Ton projet est intéressant mais il n'y aucune erreur ! C'est dommage que ton projet ne soit pas plus "personnalisé" avec des textes rédigés par toi au lieu d'avoir été "copiés" sur un site ou rédigés par quelqu'un qui est bilangue!
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Influenza
Influenza, commonly known as "the flu", is an infectious disease caused by an influenza virus.Symptoms can be mild to severe. The most common symptoms include: high fever, runny nose, sore throat, muscle and joint pain, headache, coughing, and feeling tired. These symptoms typically begin two days after exposure to the virus and most last less than a week.The cough, however, may last for more than two weeks. In children, there may be diarrhea and vomiting, but these are not common in adults. Diarrhea and vomiting occur more commonly in gastroenteritis, which is an unrelated disease and sometimes inaccurately referred to as "stomach flu" or the "24-hour flu". Complications of influenza may include viral pneumonia, secondary bacterial pneumonia, sinus infections, and worsening of previous health problems such as asthma or heart failure.
Three of the four types of influenza viruses affect humans: Type A, Type B, and Type C. Type D has not been known to infect humans, but is believed to have the potential to do so. Usually, the virus is spread through the air from coughs or sneezes.This is believed to occur mostly over relatively short distances. It can also be spread by touching surfaces contaminated by the virus and then touching the eyes, nose, or mouth. A person may be infectious to others both before and during the time they are showing symptoms. The infection may be confirmed by testing the throat, sputum, or nose for the virus. A number of rapid tests are available; however, people may still have the infection even if the results are negative.A type of polymerase chain reaction that detects the virus's RNA is more accurate.
Frequent hand washing reduces the risk of viral spread, as does wearing a surgical mask. Yearly vaccinations against influenza are recommended by the World Health Organization for those at high risk, and by the Centers for Disease Control and Prevention (CDC) for those six months of age and older. The vaccine is usually effective against three or four types of influenza. It is usually well tolerated.A vaccine made for one year may not be useful in the following year, since the virus evolves rapidly. Antiviral drugs such as the neuraminidase inhibitor oseltamivir, among others, have been used to treat influenza. The benefit of antiviral drugs in those who are otherwise healthy do not appear to be greater than their risks. No benefit has been found in those with other health problems.
Influenza spreads around the world in yearly outbreaks, resulting in about three to five million cases of severe illness and about 290,000 to 650,000 deaths. About 20% of unvaccinated children and 10% of unvaccinated adults are infected each year. In the northern and southern parts of the world, outbreaks occur mainly in the winter, while around the equator, outbreaks may occur at any time of the year. Death occurs mostly in high risk groups—the young, the old, and those with other health problems.[1] Larger outbreaks known as pandemics are less frequent. In the 20th century, three influenza pandemics occurred: Spanish influenza in 1918 (17–100 million deaths), Asian influenza in 1957 (two million deaths), and Hong Kong influenza in 1968 (one million deaths). The World Health Organization declared an outbreak of a new type of influenza A/H1N1 to be a pandemic in June 2009.Influenza may also affect other animals, including pigs, horses, and birds.
Infection control
These are the main ways that influenza spreads
by direct transmission (when an infected person sneezes mucus directly into the eyes, nose or mouth of another person);
the airborne route (when someone inhales the aerosols produced by an infected person coughing, sneezing or spitting);
through hand-to-eye, hand-to-nose, or hand-to-mouth transmission, either from contaminated surfaces or from direct personal contact such as a hand-shake.
Reasonably effective ways to reduce the transmission of influenza include good personal health and hygiene habits such as: not touching the eyes, nose or mouth; frequent hand washing (with soap and water, or with alcohol-based hand rubs); covering coughs and sneezes; avoiding close contact with sick people; and staying home when sick. Avoiding spitting is also recommended. Although face masks might help prevent transmission when caring for the sick, there is mixed evidence on beneficial effects in the community. Smoking raises the risk of contracting influenza, as well as producing more severe disease symptoms.
Since influenza spreads through both aerosols and contact with contaminated surfaces, surface sanitizing may help prevent some infections. Alcohol is an effective sanitizer against influenza viruses, while quaternary ammonium compounds can be used with alcohol so that the sanitizing effect lasts for longer. In hospitals, quaternary ammonium compounds and bleach are used to sanitize rooms or equipment that have been occupied by people with influenza symptoms. At home, this can be done effectively with a diluted chlorine bleach.
