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

The Influenza Virus

What the heck is a virus? NOT a bacterium Very, very small Must have living cell (host) to survive and replicate Simple: genetic material wrapped in protein shell

Hemagglutinin Neuraminidase 8 RNA segments Influenza Structure

HHMI movie infection/inf_middle_frames.htm Influenza Replication

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)

The Good Guys: B cells

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

It’s like an Army...

Influenza Can Hide From the Immune System! Influenza alters its spike or knob proteins Memory B cells can’t recognize it anymore old neuraminidasenew neuraminidase new hemagglutininold hemagglutinin

How Influenza Changes Its Surface Proteins Small Changes = Drift

How Influenza Changes Its Surface Proteins Big Changes = Shift

HHMI movie subunit/sub_middle_frames.htm Influenza Reassortment

Prevention and Treatment of Influenza

IMMUNITY Vaccines...Ouch! Immune system responds and is then ready for next infection Expose immune system to a defective virus or viral component

Live virus is injected into fertilized hen’s egg Vaccine Production Virus-containing fluid is harvested from egg Virus replicates as embryo develops

es.html Vaccine Production

Killed Vaccines Also called inactivated vaccines Immune system senses virus, but virus is unable to replicate and spread Virus is killed by injecting a chemical into the egg

Live Vaccines Also called attenuated vaccines Virus is still alive, but can’t cause disease

Live Vaccines Cont’d Virus designed to grow best at colder temperatures Flu virus weakened at body temperature FluMist™ nasal spray (under development)

There must be a better way!!!

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

DNA Vaccines Y Y Y Y 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:

References and Resources OTHER WEBSITES: WEBSITES RELATED TO INFLUENZA CONT’D:

BOOKS: Textbook of Influenza. K. G. Nicholson, R. G. Webster, and A. J. Hay Blackwell Science Ltd., London. The Invisible Enemy: A Natural History of Viruses. D. H. Crawford Oxford University Press, Oxford. The Transmission of Epidemic Influenza. R. E. Hope-Simpson Plenum Press, New York. References and Resources