Examples to understand 

What is Epidemiology?

Source: CDC
Dr Fauci and Pres. Trump

In the WH historic Covid 19 Pandemic photo above, we can ask:

  1. Who is doing the Talking?

  2. Who KNOWS about Epidemiology?

  3. Why is the President taking center stage?

  4. Has the US President demonstrated interest and knowledge of Epidemiology?

  5. Is drinking Lysol as he considered a cure for Covid 19.

  6. Is the CDC - the experts - in charge?


What is Epidemiology?

Black death flea

The Origins of the Black Death - Oriental rat flea 


Epidemiology is the method used to find the causes of health outcomes and diseases in populations. In epidemiology, the patient is the community and individuals are viewed collectively.

Black plague symptoms


By definition, epidemiology is the study (scientific, systematic, and data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (neighborhood, school, city, state, country, global).

It is also the application of this study to the control of health problems (Source: Principles of Epidemiology, 3rd Edition).


What public health problems or events are investigated?

Environmental exposures
  • Lead and heavy metals
  • Air pollutants and other asthma triggers
Infectious diseases
  • Foodborne illness
  • Influenza and pneumonia
  • Increased homicides in a community
  • National surge in domestic violence
Non-infectious diseases
  • Localized or widespread rise in a particular type of cancer
  • Increase in a major birth defect
Natural disasters
  • Hurricanes Katrina and Rita (2005)
  • Haiti earthquake (2010)
  • World Trade Center (2001)
  • Anthrax release (2001)