Topic 2 - The History and Scope of Epidemiology Flashcards

Question

What is an epidemic?

Answer 1

The occurrence in a community or region of cases of an illness (or an outbreak) clearly in excess of normal expectancy… Relative to usual frequency of the disease

Answer 2

Communicable disease: an illness caused by an infectious agent that can be transmitted from one person to another Infectious disease: a synonym for a communicable disease Outbreak: a localized disease epidemic, e.g., in a town or health care facility

Answer 3

An epidemic on a worldwide scale; during a pandemic, large numbers of persons may be affected and a disease may cross international borders.” Example: flu pandemic Endemic: to characterize a disease that is habitually present in a particular geographical region

Answer 4

Surveillance and epidemic threshold

Answer 5

The systematic collection of data pertaining to the occurrence of specific diseases Analysis and interpretation of these data Dissemination of disease-related information Common activities include monitoring food born disease outbreaks and tracking influenza

Answer 6

The minimum number of cases (or deaths) that would support the conclusion that an epidemic was underway This is based on statistical projections

Answer 7

John Graunt: summarized the pattern of mortality in 17th century London William Farr: compiled data on births, deaths etc. as ratios in the 19th century John Snow: showed that cholera was transmitted by fecal contamination of drinking water in the 19th century

Answer 8

Hippocrates wrote On Airs, Waters, and Places in 400 BC He suggested that disease might be associated with the physical environment This represented a movement away from supernatural explanations of disease causation

Answer 9

London tradesman (1620 – 1674) Founded the Royal Society of London Laws of mortality (17th century): disease and death is not random; a pattern may exist First epidemiologist, analyzed weekly counts of deaths in London Created the Bills of Mortality

Answer 10

1662: published Natural and Political Observations Made upon the Bills of Mortality. He is credited with being first to use statistics for understanding disease

Answer 11

Recorded seasonal variations in births and deaths Showed excess male over female differences in mortality Known as the “Columbus” of biostatistics

Answer 12

Jenner conducted an experiment to create a smallpox vaccine He developed a method for smallpox vaccination In 1978 smallpox was finally eliminated worldwide Since 1972, routine vaccination of the nonmilitary population of the U.S. has been discontinued In the eighteenth century, smallpox was a widespread major killer. The majority of smallpox victims were infants and young children It had been observed that milkmaids who developed cowpox, a disease similar to but less severe than smallpox, did not get smallpox Jenner, an English physician, experimented with inoculating healthy people with material from cowpox lesions. Those who developed cowpox were immune to smallpox. His work led to the discovery of an effective smallpox vaccine in the 1790s

Answer 13

John Snow was an English physician and anesthesiologist He investigated a cholera outbreak that occurred during the mid-19th century in Broad Street, Golden Square, London

Answer 14

Naturally occurring circumstances in which subsets of the population have different levels of exposure to a supposed causal factor in a situation resembling an actual experiment, where human subjects would be randomly allocated to groups. The presence of persons in a particular group is typically nonrandom

Answer 15

John Snow, London physician & student of William Farr, achieved prominence as an obstetrician who was also a pioneer in use of anesthesia. His work in epidemiology, however, is his greatest legacy. He is sometimes called the “father of epidemiology” Snow conducted careful investigations of cholera epidemics in London during the mid-1800’s. Cholera is a bacterial infection that causes severe diarrhea & dehydration. Severe untreated cases can have a mortality of over 50%. With current treatment methods, mortality is less than 1% Snow believed that cholera was transmitted through the water, not a generally accepted belief. Most believed the miasma theory (including Farr, as mentioned above), which proposed spread through the air. In 1854, during a major cholera outbreak in London, he made a map showing the locations of public water pumps as well as the locations of cholera deaths. Snow noted that most deaths were occurring in the areas served by the Broad Street Pump. Although not conclusive, there is some evidence that Snow removed the Broad Street Pump handle, causing the cholera epidemic to cease Snow’s study of two different water companies that provided water to London provided excellent evidence that cholera was transmitted by water The Lambeth got water from above where London sewage emptied into the Thames while the Southwark & Vauxhall obtained water from below where sewage entered. Cholera death rates were much greater for Southwark & Vauxhall (sewage-contaminated water) than for Lambeth districts. In districts provided water by both companies, Snow determined which company provided the water for a house & the number of cholera deaths in that house

Answer 16

Linked the cholera epidemic to contaminated water supplies Used a spot map of cases and tabulation of fatal attacks and deaths

Answer 17

Two different water companies supplied water from the Thames River to houses in the same area The Lambeth Company moved its source of water to a less polluted portion of the river Snow noted that during the next cholera outbreak those served by the Lambeth Company had fewer cases of cholera

Answer 18

Mid-19th century, Viennese hospital Clinical assistant in obstetrics and gynecology Observed higher mortality rate among the women on the teaching wards for medical students and physicians than on the teaching wards for midwives Postulated that medical students and physicians had contaminated their hands during autopsies Introduced the practice of hand washing

Answer 19

British Epidemiologist (1837-1841) Founder of modern epidemiology Compiled annual counts of births, deaths etc. (vital records) Compiled data as ratios; counts (numerator) and census data (denominator) Appointed compiler of abstracts in England, 1839 Provided foundation for classification of diseases (ICD system) Used data such as census reports to study occupational mortality in England Examined linkage between mortality rates and population density Beginning in the mid-1800s, Farr built on the work of Graunt by systematically collecting and analyzing Britain’s mortality statistics. This established the field of vital statistics Farr is considered the father of modern vital statistics (birth & death records) and surveillance Promoted the idea that some diseases (especially chronic) may have a multifactorial etiology

Answer 20

Koch & Louis Pasteur established the germ theory of disease. Koch took the first pictures of microbes and demonstrated that microorganisms do exist and cause diseases Koch showed that anthrax was transmissible and reproducible in experimental animals (mice) and that the anthrax bacillus was the only organism that caused anthrax in a susceptible animal Microorganism must be observed in every case of the disease Microorganism must be isolated and grown in pure culture Pure culture must, when inoculated into a susceptible animal, reproduce the disease Microorganism must be observed in, and recovered from, diseased animal

Answer 21

Alexander Fleming discovered the antimicrobial properties of mold: led to the discovery of the antibiotic penicillin Alexander Langmuir established CDC’s Epidemic Intelligence Service; Father of infectious disease epidemiology Wade Hampton Frost was the first professor of epidemiology in the U.S. Joseph Goldberger discovered the cure for pellagra

Answer 22

The Framingham Heart Study (ongoing since 1948) investigates coronary heart disease risk factors Smoking and lung cancer; e.g., Doll and Peto’s study of British doctors’ smoking AIDS, chemical spills, breast cancer screening, second-hand cigarette smoke Infectious diseases: SARS, pandemic influenza 2009 H1N1, Avian influenza Environmental health Chronic diseases, lifestyle and health promotion Psychological and social epidemiology