Epidemiology in Public Health Nursing When a disease is described as endemic, it usually refers to the expected or normal prevalence of an infectious agent for a specific group or region (Beaglehole, Bonita, and Kjellstrom, 1993). The cause of malaria, the parasite Plasmodium faciparum, is limited to tropical and subtropical regions of the world, including Central and South America, Central and South East Asia, and Sub-Saharan Africa (Hay et al., 2009). Malaria is therefore endemic to these regions.

The definition of pandemic varies depending on which international or national health agency or organization is referred to (Doshi, 2011), but generally speaking, a pandemic represents at least two epidemics of a single novel infectious agent, occurring at the same time in at least two distinct populations or geographic regions. While many health organizations include widespread morbidity and mortality in the definition of pandemic, the recent global 2009 H1N1 influenza outbreak was declared a pandemic by the World Health Organization despite no evidence that the H1N1 virus was capable of causing unusually high levels of illness and death. The H1N1 virus had been discovered decades earlier and therefore wasn't a novel strain of influenza.

Epidemiology represents a scientific approach to the study of specific health issues in a defined population and the use of such findings to improve health-related policy. For example, the number of children that are now considered obese has tripled over the past 40 years, leading epidemiologists and health policy makers...

Policies proposed or implemented to control obesity include the elimination of trans-fats in foods, school exercise programs, and high taxes on high caloric beverages.
The number of adults who are obese are described in terms of incidence or prevalence, with the former representing the number of new cases that are diagnosed within a defined period of time and the latter representing the number of individuals having the disease or condition at any point in time (Crighton, 2000). For example, the incidence of obese adults has doubled since 1960 and the prevalence has risen from 15.0% to 32.9% between 1980 and 2004 (Hurt, Kulisek, Buchanan, and McClave, 2010, pp. 780-781).

The terms morbidity rate and mortality rate refer to the prevalence of disease symptoms and deaths, respectively. For example, anorexia nervosa patients frequently experience severe symptoms and therefore their morbidity rate is high (Hillege, Beale, McMaster, 2006, p. 1017). With a mortality rate near 20% the seriousness of the symptoms is evident.

Relative Risk or risk ratio is a measure of the risk that a defined population of individuals exposed to a toxin or infectious agent will develop symptoms or die (Beaglehole, Bonita, and Kjellstrom, 1993, p. 28). Relative risk can also be used to indicate reduced risk of disease or conditions through lifestyle or dietary modifications. For example, White men with a body mass index above 40 kg/m2 have a relative risk for mortality of…