish Flu which was a pandemic disease in the 2nd decade of the 20 th century during 1918-1920 . After the completion of the pandemic virus persisted in pigs, and with it the descendants of the 1918 virus have circulated in humans over the course of the twentieth century, contributing to the appearance of normal seasonal influenza annually. However, direct transmission from pigs to humans is quite rare, with only 12 cases have shown in the United States since 2005.
The influenza virus has been considered one of the most elusive until now known by medical science because of its constant change to get around the antibody protectors have been developed after a previous exposure or flu vaccines. Every two or three years, the virus undergoes minor changes. However, about every decade, after which a large part of the world population has reached some level of resistance to these minor changes, the virus is evolving dramatically, allowing you to easily infect a large population groups across the world, often affecting hundreds of millions of people whose immune defenses are not adequate to withstand the onslaught. The influenza virus is also known for making small changes in how very short periods of time. For example, during the Spanish flu pandemic, the initial wave of illness was relatively mild and controlled, while the second wave a year later was highly lethal.
By mid-century, in 1957, a pandemic of Asian flu infected more than 45 million people in Northern America, killing 70,000 people. In total almost caused 2 million deaths worldwide. Eleven years later, from 1968 to 1969 pandemic of influenza in Hong Kong affecting over 50 million people, causing some 33,000 deaths and causing about $ 3900 million dollars in expenses. In 1976, some 500 soldiers were infected with swine flu in a few weeks. However, at the end of that month, investigators found that the virus had "mysteriously disappeared", literally. During an average year in a country like the United States, there are approximately 50 million cases of influenza "normal", which kill about 36,000 people. Most patients affected are part of groups at risk as extremely young or old, sick and pregnant women, with a large percentage of deaths due to complications such as pneumonia.
Medical researchers around the world have admitted that the swine flu virus could mutate into something as deadly as the Spanish flu and are watching carefully the last outbreak of swine flu in 2009 in order to create a contingency plan for a possible pandemic imminent global. Many countries have taken precautionary measures and education to reduce the chances of this happening.
Military hospital during the Spanish flu pandemic
Classification of swine flu
It is a virus belonging to the family Orthomyxoviridae, which includes the viruses causing the flu. The only species of this genus is called "influenza C".
It has been confirmed that influenza C viruses infect humans and pigs, causing flu. However, influenza type C is not very common in comparison with influenza A virus and influenza B virus, but can become severe and cause epidemics premises.
It is known that the swine flu caused by viruses of influenza A (H1N1), H1N2, H3N1, H3N2 and H2N3.
In the town there are three subtypes of swine influenza A (H1N1, H3N2 and H1N2) circulating throughout the world. In the United States, the H1N1 subtype has been a frequent cause of infection among the population before swine until 1998, but since late August of that year, the H3N2 subtype was isolated from pigs. Since 2004, the H3N2 virus strains isolated in Turkey and United States, but came to find genetic traces of human (HA, NA and PB1), swine (NS, NP, and M) and poultry (PB2 and PA ).
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