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400 BCE
Hippocrates
Hippocrates was one of the first of the ancient Greek physicians to recognize that illnesses often have environmental causes rather than divine or supernatural origin. Hippocrates was instrumental in establishing the link between early physical symptoms and diseases that came later. By studying the history and symptoms of an illness, Hippocrates recognized that he and other physicians of his time could forecast future disease development - this is epidemiology in its earliest form. -
1300
Bubonic Plague During the Middle Ages
One of the most significant epidemiological events in history was bubonic plague (also known as the Black Death) during the Middle Ages, from around the years 500-1450. The highest number of deaths occurred in Europe from 1346-1352 and wiped out 20-30 million people. Physicians began noticing the correlation of environmental factors (fleas on rats) and later the spread of the disease between the infected and the uninfected. -
Development of Vital Records
Vital records document vital events in a population. These events include births, deaths, marriages, divorces, and fetal deaths. Having records of vital events helps epidemiologists observe health trends that occur in a population across locations and time spans. This data helps epidemiologists to study diseases and environmental influences across populations. John Graunt and William Farr are pioneers in the use of this data that is still significant today. -
Environmental Causes of Disease in Epidemiology
Percivall Pott began to make the correlation between a chronic exposure to soot and a high incidence of scrotal cancer in chimney sweeps. This connection provided not only a clear connection of illness and environment, but also a means to prevent the disease by limiting exposure. The 18th century began an exploration of the risks people faced in their workplaces due to natural and man-made hazardous materials -
Mapping of Cholera
This photograph is a redrawing of John Snow’s original map showing the locations where people died from cholera in the Golden Square area of London in 1854. Dr. John Snow is often referred to as the forerunner of modern epidemiologists. This map was instrumental in the development of description epidemiology, hypothesis generation and hypothesis testing. -
Ethics in Epidemiology
In 1932, the United States Public Health Service began an investigation with the Tuskegee Institute to study the effects of untreated syphilis in African Americans. The study participants never gave informed consent to participate in the study, nor were they offered treatment. This study was a complete moral failure, later leading to the development of ethical research guidelines that were required to be used by epidemiologists. -
Data in Epidemiology
Epidemiologists analyze data to study everything from food-borne illness and infectious diseases to mass shootings and workplace injury -- the scope of study in epidemiology is vast and critical to public health. Data can consist of a vast number of sources, such as vital records, including Census information; Public Health Surveillance Programs, such as care registries for chronic diseases; and data from international organizations, such as the World Health Organization. -
Epidemiological Triangle
One of the most important functions in the field of epidemiology is the investigation of outbreaks of infectious diseases. The epidemiological triangle is a model comprised of an agent, a host, and the environment (external to the host) that is used to describe the etiology of an infectious disease. To illustrate the model, we can use this example: HIV is a viral agent that infects a human host via the environment of blood or other bodily fluids. -
Epidemiology and Public Health Policy
Epidemiology has played an important role in the development of public health policy. Evidence-based decisions founded on epidemiological data have been at the forefront of public health policy in recent decades. Problem definition and formulation/reformulation of solutions to public health dangers by epidemiologists are essential for lawmakers to determine the best possible policies for their communities. -
Current COVID-19 Pandemic in Epidemiology
The epidemiologists at CDC have been intricately involved in almost every aspect of the novel COVID-19 virus since January 2020. The collection of data regarding virulence, risk assessments, community spread, incubation and duration of the illness, developing accurate tests, issuing clinical guidance, and making recommendations for travel restrictions in an effort to contain the spread of the virus are just a few ways that epidemiologists are combating COVID-19.
