Therefore, it is critical to comprehend the epidemiological and molecular mechanisms by which influenza A viruses acquire the capability to cross species barriers.
Of the influenza viruses currently in worldwide circulation, A H3N2 still has the most severe overall impact. During this century, pandemics occurred in, andeach of which resulted in large numbers of deaths, as noted below.
The other influenza A subtype currently in circulation, type A H1N1also has an interesting history. Free essays on Biology posted on this site were donated by anonymous users and are provided for informational use only.
However, as A H1N1 viruses continue to evolve, they could begin to have a more severe impact on the elderly. The virus that reappeared in was virtually identical to an A H1N1 virus that circulated in This constant changing enables the virus to evade the immune system of its host, so that people are susceptible to influenza virus infection throughout life.
These people include health care personnel and volunteers who work with highrisk patients and people who live in a household with a highrisk person. The free Biology research paper Influenza essay presented on this page should not be viewed as a sample of our on-line writing service.
In the elderly and those with certain chronic medical conditions, the vaccine is often less effective in preventing illness than in reducing the severity of illness and the risk of serious complications and death.
The truth is that influenza vaccine causes no side effects in most people. A second possibility is suggested by evidence that a virus with a similar hemagglutinin may have circulated from the late s to the early s. Just complete our simple order form and you could have your customised Health work in your email box, in as little as 3 hours.
Nevertheless, some older people remember earlier influenza vaccines that did, in fact, produce more unpleasant side effects. Since the side effects associated with these early vaccines, such as fever, headache, muscle aches, and fatigue, were similar to some of the symptoms of influenza, people believed that the vaccine had caused them to get the flu.
Currently, there are three different influenza virus strains, and the vaccine contains viruses representing each strain. Efforts to control the impact of influenza are aimed at types A and B, and the remainder of this discussion will be devoted only to these two types.
Antigenic shift occurs only occasionally. It periodically caused large epidemics, but never on the scale of the pandemic. This process works as follows: Type C infection usually causes either a very mild respiratory illness or no symptoms at all; it does not cause epidemics and does not have the severe public health impact that influenza types A and B do.
The fact that influenza viruses continually change is one of the reasons vaccine must be taken every year.
However, the impact of A H1N1 has been different during its most recent appearance.Introduction Influenza, commonly known as the "flu", is an acute viral infection of the respiratory tract caused by influenza viruses.
Every year, influenza strikes millions of people worldwide. Gazette Spanish Influenza Epidemic There is a sudden outbreak of the Spanish influenza here in the States. This sudden outbreak is said to be caused by vaccinations given to the soldiers over in Europe.
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If you need fresh and competent research / writing on Biology, use the professional writing service offered by our company. View / hide essay. The Influenza Pandemic Of History Essay.
Print Reference this. Disclaimer: The effects of the virus that caused the influenza pandemic of resulted in mortalities and then preventive measures, which had a tremendous impact on. Influenza Essay Influenza is a disease also known as ‘the flu’ which is most common in the U.S. Influenza is caused by a contagious virus that is spread by fluids of coughing, sneezing and direct eye contact from surfaces where serious infection and death occur around the world mostly in winter.Download