Introduction to Infectious Disease
Dec 27, 2015
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 AgesGerm 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; 1670s• Used microscopes to observe and identify
microscopic living organisms
Ignaz Semmelweis• Vienna, 1840s
“Childbirth fever”
Louis Pasteur• France, 1859 – Curved Flask Experiment
• Essentially the definitive demonstration negating spontaneous generation
Joseph Lister• Lister, 1860s:
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
Prokarya
Eukarya
Archaebacteria
Eubacteria
Protista
Fungi
Plantae
Animalia
Autotrophic
Pathogen 1: Bacteria• Living
– Kingdom Eubacteria (although only a small fraction of this kingdom are pathogenic)
• Structure– Prokaryotic cells– Produce toxins that harm host (parasitic)
Exam
ples
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 1800s), • Yellow fever in the Panama Canal, • Typhus (body lice) during the Thirty Years War• Polio in late 19th-early 20th century; • Biology/plant life extension: potato blight (cause of the Irish potato famine), • 1918 influenza in America (“Great Influenza” “Spanish flu” “Flu of 1918”)• H1N1 Bird flu• Swine flu