History of viruses Viruses have been around for a long time, but only recently have we gained the ability to investigate what they look like.

History of Viruses Understanding Viruses

History of Viruses Edward Jenner (1798) Infected patients with cowpox (Vaccinia) virus, giving them immunity to smallpox = first vaccine Smallpox has been eradicated from the world today. 3

History of Viruses Dmitri Ivanovsky (1892) Showed that the infectious agent that causes Tobacco Mosaic Disease could pass through filters known to stop bacteria. 4

History of Viruses “Spanish flu” pandemic (1892) Extremely virulent form of the flu that killed an estimated 20 – 50 million people around the world. 5

History of Viruses 1930s Development of the electron microscope provides allows scientists to view microscopic objects at extreme magnification. 6

Tobacco Mosaic Virus Wendell Stanley (1935) discovered viruses were made of nucleic acid and protein 7

History of Viruses Development and use of the Salk (killed) and Sabin (live) polio vaccines in the US 8

History of Viruses 1976 Outbreak of hemorrhagic fever in Sudan and Zaire. Virus is named after the Ebola River, where the first cases were believed to originate. 9

History of Viruses Early 1980s AIDS is recognized as a new human disease caused by a retrovirus known as HIV. 10

History of Viruses “Swine flu” pandemic (2009) A new H1N1 influenza virus of swine origin begins infecting people in Mexico before spreading to over 200 countries around the world. 11

Herpes Virus (DNA) Herpes Virus (DNA) 12 SIMPLEX I and II

Rhinovirus (RNA) Rhinovirus (RNA) 13 COMMON COLD

Influenza Virus (RNA) 14

Chickenpox Virus (DNA) 15

Papillomavirus – Warts! (DNA) 16

HIV – (Retrovirus) 17

HOST SPECIFICITY All kingdoms can be infected by viruses Viruses are kingdom specific but they may or may not be species specific Spread is specific to the type of virus

PARASITISM Viruses are parasites. – A parasite is an organism that depends upon another living organism for its existence in such a way that it harms that organism.

Vaccine Is most often a weakened or inactivated form of the virus – To expose your immune system to the virus which will allow your body to better fight off the more virulent form of the virus if your body is exposed to it again in the future.

Vector Control This is controlling the vectors that are carrying the virus. Examples: – We stay home when sick, cover our mouth when we cough etc. – We control the mosquito population in order to control the West Nile virus

Other Drug Treatments Specific to certain viruses. They don’t cure the virus but they can slow down and inhibit the multiplication of the virus. copyright cmassengale 22

Reducing the Risk Most viruses can’t be treated, but they can be prevented! Cover mouth/nose when you sneeze of cough Wash hands frequently Avoid contact with the body fluids Not foolproof but reduces the risks