The following is an example of an epidemiologic triad.

  • Agent: the salmonella organism
  • Keep in mind that agents can be biologic (e.g., bacteria or viruses), chemical (e.g., poisons or alcohol), physical (e.g., trauma or radiation), or nutritional (e.g., a lack or excess of essential nutrients).
  • Host factors: individuals who are particularly vulnerable (e.g., the very young or very old and immunocompromised individuals)
  • Note that, in general, host characteristics can include age, sex, race, religion, customs, occupation, genetic factors, other health factors, and immunologic status.
  • Environmental factors: contaminated kitchen surfaces or utensils, undercooking of contaminated food items, or contaminated chicken
  • Environmental factors can include temperature, crowding, noise, pollution, food, and radiation.

Changes in one factor in the epidemiological triad can influence the occurrence of disease by increasing or decreasing a person’s risk for disease. Consider how variations in each factor shown in the example can influence the manifestation of disease. Refer to pages 438–445 in your textbook for further explanation.

In this Discussion, you will provide other examples of the epidemiological triad and discuss them with your colleagues.

To prepare for this Discussion:

To complete the Discussion, post the name of the disease you selected. Next, apply the disease to the epidemiologic triad. Provide an example of an agent that is associated with the disease you selected. Provide at least three examples of environmental factors and three examples of host factors that contribute to the likelihood of transmission of that agent to an individual.




Friis, R., & Sellers, T. (2014). Epidemiology for public health practice (5th ed.). Burlington, MA: Jones & Bartlett.
Chapter 1, “History and Scope of Epidemiology”This chapter provides definitions of epidemiological concepts. In addition, it gives a brief introduction to the interdisciplinary approach of epidemiology, including an overview of the history of the field. It includes a number of case studies that illustrate the key points of the chapter.
Chapter 2, “Practical Applications of Epidemiology” (pp. 55–83; 98–101)Building upon the historical events that characterize the study of epidemiology, this chapter discusses the major applications of epidemiology in public health, clinical, and operational settings. The different types of prevention are also discussed.
Chapter 12, “Epidemiology of Infectious Diseases”This chapter explores the modes of transmission of infectious agents. In addition, the categories of infectious disease agents and their characteristics are presented. Aspects of investigating disease outbreaks are also explained.

What is Epidemiology?
This presentation provides a general overview of the field of epidemiology. It also serves as a summary of the topics that will be presented in this course. 

Required Media

Is Epidemiology in Your Future?

This video webcast, developed by the Robert Wood Johnson Foundation, explores the various career opportunities available in the field of Epidemiology. The video also offers insights into the Young Epidemiology Scholars (YES) program.

The Age of AIDS, Part I

View at least one of the following Public Broadcasting System (PBS) video segments at some time during the course. This series of videos explores various aspects of the AIDs epidemic, including how epidemiological associations about AIDs were determined.
Part One, Episode One: A Deadly New Disease
Part One, Episode Two: The Spread Escalates
Part One, Episode Four: Scientific Breakthroughs

Optional Resources

Epidemiology for Public Health Practice
“Glossary” (pp. 737–757)It is strongly recommended that you review the Glossary and refer to it throughout the course as needed.

BBC Historic Figures, John Snow (1813–1858)

BBC Historic Figures, James Lind (1716–1794)

Interactive Map: AIDS in the U.S.

This interactive map identifies the HIV statistics for each state in the United States. It provides an example of the type of statistics compiled by epidemiologists. Roll over a state for more details and click on a tab to learn more. 

Order Similar Assignment Now!

  • Our Support Staff are online 24/7
  • Our Writers are available 24/7
  • Most Urgent order is delivered within 4 Hrs
  • 100% Original Assignment Plagiarism report can be sent to you upon request.

GET 15 % DISCOUNT TODAY use the discount code PAPER15 at the order form.

Type of paper Academic level Subject area
Number of pages Paper urgency Cost per page: