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Learn about the flu, its symptoms, how it spreads, and how vaccines and drugs can help prevent and treat it.
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Who Knew? The Flu and YOU! By: Christine Antler and Erin Boyle
COLD FLU Stuffy or runny nose Sneezing Sore Throat Cough Fever Headache Fatigue, extreme exhaustion, weakness Cough
What the heck is a virus? • NOT a bacterium • Very, very small • Simple: genetic material wrapped in protein shell • Must have living cell (host) to survive and replicate
Hemagglutinin 8 RNA segments Neuraminidase Influenza Structure
Influenza Replication HHMI movie http://www.hhmi.org/grants/lectures/biointeractive/animations/infection/inf_middle_frames.htm
Your Immune System: Under Attack! • Keeps you healthy • Defends your body against invaders • Can sense what’s normal (self), and what isn’t (non-self)
Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y How the immune system targets influenza
Y Y Y Y Y Lights Out for Influenza! MACROPHAGE
Just like an elephant, B cells remember! • Immunity: stronger and faster response
old neuraminidase new neuraminidase old hemagglutinin new hemagglutinin Influenza Can Hide From the Immune System! • Influenza alters its spike or knob proteins • Memory B cells can’t recognize it anymore
How Influenza Changes Its Surface Proteins Small Changes = Drift
How Influenza Changes Its Surface Proteins Big Changes = Shift
Influenza Reassortment HHMI movie http://www.hhmi.org/grants/lectures/biointeractive/animations/subunit/sub_middle_frames.htm
Prevention and Treatment of Influenza Drugs Vaccines
IMMUNITY Vaccines...Ouch! • Expose immune system to a defective virus or viral component • Immune system responds and is then ready for next infection
Vaccine Production Live virus is injected into fertilized hen’s egg Virus replicates as embryo develops Virus-containing fluid is harvested from egg
Vaccine Production http://www.brown.edu/Courses/Bio_160/Projects1999/flu/vaccines.html
Killed Vaccines • Also called inactivated vaccines • Virus is killed by injecting a chemical into the egg • Immune system senses virus, but virus is unable to replicate and spread
Live Vaccines • Also called attenuated vaccines • Virus is still alive, but can’t cause disease
Live Vaccines Cont’d FluMist™ nasal spray (under development) • Virus designed to grow best at colder temperatures • Flu virus weakened at body temperature
Subunit Vaccines • H (spikes) and/or N (knobs) proteins only • Genetic engineering: produce H and N proteins using bacteria or yeast • H and N cause immune response
Y Y Y Y DNA Vaccines H gene (DNA) Inject into human Human cells produce H protein Immune response to H protein
Why do you need to get a new vaccine every year? Influenza alters its H and N all the time!
Drugs Drugs target either H or N and inactivate them
Inhibitors NEURAMINIDASE (N) HEMAGGLUTININ (H) Virus can enter host cells Virus cannot leave host cell Decreased spread of infection Zanamivir and Oseltamivir Virus cannot enter host cells - Decreased infection Amantadine and Rimantadine
Summary • Influenza uses H and N proteins to infect cells • Body develops immunity after fighting off the virus • Influenza changes its H and N to avoid detection • Vaccines trick body into developing immunity • Antiviral drugs inhibit H and N
References and Resources WEBSITES RELATED TO INFLUENZA: http://www.niaid.nih.gov/publications/cold/sick.pdf http://www.med.sc.edu:85/lecture/images/aviron.jpg http://www.asap.unimelb.edu.au/hasn/no32/images/csleggs.jpg http://www.glycoforum.gr.jp/science/word/gif0009/gd-a06e.jpg http://medyred.sureste.com/fotos/influenza.jpg http://www.sciam.com/2001/0201issue/IMG/working_2.gif http://rex.nci.nih.gov/PATIENTS/INFO_TEACHER/immune_sys/Title.html http://www.odomnet.com/vaccines/introduc.htm http://www.uct.ac.za/depts/mmi/stannard/virarch.html http://www.niaid.nih.gov/newsroom/focuson/flu00/background.htm http://www.brown.edu/Courses/Bio_160/Projects1999/flu/vaccines.html http://129.252.124.240:85/mhunt/flu.htm www.accessexcellence.org/AE/AEC/CC/vaccines_how_why_html
References and Resources WEBSITES RELATED TO INFLUENZA CONT’D: http://www.tamiflu.com/ http://www.people.ku.edu/~jbrown/flu.html http://www.people.ku.edu/~jbrown/virus.html http://www.cdc.gov/ncidod/eid/vol4no3/webster.htm http://www.hc-sc.gc.ca/pphb-dgspsp/fluwatch/index.html OTHER WEBSITES: http://www.allenshea.com/gifs/disguise.gif http://www.hemophiliagalaxy.com/1_patients/encyclopedia/images/dna.gif http://pbskids.org/lions/words/images/hen.gi http://www.army.mil/ http://www.oaklandzoo.org/atoz/azeleph.html http://www.leirpoll.com/rubber.htm
References and Resources BOOKS: Textbook of Influenza. K. G. Nicholson, R. G. Webster, and A. J. Hay. 1998. Blackwell Science Ltd., London. The Invisible Enemy: A Natural History of Viruses. D. H. Crawford. 2000. Oxford University Press, Oxford. The Transmission of Epidemic Influenza. R. E. Hope-Simpson. 1992. Plenum Press, New York.