IN QUESTION: COPY & COMPLETE IN YOUR ISN… 1.Why has the “Flu” recently become a nationwide epidemic? 2.Explain your answer.

NOTES: Intro. Epidemiology & Infectious Diseases Use this class set of notes to help you answer the PPT Review Questions on the next slide.

Copy & Answer on Paper to turn-in for a grade. Intro. Epidemiology & Diseases PPT Review Questions Copy & Answer on Paper to turn-in for a grade. 1.What is Epidemiology? Why should we study it? 2.How did the following scientists impact the history of epidemiology: Hippocrates? John Graunt? William Farr? John Snow? 3.List 6 health assessment questions used in epidemiology. 4.What is a case definition used for? 5.Who does a physician send reportable diseases to? 6.What 3 types of information is sent by physicians?

PPT Review Questions (cont’d) 7.How do health departments convert case counts into rates? 8.How does descriptive epidemiology organize and summarize data? 9.How is time data shown in descriptive epidemiology? 10.Why is a “place” used in descriptive epidemiology? 11.Give 3 examples of “places” used. 12.Give 2 examples each of the following about people: Inherent Characteristics? Acquired ? Activities? Conditions? 13.Why is Analytic Epidemiology used?

PPT Review Questions (cont’d) 14.What is the purpose of experimental epidemiology? Observational epidemiology? 15.Describe 2 types of observational studies. 16.What is meant by “cause” of disease? 17.Draw & Label the “Epidemiologic Triangle” 18.Define the following terms: Agent? Host Factors? Environmental Factors? 19.Draw & Label the Chain of infection diagram. 20.What is a reservoir? Portal of Exit? Portal of Entry? Host?

PPT Review Questions (cont’d) 21.Name & Describe 3 Modes of Transmission. 22.Define level of disease. 23.Draw & Label the Epidemic Disease Ocurance Chart. 24.What is meant by sporadic? Endemic? Epidemic/Outbreak? Hot Zone? Pandemic? 25.How might charts, graphs, and maps be used in epidemiology? Explain why. REMEMBER TO TURN-IN THESE QUESTIONS & ANSWERS FOR A GRADE TODAY

Epidemiology

Comes from Greek words epi, meaning “on or upon” demos,meaning “people” logos, meaning “the study of” Study of distribution and determinants of health-related conditions or events in populations

History Hippocrates (circa 400 B.C.) attempted to explain disease occurrence from a rational instead of a supernatural viewpoint

John Graunt, a London haberdasher, published his landmark analysis of mortality data in He was the first to quantify patterns of birth, death, and disease occurrence, noting male-female disparities, high infant mortality, and seasonal variations

Mid 1800’s William Farr began to systematically collect and analyze Britain’s mortality statistics. John Snow, an anesthesiologist, conducted a series of investigations in London that later earned him the title “the father of epidemiology.”

Discipline did not flourish until the end of the Second World War

Uses

Population or community health assessment What are the actual and potential health problems in the community? Where are they? Who is at risk? Which problems are declining over time? Which ones are increasing or have the potential to increase? How do these patterns relate to the level and distribution of services available?

The Epidemiologic Approach Case Definition – a set of standard criteria for deciding whether a person has a particular disease or other health- related condition.

Statistics and Reports When physicians diagnose a case of a reportable disease they send a report of the case to their local health department. Time - when the case occurred place - where the patient lived person - the age, race, and sex of the patient

Health departments convert the case counts into rates, which relate the number of cases to the size of the population where they occurred

Types of Epidemiology

Descriptive Epidemiology Organize and summarize data according to time, place, and person Time – disease rates change over time – the seasonal increase in influenza with the onset of cold weather Time data is usually shown on a graph

Place - describe a health event by place to gain insight into the geographical extent of the problem. Residence Birthplace Place of employment School district Hospital unit, etc

Person Inherent characteristics of people Age Race Sex

Acquired Characteristics Immunity Marital status

Activities Occupation Leisure activities Use of medications/tobacco/drugs

Conditions under which people live Socioeconomic status Access to medical care

Analytic Epidemiology Used to search for causes and effects, or the why and the how.

Experimental Determine the exposure status for each individual (clinical trial) or community (community trial); we then follow the individuals or communities to detect the effects of the exposure

Observational Observe the exposure and outcome status of each study participant Cohort study - categorize subjects on the basis of their exposure and then observe them to see if they develop the health conditions being studied Case-control study - enroll a group of people with disease (“cases”) and a group without disease (“controls”) and compare their patterns of previous exposures

Causation

Cause of disease is a factor (characteristic, behavior, event, etc.) that influences the occurrence of disease An increase in the factors leads to an increase in disease. Reduction of the factors leads to a reduction in disease

Epidemiologic Triangle Traditional model of infectious disease causation.AgentHost Environment

Agent Infectious microorganism - must be present for disease to occur Virus Bacterium Parasite Other microbeAgentHost Environment

Host Factors Intrinsic factors that influence an individual’s exposure, susceptibility, or response to a causative agent. Age Race Sex Socioeconomic status BehaviorsAgentHost Environment

Environmental Factors Extrinsic factors which affect the agent and the opportunity for exposure Physical factors Biologic factors Socioeconomic factorsAgentHost Environment

Epidemiology and Disease

Chain of Infection Reservoir Mode of Transmission SusceptibleHost Transmission

Chain of Infection Reservoir of an agent is the habitat in which an infectious agent normally lives, grows, and multiplies. Portal of exit is the path by which an agent leaves the source host

Chain of Infection Modes of transmission Direct – immediate transfer of the agent from a reservoir to a susceptible host by direct contact or droplet spread Direct contact Droplet spread Indirect – an agent is carried from a reservoir to a susceptible host by suspended air particles or by animate (vector) or inanimate (vehicle) intermediaries Airborne Vehicleborne Vectorborne Mechanical Biologic

Chain of Infection Portal of entry – means by which an agent enters a susceptible host Host – individual infected with the agent

Epidemic Disease Occurrence Level of Disease - amount of a particular disease that is usually present in a community Sporadic Endemic Epidemic Pandemic Increasing amount of disease

Sporadic - irregular pattern of occurrence, with occasional cases occurring at irregular intervals

Endemic - persistent level of occurrence with a low to moderate disease level

Epidemic or Outbreak- occurrence of a disease within an area is clearly in excess of the expected level for a given time period Hot Zone – area where outbreak occurs

Pandemic - an epidemic spreads over several countries or continents, affecting a large number of people

Activity: Interview Question 1. Copy the Chart & Question from the next slide on paper. 2. Ask 10 classmates the question and record their age & response on the chart.

Persons # 1-10 AgeEpidemicPandemicAdditional Comments When people of different age groups hear the word “epidemic” or “pandemic”, what disease comes to mind?

EXIT TICKET: Begin H.W. p.62 “Types of Immunity” (Read & Color) Study for Quiz: Intro. Patho & Immunology Next Class