Epidemiology is a branch of medical science that studies and analyzes the patterns, distribution, causes, and effects of human populations’ diseases. The word is the combination of three Greek words: epi meaning upon or among; demos refers to people; and logos is a common suffix in the form of ology used in the sciences that means study or word. Therefore, a literal translation is – the study of what is among or upon the people.
Hippocrates (460 BCE-370 BCE), the Greek physician, has received credit for first using the words endemic and epidemic. The former are diseases specific to a particular area or region. The latter refers to diseases that occur at a specific time, as in a flu epidemic. Another word all too familiar to all of us – pandemic. Turning to Greek, the prefix of pan means all, and the demic suffix is again: the people. Hence a pandemic is a health-related event or illness that infects humans across a large geographical like the current global COVID-19.
Epidemiology involves the investigation of the factors that influence the presence and absence of diseases and disorders. Through quantitative analysis, scientists learn to understand how many are infected or suffer from the illness in question. They also examine whether the numbers are changing and their impact on society.
The pandemic of 2020-21, the coronavirus or COVID-19, has had 103,486,647 cases worldwide as of February 2, 2021, and 2,240,276 deaths. As of this date, there are 20,231,186 infected patients, according to Worldometers. These figures pale in comparison to the pandemic of 1918, mislabeled the Spanish Flu. Exact statistics are unknown; however, the Centers for Disease Control and Prevention (CDC) estimated that 50 million died or one-third of the world’s population in 1919.
Epidemiologists opine that the lack of hygiene, modern medical equipment, and vaccines attributed to the catastrophic number of deaths.
The study of epidemiology need not require a medical degree. A master’s or doctorate is essential to a career in the field. One subject crucial to this science is statistics. As mentioned, to evaluate the pervasive nature of a disease, you will have to analyze data. How many infections? What is the rate of increase in new cases? How widespread is the condition? From the latter, the scientist or public health officials may determine how and where the illness originated.
In 1976 in Philadelphia, local health authorities, the CDC, medical personnel, and epidemiologists had the task of ascertaining the origin of the coincidental deaths of three men who attended a convention at the Bellevue-Stratton Hotel. Five attendees died within three days of leaving the hotel on July 27, 1976. By August 1, six more died who attended the American Legion annual convention. The final tally was 211 cases and 29 deaths associated with the hotel.
In January 1977, the investigators concluded that Legionnaires’ disease originated in bacteria breeding in the hotel’s air conditioning system. They called the bacterium Legionella after the first victims.
The study plan to become an epidemiologist is the topic of another DegreeQuery post. To touch on it briefly, you can earn a master of science in the discipline without an extensive science class list. Unlike a pathologist, bacteriologist, or infectious disease doctor, epidemiology focuses on the questions posed above. Namely, why is an individual illness affecting people in a specific area? They try to determine a common element for those displaying the same or similar symptoms. Professionals in this field may predict annual flu season cases, malaria, tuberculosis, or allergic conditions.
In the case of Legionnaires’ disease, it is one step for the medical scientists to find the causative agent (bacteria), and the epidemiologist’s job to understand how the host and the environment collaborated in causing the resulting infection.
Since the advent of computers and medical advances, epidemiology has expanded to include studying and analyzing reams of electronic data from genomics, clinical, and molecular studies. (A genome is an organism’s set of DNA). This science is paramount in today’s public health system and preventative medicine. It has incorporated the study of environmental factors, like pollution, and fertility, and infant mortality rates in a given population.
In public health, awareness, influenced by behavior and biology, affects behavior conducive to improved community health. The study of epidemiology plays a vital part in ensuring the welfare of citizens.