more at http://scitech.quickfound.net/ "Children as carriers and victims of infections." Public domain film from the Prelinger Archive, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied. The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original). http://creativecommons.org/licenses/by-sa/3.0/ http://en.wikipedia.org/wiki/Common_cold The common cold (also known as nasopharyngitis, rhinopharyngitis, acute coryza, or a cold) is a viral infectious disease of the upper respiratory tract which affects primarily the nose. Symptoms include coughing, sore throat, runny nose, sneezing, and fever which usually resolve in seven to ten days, with some symptoms lasting up to three weeks. Well over 200 viruses are implicated in the cause of the common cold; the rhinoviruses are the most common. Upper respiratory tract infections are loosely divided by the areas they affect, with the common cold primarily affecting the nose, the throat (pharyngitis), and the sinuses (sinusitis), occasionally involving either or both eyes via conjunctivitis. Symptoms are mostly due to the body's immune response to the infection rather than to tissue destruction by the viruses themselves. The primary method of prevention is by hand washing with some evidence to support the effectiveness of wearing face masks. The common cold may occasionally lead to pneumonia, either viral pneumonia or secondary bacterial pneumonia. No cure for the common cold exists, but the symptoms can be treated. It is the most frequent infectious disease in humans with the average adult contracting two to three colds a year and the average child contracting between six and twelve. These infections have been with humanity since antiquity... Transmission The common cold virus is typically transmitted via airborne droplets (aerosols), direct contact with infected nasal secretions, or fomites (contaminated objects). Which of these routes is of primary importance has not been determined, however hand-to-hand and hand-to-surface-to-hand contact seems of more importance than transmission via aerosols. The viruses may survive for prolonged periods in the environment (over 18 hours for rhinoviruses) and can be picked up by people's hands and subsequently carried to their eyes or nose where infection occurs. Transmission is common in daycare and at school due to the proximity of many children with little immunity and frequently poor hygiene. These infections are then brought home to other members of the family. There is no evidence that recirculated air during commercial flight is a method of transmission. However, people sitting in proximity appear at greater risk. Rhinovirus-caused colds are most infectious during the first three days of symptoms; they are much less infectious afterwards... http://en.wikipedia.org/wiki/Influenza Influenza, commonly known as "the flu", is an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae, the influenza viruses. The most common symptoms are chills, fever, runny nose, sore throat, muscle pains, headache (often severe), coughing, weakness/fatigue and general discomfort. Although it is often confused with other influenza-like illnesses, especially the common cold, influenza is a more severe disease caused by a different type of virus. Influenza may produce nausea and vomiting, particularly in children, but these symptoms are more common in the unrelated gastroenteritis, which is sometimes inaccurately referred to as "stomach flu" or "24-hour flu". Flu can occasionally lead to pneumonia, either direct viral pneumonia or secondary bacterial pneumonia, even for persons who are usually very healthy... Transmission Influenza virus shedding (the time during which a person might be infectious to another person) begins the day before symptoms appear and virus is then released for between 5 to 7 days... 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 hand-shake... As the influenza virus can persist outside of the body, it can also be transmitted by contaminated surfaces such as banknotes, doorknobs, light switches and other household items...

• published: 25 Jun 2013
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