Case Study 7-Duel-Use-Lecture-21-Apr

Case Study 7-Duel-Use-Lecture-21-Apr - Case Study 7...

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Case Study 7 Background Also see http://www.pbs.org/wgbh/americanexperience/films/influenza/player/ Influenza, commonly called the “flu”, is a contagious illness caused by one of three types (influenza A, B, and C) of the influenza virus. It is extremely common in the US, and every year 5-20% of the population contracts the flu. Symptoms are generally mild and include fever, headache, coughing, runny nose and muscle aches, however, each year about 36,000 people in the US die from the flu or complications related to the flu. Flu season usually lasts from November until about April or May each year. It is recommended that anyone wishing to avoid contracting the flu be vaccinated, especially those under the age of 5 and over 50, as they are at risk of developing complications from the flu. There are several different subtypes of the influenza A virus. Each is distinguished from the others by variations in the hemagglutinin (HA) and neuraminidase (NA) proteins displayed on the viral surface. Each combination of HA and NA represents a unique subtype, and the only subtypes known to widely circulate between humans are H1N1, H1N2 and H3N2. As a result of selective pressure and the high mutation rate of the virus, there are a number of variants of each influenza subtype. Some variants produce mild disease and transmissibility, while others produce serious disease and are easily passed from person to person. Occasionally a variant of influenza virus can develop that people have little immunity to and also has extremely facile transmissibility. This deadly combination can lead to a global disease outbreak, called a pandemic. The largest pandemic on record occurred in 1918 with the outbreak of the Spanish Flu. Influenza is constantly infecting and interacting with both human and animal hosts. Avian influenza subtype H5N1 is currently causing worldwide concern as it has been able to occasionally infect not only birds but also humans. It is referred to in the media as the “bird flu” and if it develops the ability to spread easily from person to person it could have devastating effects. Beginning in the fall of 1918 and continuing into early 1919 there was a worldwide influenza pandemic. The spread of the so called “Spanish Flu” was accelerated by the close living quarters and travel of soldiers involved in World War I. It is estimated that nearly a third of the world’s population was infected, and between 20 and 50 million people died as a direct result of influenza or of secondary infections like pneumonia. The Spanish flu was unique from any other influenza epidemic in that it was most devastating to otherwise healthy individuals between the ages of 15 and 45. All other flu outbreaks have affected children and the elderly in much higher rates than any other age group. The Spanish flu was characterized by a very aggressive respiratory infection that destroyed lung tissue.
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This note was uploaded on 07/07/2010 for the course BSCU 425 taught by Professor Rollins during the Fall '10 term at Maryland.

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Case Study 7-Duel-Use-Lecture-21-Apr - Case Study 7...

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