Note Sheet 16 - Viruses. Swine (H1N1) Flu Viruses. What is a virus?. Virus – a particle made of a nucleic acid (DNA or RNA) surrounded by protein coat Capsid – the outer coat of protein that covers a virus. Viruses are extremely small – Millions of them could fit into one single cell
Swine (H1N1) Flu Viruses
Percentage of Visits for Influenza-like Illness (ILI) Reported by the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet), National Summary 2008-2009 and Previous Two Seasons (Week ending 11-14-09)
Viruses are NOT made of cells and do not have cell parts
Viruses do NOT take in or use energy
Viruses CANNOT reproduce by themselves
Although there is some argument, most biologists do not consider viruses to be livingIs a virus a living thing?
Vaccine – a weakened or killed virus that is injected into the body so the immune system can recognize the virus and destroy it
Vaccines only work if they are given before an infection – once a viral disease is contracted, it is often too late to control itHow do we defend against viruses?
These epidemics left thousands of children and adults paralyzed
The polio vaccines developed by Jonas Salk in 1952 and Albert Sabin in 1962 are credited with reducing the global number of polio cases per year from many hundreds of thousands to around a thousandVaccine Success Story - Polio