HOW DO VIRUSES CROSS THE SPECIES BARRIER? Rachel Rezabek

How a Virus Works  Viruses cannot survive without a host cell  Provide nutrients and ability to make more viruses  Before a host cell, viruses are in a ‘capsid’ or protein coating  Once in contact with a host cell…  Inserts genetic material to take over all functions  Produces viruses rather than normal products  Happens due to specific shapes (receptors) present on the surface of the virus  Must match the cell for the virus to attach and transfer successfully /intelligent-virus-tricks 11s/human-body/2011/08/a-super-drug-for-a-super- bug.aspx

Virus-Host Interaction  Viruses generally remain within one species  Through certain interaction and mutation, they can jump the species barrier though  Interactions necessary…  Host-host [different species] Different species must be in contact Zoo, farm, wild, etc.  Virus-host Must get past the desired host’s immune system  Host-host [same species] Must interact and pass on the mutated virus nsion.html

Bird Flu  Passed through bodily secretions  Many different subtypes  Dependent on the protein on the surface (HA and NA)  Humans cannot defend against certain variations of these proteins  Not all strains survive today  Some major strains include… H3N8- first known outbreak H5N1- most recent major outbreak (2003)  Many birds have been hunted to help prevent further contact and outbreaks

Swine Flu  Also known as the H1N1 virus  Most common strain  First present in 1918, reappeared in 1977  Killed million people  Originated from pigs  Contact caused mutation that allowed it to spread

Works Cited "Avian Influenza (Flu)." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 21 Nov Web. 17 Jan "Bird Flu - Haemagglutinin." InterPro. The European Bioinformatics Institute, n.d. Web. 11 Jan "Introduction to the Viruses." Introduction to the Viruses. University of California, n.d. Web. 20 Jan "LABORATORY OF VIROLOGY AND INFECTIOUS DISEASE." The Rockefeller University » Laboratory of Virology and Infectious Disease. Rockefeller University, n.d. Web. 25 Jan "Origin of 2009 H1N1 Flu (Swine Flu): Questions and Answers." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 25 Nov Web. 20 Jan