Social distancing strategies used during past pandemics, such as closing schools, churches and theaters, slowed the spread of the virus but did not have a large effect on the overall death rate. It is uncertain if reducing public gatherings, by for example closing schools and workplaces, will reduce transmission since people with influenza may just be moved from one area to another; such measures would also be difficult to enforce and might be unpopular. When small numbers of people are infected, isolating the sick might reduce the risk of transmission.
Diagnosis
There are a number of rapid tests for the flu. One is called a Rapid Molecular Assay, when an upper respiratory tract specimen (mucus) is taken using a nasal swab or a nasopharyngeal swab. It should be done within 3–4 days of symptom onset, as upper respiratory viral shedding takes a downward spiral after that.
Treatment
People with the flu are advised to get plenty of rest, drink plenty of liquids, avoid using alcohol and tobacco and, if necessary, take medications such as acetaminophen (paracetamol) to relieve the fever and muscle aches associated with the flu. In contrast, there is not enough evidence to support corticosteroids as additional therapy for influenza. It is advised to avoid close contact with others to prevent spread of infection. Children and teenagers with flu symptoms (particularly fever) should avoid taking aspirin during an influenza infection (especially influenza type B), because doing so can lead to Reye's syndrome, a rare but potentially fatal disease of the liver. Since influenza is caused by a virus, antibiotics have no effect on the infection; unless prescribed for secondary infections such as bacterial pneumonia. Antiviral medication may be effective, if given early (within 48 hours to first symptoms), but some strains of influenza can show resistance to the standard antiviral drugs and there is concern about the quality of the research. High-risk individuals such as young children, pregnant women, the elderly, and those with compromised immune systems should visit the doctor for antiviral drugs. Those with the emergency warning signs should visit the emergency room at once.
History
The word Influenza comes from the Italian language meaning "influence" and refers to the cause of the disease; initially, this ascribed illness to unfavorable astrological influences. It was introduced into English in the mid-eighteenth century during a pan-European epidemic. Archaic terms for influenza include epidemic catarrh, la grippe (from the French, first used by Molyneaux in 1694), sweating sickness, and Spanish fever (particularly for the 1918 flu pandemic strain).
Research
Research on influenza includes studies on molecular virology, how the virus produces disease (pathogenesis), host immune responses, viral genomics, and how the virus spreads (epidemiology). These studies help in developing influenza countermeasures; for example, a better understanding of the body's immune system response helps vaccine development, and a detailed picture of how influenza invades cells aids the development of antiviral drugs. One important basic research program is the Influenza Genome Sequencing Project, which was initiated in 2004 to create a library of influenza sequences and help clarify which factors make one strain more lethal than another, which genes most affect immunogenicity, and how the virus evolves over time.
The sequencing of the influenza genome and recombinant DNA technology may accelerate the generation of new vaccine strains by allowing scientists to substitute new antigens into a previously developed vaccine strain. Growing viruses in cell culture also promises higher yields, less cost, better quality and surge capacity. Research on a universal influenza A vaccine, targeted against the external domain of the transmembrane viral M2 protein (M2e), is being done at the University of Ghent by Walter Fiers, Xavier Saelens and their team and has now successfully concluded Phase I clinical trials. There has been some research success towards a "universal flu vaccine" that produces antibodies against proteins on the viral coat which mutate less rapidly, and thus a single shot could potentially provide longer-lasting protection.
A number of biologics, therapeutic vaccines and immunobiologics are also being investigated for treatment of infection caused by viruses. Therapeutic biologics are designed to activate the immune response to virus or antigens. Typically, biologics do not target metabolic pathways like anti-viral drugs, but stimulate immune cells such as lymphocytes, macrophages, and/or antigen-presenting cells, in an effort to drive an immune response towards a cytotoxic effect against the virus. Influenza models, such as murine influenza, are convenient models to test the effects of prophylactic and therapeutic biologics. For example, lymphocyte T-cell immunomodulator inhibits viral growth in the murine model of influenza.
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