When epidemiologists are working to track a disease, the three elements that they focus on are the  agent , the  host , and the  environment . Following are explanations of each element. The  agent  is what causes the disease. The  agent  is often a virus or bacteria but can also be caused by other  agents . In the scenario, described in the Introduction, the  agent  is the E.coli bacteria.  The  host  refers to those who are contracting the disease. The  host  doesn’t necessarily become sick. Hosts can serve as carriers of the disease who do not show outward signs or symptoms.  Finally, the  environment  refers to the external factors that support or cause the disease to spread. In the E. coli scenario, the lettuce became infected either at the farm or during transport; the lettuce was sold to the distributor and then to Sam’s Sandwich trucks; and people ate the lettuce on these sandwiches. Each of these steps is important to tracking the disease, and epidemiologists work diligently to trace and report each of the steps to prevent further transmission of the disease. The following is an example of an epidemiologic triad. Agent : Salmonella bacteria 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 435-440 in your Friis and Sellers (2021) textbook for further explanation. In this Discussion, you will apply the epidemiologic triad to a disease of your choice to gain a better understanding of both the model and the disease.  To prepare   for this Discussion:  Access and review the Epidemiological Triad Learning Interaction. Select an infectious disease from the list proved in List of Infectious Diseases document for Week 1 Discussion.  Review the Week 1 “Ebola Virus Disease in the Light of Epidemiological Triad” (Kaur, Sachdeva, Jha, & Sulania, 2017) resource. Consider how the epidemiologic triad/triangle can be applied to your selected disease. Consider how variations in each factor shown in the example from the textbook can influence the manifestation of the disease..

1. When epidemiologists are working to track a disease, the three
elements that they focus on are the
agent
, the
host
, and the
environment
. Following are explanations of each element.
The
agent
is what causes the disease. The
agent
is often a virus or bacteria but can also be caused by other
agents
. In the scenario, described in the Introduction, the
agent
is the E.coli bacteria.
The
host
refers to those who are contracting the disease. The
host
doesn’t necessarily become sick. Hosts can serve as carriers of
the disease who do not show outward signs or symptoms.
Finally, the
environment
refers to the external factors that support or cause the disease
to spread. In the E. coli scenario, the lettuce became infected
either at the farm or during transport; the lettuce was sold to the
distributor and then to Sam’s Sandwich trucks; and people ate

2. the lettuce on these sandwiches.
Each of these steps is important to tracking the disease, and
epidemiologists work diligently to trace and report each of the
steps to prevent further transmission of the disease.
The following is an example of an epidemiologic triad.
Agent
: Salmonella bacteria
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.

3. 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 435-440 in your Friis and Sellers (2021)
textbook for further explanation.
In this Discussion, you will apply the epidemiologic triad to a
disease of your choice to gain a better understanding of both the
model and the disease.
To prepare
for this Discussion:
Access and review the Epidemiological Triad Learning
Interaction.
Select an infectious disease from the list proved in List of
Infectious Diseases document for Week 1 Discussion.
Review the Week 1 “Ebola Virus Disease in the Light of
Epidemiological Triad” (Kaur, Sachdeva, Jha, & Sulania,
2017) resource. Consider how the epidemiologic triad/triangle
can be applied to your selected disease.
Consider how variations in each factor shown in the
example from the textbook can influence the manifestation
of the disease. Refer to pages 435-440, in your textbook, for
further explanation.

4. By Day 4
Post
a comprehensive explanation of the following:
Identify ebola virus disease Following are explanations of each
element.
Provide an example of an agent that is associated with
the infectious disease that you selected.
Discuss
at least three
examples of environmental factors that contribute to the
likelihood of transmission of the agent to an individual for the
disease you have selected.
Discuss
at least three
examples of host factors that contribute to the likelihood of
transmission of the agent to an individual for the disease you
have selected.