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.

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

To prepare for this Discussion:

• Select one agent of an infectious disease. Select an agent of interest or an agent listed on the CDC’s website at http://wwwn.cdc.gov/nndss/script/conditionlist.aspx?type=0&yr=2013
• Consider how the health condition applies to the epidemiologic triad (also known as the epidemiologic triangle).

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.