1. INFLUENZA LUKE UYEMURA ENGLISH 100 ESP

2. BASIC INFO Definition: Influenza, more commonly know as the flu, is a viral infection that attacks your respiratory system — your nose, throat and lungs. Symptoms: Fever over 100 F (38 C) Aching muscles, especially in your back, arms and legs Chills and sweats Headache Dry, persistent cough Fatigue and weakness Nasal congestion Sore throat Risk Factor: Young children under 5, and especially those under 2 years Adults older than 65 Residents of nursing homes and other long-term care facilities Pregnant women People with weakened immune systems People who have chronic illnesses, such as asthma, heart disease, kidney disease and diabetes People who are very obese, with a body mass index (BMI) of 40 or higher http://www.mayoclinic.org/diseases-conditions/flu/basics/definition/con-20035101

3. FOUR MAJOR PANDEMICS: Spanish Flu (1918-1919) The Spanish Flu from 1918 spread rapidly taking victim of healthy adults, some who “felt fine in the morning but died by nightfall.” Those who caught the virus but didn’t die, often died from complications caused by bacteria, such as pneumonia. Asian Flu (1957-1958) First identified in the far east. The pandemic was predicted and prepared for by production of a limited supply of the vaccine, but the virus quickly and quietly through classrooms to homes. After the pandemic seemed to have died down a second wave hit early 1958. Hong Kong Flu (1968-1969) The Hong Kong flu is said to be the “mildest” of the pandemics in the 20 th century. Hit when children were on vacation decreasing the infection rate. Increased medical care at the time also helped combat the virus. Swine Flu (2009-2010) Also know as the H1N1 virus, it spread very quickly across the U.S. and the world. First diagnosed on April 15, 2009 and announced a public health emergency by the 26 th. By June a total of 74 countries were affected by the pandemic. The CDC estimates that 43 million to 89 million people had H1N1 between April 2009 and April 2010. The end of the global pandemic was declared on August 2010. http://www.flu.gov/pandemic/history/

4. CLASSIFICATION There are three types of the Influenza virus: A, B, and C Type A viruses are divided into subtypes based on two proteins on the surface of the virus: the hemagglutinin (H) and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes. (H1 through H18 and N1 through N11 respectively.) Type B viruses are not divided into subtypes, but can be further broken down into lineages and strains. Currently circulating influenza B viruses belong to one of two lineages: B/Yamagata and B/Victoria. Type C infections cause a mild respiratory illness and are not thought to cause epidemics. http://www.cdc.gov/flu/about/viruses/types.htm

5. ANTIGENIC SHIFT Antigenic Shift is defined as the genetic change that enables a flu strain to jump from one animal species to another, including humans. Antigenic shift can happen in three ways: Antigenic Shift 1 A duck or other aquatic bird passes a bird strain of influenza A to an intermediate host such as a chicken or pig. A person passes a human strain of influenza A to the same chicken or pig. When the viruses infect the same cell, the genes from the bird strain mix with genes from the human strain to yield a new strain. The new strain can spread from the intermediate host to humans. Antigenic Shift 2 Without undergoing genetic change, a bird strain of influenza A can jump directly from a duck or other aquatic bird to humans. Antigenic Shift 3 Without undergoing genetic change, a bird strain of influenza A can jump directly from a duck or other aquatic bird to an intermediate animal host and then to humans. http://www.niaid.nih.gov/topics/flu/research/basic/pages/antigenicshiftillustration.aspx

6. KEY TERMS Epidemic Pandemic Antigenic shift Hemagglutinin Neuraminidase Vaccination Subtype Strain Transmission Nomenclature

7. CRITICAL QUESTIONS What other outbreaks of the flu were considered major outbreaks but not full on pandemics? How effective are the vaccines we uses today in fighting the current influenza virus? What other ways could the influenza virus mutate to challenge our methods to fight it?