Tuesday, July 12, 2011

Influenza

Influenza, commonly called the flu is a contagious disease that affects the RNA-containing viruses of the family Orthomyxoviridae (influenza virus), birds and mammals. The most common symptoms are chills, fever, sore throat, muscle aches, severe headache, coughing, weakness / fatigue and general malaise. Although it is often with other influenza-like illness, in particular, confuses the common cold, influenza is a more serious illness than the common cold and is caused by another type of virus. Influenza can lead to nausea and vomiting, especially in children, but these symptoms tend to occur in independent gastroenteritis, which is sometimes inaccurately referred to as "stomach flu". Influenza may from time to time directly or viral pneumonia or secondary bacterial pneumonia.Typically, influenza is transmitted through the air by coughing or sneezing, so the virus aerosols. Influenza can be transmitted by direct contact with nasal secretions or droppings, or through contact with contaminated surfaces. Airborne aerosols have been thought cause most cases of infection, although the mode of transmission is very important, not necessarily clear.Influenza viruses can be inactivated by sunlight, disinfectants and detergents. Since the virus can be inactivated by soap, frequent hand washing reduces the risk of infection.Flu spreads around the world in seasonal epidemics, the death of between & and &  people each year, up to several million in pandemic years. On average 41 400 people die each year in the United States, 1979-2001 influenza. In 2010, the Center for Disease Control and Prevention (CDC) in the United States is changing as reported by the 30-year estimate of deaths. Now they are in the range of about 3,300 low-to high-level 49 000 deaths a year.Three influenza pandemics occurred in the 20th Century, killing tens of millions of people, each of these pandemics caused by the appearance of a new strain of the virus in humans. Often, these new strains emerge when an existing flu virus spreads to humans from other species, or when an existing human strain poses new genes from the virus, which infects birds and pigs in general. Avian flu called H5N1 strain were concerned about a new influenza pandemic, when it emerged in Asia in the 1990s, but it did not lead to a form that can easily develop between people. In April 2009, a new flu virus develops, combination of genes from human, swine and avian influenza, which originally appeared as a "swine flu" and influenza H1N1, as well as in Mexico, announced the United States and other countries. World Health Organization officially a pandemic outbreak on June 11, 2009 (SEE 2009 flu pandemic). WHO pandemic level 6 was directed to disseminate and no difficulties, the burden effectively with lower mortality than normal influenza outbreak.Vaccinations against influenza are usually available for people in developed countries, poultry are often vaccinated to prevent the extermination of the herd. The most common human vaccine is the trivalent influenza vaccine (TIV), which contains purified and inactivated antigens against the three strains of the virus. Typically, this vaccine includes material from two influenza A subtypes and one influenza B virus strain.The TIV carries no risk of disease transmission, and it has very low reactivity. The vaccine can be formulated in a vacuum during the year next year because of the flu virus develops rapidly, and new strains rapidly replace old ones. Antiviral drugs can be used for influenza neuraminidase inhibitors (such as Tamiflu and Relenza) be treated very effectively