Lecture1b_PH162A_20240829.pdf

INTRODUCTION TO PUBLIC HEALTH MICROBIOLOGY Ashley Wolf, PhD PH162A August 29, 2024  Introduce yourself to a neighbor Name Class year, major Why you’re taking this class Something unexpected that happened to you this summer...

INTRODUCTION TO PUBLIC HEALTH MICROBIOLOGY Ashley Wolf, PhD PH162A August 29, 2024  Introduce yourself to a neighbor Name Class year, major Why you’re taking this class Something unexpected that happened to you this summer Iclicker short answer question  Overview What is public health? Overview of types of microbes Class survey Loading… Overview of microbiology history Iclicker short answer question  What is public health? Public health is the science of protecting and improving the health of populations: from neighborhoods to cities to countries to world regions Through: Education Promotion of healthy lifestyles Research toward prevention of disease and injury Detecting, preventing, and responding to infectious diseases https://www.hsph.harvard.edu/communications-guide/what-is-public-health/  What are careers in public health microbiology? Scientists and researchers Epidemiologists Policymakers Nurses Loading… Health educators Physicians Restaurant inspectors https://www.hsph.harvard.edu/communications-guide/what-is-public-health/  What do public health professionals do? Develop plans and strategies to respond to outbreaks Test biological and environmental samples Monitor air and water quality Implement vaccine programs Improve care for pregnant women, mothers and children Investigate infectious disease outbreaks Analyze, design and implement public health policy https://www.hsph.harvard.edu/communications-guide/what-is-public-health/ What is the first microbe that comes to mind? Iclicker short answer question What size are microbes?  Microbe- centric Tree of Life Jill Banfield Lab, 2016 Prokaryotic Microbes Prokaryotes are: – Single-celled – Lack a nucleus – Lack membrane-bound organelles Fu Bacteria – Include pathogenic species – Many shapes Archaea not pathogenic – Environmental extremophiles – Novel biochemistry – Not pathogens to humans John Wiley & Sons / McGraw Hi Eukaryotic Microbes Eukaryotes – Contain nucleus and membrane-bound organelles Algae (Protozoa/Plants) – Photosynthetic – Most single-celled, some multicellular Loading… – Important source of food – Aquatic – Only one species causes disease in humans Fungi (Kingdom) – Decomposers – Single or multicellular – Can be pathogens Copyright © 2018 by John Wiley & Sons, Inc. All rights reserved Eukaryotic Parasites Protozoa (Kingdom) – Single celled – Engulf food – Most have motility – May be pathogenic Helminths (Worms) Amoeba – Microscopic life stages – Diagnosed microscopically Arthropods (insects) – Cause/transmit disease Tapeworm Copyright © 2018 by John Wiley & Sons, Inc. All rights reserved Acellular Infectious Agents Agent Characteristic Viruses DNA or RNA protein coat Obligate intracellular agents Use the machinery and nutrients of host cells to replicate. Viroids RNA no protein coat Obligate intracellular agents Use the machinery and nutrients of host cells to replicate. Prions Only protein Misfolded versions of normal cellular proteins that cause the normal versions to misfold. Wiley & Sons, Inc / McGraw Hi THE HISTORY OF PUBLIC HEALTH MICROBIOLOGY Pre-microbiology understanding of disease Transmission of diseases like leprosy led to isolation of affected patients (recorded in the Bible) Greeks and Romans believed disease was caused by bad air or “miasmatic odors” Rome’s advanced aqueduct and sewer system likely prevented water-borne outbreaks https://open.oregonstate.education/microbiology/chapter/1-1-what-our-ancestors-knew/ Pre-microbiology understanding of disease Hippocrates (460–370 BCE): dismissed supernatural theory of disease and proposed that disease was caused by within patients or came from environment Thucydides (460–395 BCE): observed that survivors did not get re-infected with the disease, even when taking care of actively sick people Marcus Terentius Varro (116–27 BCE): proposed the concept that things we cannot see can cause disease