Introduction to Infectious Disease Infectious Disease Key Terms

Introduction to Infectious Disease

Infectious Disease – Key Terms • Infectious – can spread • Disease – an abnormal condition affecting the body of an organism • Pathogens – “germs”; what causes disease

Germ Theory through the Ages Germ Theory – states that diseases are caused by microorganisms Before

Before Germ Theory… • Theory of “Spontaneous Generation” – diseases were simply an unfortunate occurrence due to chance & probability Think about it….

Significant Historical Developments in Infectious Disease & Germ Theory

Anton van Leeuwenhoek • First microbiologist; Dutch; 1670 s • Used microscopes to observe and identify microscopic living organisms

Ignaz Semmelweis • Vienna, 1840 s “Childbirth fever”

Louis Pasteur • France, 1859 – Curved Flask Experiment • Essentially the definitive demonstration negating spontaneous generation

Joseph Lister • Lister, 1860 s: Antiseptics • Washed wounds to prevent infections during surgery

Taxonomy and Infectious Disease • What types of pathogens cause infectious diseases? • In what taxonomic kingdoms are they classified?

Taxonomy and Infectious Disease Archaebacteria Prokarya Eubacteria Protista Eukarya Fungi Autotrophic Plantae Animalia

Pathogen 1: Bacteria • Living – Kingdom Eubacteria (although only a small fraction of this kingdom are pathogenic) • Structure Examples – Prokaryotic cells – Produce toxins that harm host (parasitic)

Pathogen 2: Viruses • Non-living!!!! – Infect host and take over cellular metabolism to construct new viruses • Structure: – DNA or RNA core – Contained in protein capsid – Protein spikes to attach to host cells – Some have a membranous envelope – Shape can vary but all viruses are typically symmetrical Examples: HIV, Influenza, Ebola, Chickenpox

Pathogen 3: Fungi • Living – Kingdom Fungi • Structure: – Eukaryotic – Chitin cell wall – Heterotrophic (by absorbing nutrients from host) • Examples: Ringworm, Yeast Infections, Athlete’s Foot

Pathogen 4: Parasites • Living – Kingdoms Protista & Animalia • Structures: – Protozoans – single celled organisms – Helminthes – worms – Animal structures – mosquitoes, fleas, ticks • Transmitted through ingestion of eggs & insect bites • Examples: Malaria, Tapeworm, Bubonic Plague

Pathogen 5: Prions • Non-living • Structure – Misfolded proteins that cause brain and neural damage, eventually fatal • Examples: Mad Cow Disease, Creutzfeldt. Jakob Disease (CJD)

Classroom Activity: “History-Altering” Infectious Diseases 1. Your group will be assigned 1 infectious disease that altered history. 2. Research that disease with your group on www. cdc. gov or other reliable sources about one of the following diseases: • Smallpox in Native American populations during Age of Exploration/Colonialism • Tuberculosis in Industrial Revolution age (“The Great White Plague”), • Bubonic Plague in Europe (“Black Death”) • Cholera in England (England 1800 s), • Yellow fever in the Panama Canal, • Typhus (body lice) during the Thirty Years War • Polio in late 19 th-early 20 th century; • Biology/plant life extension: potato blight (cause of the Irish potato famine), • 1918 influenza in America (“Great Influenza” “Spanish flu” “Flu of 1918”) • H 1 N 1 Bird flu • Swine flu