Epidemiology is different from medical fields because it does not focus on one individual it focuses on a group. Epidemiology directly impacts public health. Epidemiology is centered on three factors in a population setting, the Host, the Agent, and the Environment. These three factors are part of the Epidemiology Triangle. The Host is the population the disease or health problem concern. The host is the Human who can come in contact with the disease. There are a lot of things that intrinsic the host and are often called risk factors. Opportunities for exposure often are influenced by the person’s behaviors for example Sexual practices, hygiene, a person’s choices and age and sex. Sometimes people are more susceptible due to genetic composition, nutrition, immune system, anatomic structure, present illness, medications and psychological makeup. The Agent is the health concern or the health problem. An Agent must be present for a disease to occur, but presence of an agent is not always sufficient to cause a disease. There are many factors that influnance weather an exposure will to an organism will result in disease, including pathogenicity and dose. The environment is the geographical area where the disease takes place and refers to the extrinsic factors that affect the agent and opportunity for exposure. The factors that are environmentally include social economic factors such as overcrowding populations, sanitation issues and availability of health care. Throughout the remains of this paper there will be examples of…