https://open.oregonstate.education/microbiology/chapter/1-1-what-our-ancestors-knew/ Bubonic plague Y. Pestis found in ancient DNA from 5000 years ago National Library of Medicine / https://asm.org/articles/2022/january/genomic-sequencing-of-ancient-dna-illuminates-plag McGraw Hi  300X ≈1670-1720 microscope built. VAN LEEUWENHOEK DISCOVERS MICROORGANISMS A Dutch draper who made small microscopes No formal education, but insatiable curiosity The first to visualize bacteria, protozoans, fungi, and algae 185 4 THE BIRTH OF EPIDEMIOLOGY John Snow mapped where the cases of cholera in London were occurring during the Broad Street epidemic C.H. Cheffins https://blog.rtwilson.com/john-snows-cholera-data-in-more-formats/ 1847- 1867 ERA OF SANITATION BEGINS Antiseptic surgery and improved hygiene in hospitals Pasteurization of milk Sewage treatment and water purification Germ Theory of Disease Microorganisms (germs) can invade other organisms and cause disease Not widely accepted when put forth in mid- nineteenth century Many believed in abiogenesis & spontaneous generation – Microorganisms arose from nonliving things Copyright © 2018 by John Wiley & Sons, Inc. All rights reserved Spontaneous Generation versus Biogenesis Francesco Redi (1668) – Gauze covered glass jar with meat – Proved maggots did not arise spontaneously, but required egg laying Copyright © 2018 by John Wiley & Sons, Inc. All rights reserved Spontaneous Generation versus Biogenesis Louis Pasteur, 1859 McGraw Hi  Isolating and culturing microbes Solid culture was needed to isolate individual colonies Petri dishes with gelatin would melt or get eaten by bacteria and and ruin experiments Angelina Fanny Hesse recommended agar, which was used to make soups, desserts and jellies in Asia Agar can’t be digested by most bacteria This method of growing bacteria enabled identification of pure colonies and is still in use today Copyright © 2018 by John Wiley & Sons, Inc. All rights reserved Koch’s Postulates Robert Koch – Late 1800’s – First to identify bacterium that causes anthrax – Studies on tuberculosis won him the Nobel prize https://microbenotes.com/kochs-postulates-and-its-limitations/ Copyright © 2018 by John Wiley & Sons, Inc. All rights reserved  The primary use of Koch's postulates is to: A. clearly identify and characterize a particular microorganism. B. Isolate microorganisms from diseased animals & C. Demonstrate that a disease is caused by a microorganism D. Develop vaccines for specific diseases Iclicker multiple choice question 1901- ≈1965 ERA OF ESTABLISHING ETIOLOGY OF VIRAL DISEASES BEGINS Immunological postulates formulated and applied Viral agents of many diseases identified – Yellow fever, dengue fever – Poliomyelitis, chickenpox – Measles, mumps, rubella – Rabies – Infectious mononucleosis 1897 7ERA OF VECTOR CONTROL BEGINS Mosquitoes proven to transmit infectious microorganisms Loading… Vector control measures carried out – Swamp drainage – Insecticides ≈1890-1954 ERA OF VACCINES BEGINS Smallpox vaccination -give mild smallpox – Originated by Chinese ≈1000 A.D. – Introduced into Europe by Lady Montagu (1717) after observing in Constantinople (now Istanbul) – Refined by Jenner (1797) Gusecowpox Development of first toxoid, killed whole organism, and live attenuated vaccines – diphtheria – tetanus – whooping cough – polio Global outbreaks McGraw Hi 2014 Death Toll in Ebola Virus Outbreak Reaches 932 health.harvard.edu 2016 Is the Zika Virus now an epidemic in this country?  2019: The SARS-CoV-2 Pandemic Large family of enveloped +ssRNA viruses Viral particles encircled in surface proteins that interact with host cell receptors Frequent cause of respiratory infections in humans and other species https://en.wikipedia.org/wiki/Coronaviridae  Transmission Coronaviruses are zoonotic, and can therefore be transmitted between animals and humans Human-to-Human transmission primarily occurs via close contact with https://www.who.int/health-topics/coronavirus https://www.cdc.gov/onehealth/basics/zoonotic-diseases.html respiratory droplets generated by What topic are you most interested to learn about? Iclicker short answer question Class survey https://forms.gle/NgyLiuqqWQJo6THT6