（TI）冬季流感病毒

1`Have you got any diseases during this semster? If so, what it is? What did it feels? 2`Are you the kind of person who catches cold easily? Since the winter comes, what would you do to keep “the flu” away from you? 3`The microbios simply show us a totally different aspect of “the flu” in a virus version, what do you think of these creatures? Zoey: 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: a high fever, runny nose, sore throat, muscle pains, 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 nausea and vomiting, but these are not common in adults. Nausea and vomiting occur more commonly in the unrelated infection gastroenteritis, which is sometimes inaccurately referred to as "stomach flu" or "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. April: Three types of influenza viruses affect people, called Type A, Type B, and Type C. 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 mouth or eyes. 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 if the results are negative. A type of polymerase chain reaction that detects the virus's RNA is more accurate. Rita: Frequent hand washing reduces the risk of viral spread. Wearing a surgical mask is also useful. Yearly vaccinations against influenza are recommended by the World Health Organization for those at high risk. 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. Their benefits 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. Yuki: Influenza spreads around the world in a yearly outbreak, resulting in about three to five million cases of severe illness and about 250,000 to 500,000 deaths. In the Northern and Southern parts of the world, outbreaks occur mainly in winter while in areas around the equator outbreaks may occur at any time of the year. Death occurs mostly in the young, the old and those with other health problems. Larger outbreaks known as pandemics are less frequent. In the 20th century, three influenza pandemicsoccurred: Spanish influenza in 1918 (~50 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. Stuart: When an infected person sneezes or coughs more than half a million virus particles can be spread to those close by. In otherwise healthy adults, influenza virus shedding (the time during which a person might be infectious to another person) increases sharply one-half to one day after infection, peaks on day 2 and persists for an average total duration of 5 days—but can persist as long as 9 days. In those who develop symptoms from experimental infection (only 67% of healthy experimentally infected individuals), symptoms and viral shedding show a similar pattern, but with viral shedding preceding illness by one day. Children are much more infectious than adults and shed virus from just before they develop symptoms until two weeks after infection. In immunocompromised people, viral shedding can continue for longer than two weeks. Zoey: Influenza can be spread in three main ways: 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) and through hand-to-eye, hand-to-nose, or hand-to-mouth transmission, either from contaminated surfaces or from direct personal contact such as a handshake. The relative importance of these three modes of transmission is unclear, and they may all contribute to the spread of the virus. In the airborne route, the droplets that are small enough for people to inhale are 0.5 to 5 µm in diameter and inhaling just one droplet might be enough to cause an infection. Although a single sneeze releases up to 40,000 droplets, most of these droplets are quite large and will quickly settle out of the air. How long influenza survives in airborne droplets seems to be influenced by the levels of humidity and UV radiation, with low humidity and a lack of sunlight in winter aiding its survival. April: The influenza vaccine is recommended by the World Health Organization and United States Centers for Disease Control and Prevention for high-risk groups, such as children, the elderly, health care workers, and people who have chronic illnesses such as asthma, diabetes, heart disease, or are immuno-compromised among others. In healthy adults it is modestly effective in decreasing the amount of influenza-like symptoms in a population. Evidence is supportive of a decreased rate of influenza in children over the age of two. In those with chronic obstructive pulmonary disease vaccination reduces exacerbations, it is not clear if it reduces asthma exacerbations. Evidence supports a lower rate of influenza-like illness in many groups who are immunocompromised such as those with: HIV/AIDS, cancer, and post organ transplant. In those at high risk immunization may reduce the risk of heart disease. Whether immunizing health care workers affects patient outcomes is controversial with some reviews finding insufficient evidence and others finding tentative evidence. Rita: Due to the high mutation rate of the virus, a particular influenza vaccine usually confers protection for no more than a few years. Every year, the World Health Organization predicts which strains of the virus are most likely to be circulating in the next year (see Historical annual reformulations of the influenza vaccine), allowing pharmaceutical companies to develop vaccines that will provide the best immunity against these strains. The vaccine is reformulated each season for a few specific flu strains but does not include all the strains active in the world during that season. It takes about six months for the manufacturers to formulate and produce the millions of doses required to deal with the seasonal epidemics; occasionally, a new or overlooked strain becomes prominent during that time. It is also possible to get infected just before vaccination and get sick with the strain that the vaccine is supposed to prevent, as the vaccine takes about two weeks to become effective. Yuki: 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. 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, but some strains of influenza can show resistance to the standard antiviral drugs and there is concern about the quality of the research. Stuart: 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. 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, but some strains of influenza can show resistance to the standard antiviral drugs and there is concern about the quality of the research.