The word epidemiology was derived from the Greek words where “epi” means upon, “demos” means people, and “logos” means study. Epidemiology can be defined in detail as the study of distribution and determinants of health-related states or events in specified populations, and the application of this study to the prevention and control of health problems. (Last, 2001) Here, in the definition the distribution refers to analysis of persons, classes of people, places that are being affected by the specific disease and determinants refers to factors that influence population health; these factors may be chemical, physical, biological, social, economic, cultural, behavioral or genetic. Health-related states refers to causes of death, diseases and behaviors such as use of tobacco, use of health services and reactions to preventive treatments. Specified population refers to those groups who indicate identifiable characteristics and application to prevention and control is aim of public health to protect, promote and restore health. Epidemiological study focuses on a certain population that can be defined in terms of geographical or other criteria. The population may be selected from specific country or area at a specific time. Once population is selected, it can be further divided into subgroups based on age, gender, ethnicity or so on. Epidemiologists usually study on issues related to disability, illness, and death; they are more concerned about improving health and positive health states. Public Health refers to combined actions in course of improving population health. One of the tools used for this purpose is epidemiology. In past, epidemiology studies focused more on cause of communicable diseases and that leads to work in identification of preventive methods. (Bonita, Beaglehole, & Kjellstorm, 2006) Steps and Methods of Epidemiology
Epidemiology employs different sound scientific methods for the inquiry of the problem. It is a data-driven process following an unbiased and systematic approach for the collection, interpretation and analysis of data. As for basic methods, epidemiology studies make careful observations and compare them via valid comparison groups. The observations like number of persons suffering from a particular disease in a particular area and time or the frequency of exposure with disease among people are different from that what is expected. There are other scientific methods also been used in epidemiology including informatics and biostatistics with economic, behavioral, social and biologic sciences. (U.S. Department of Health and Human Services) Epidemiology is also often called as the science of public health. It is a quantitative discipline that is based on current knowledge of statistics, probability and sound research methods. Moreover, it is also method of causal reasoning that develops and tests hypothesis defined in scientific fields like physics, behavioral sciences, biology and ergonomics. An epidemiological study is comprised of the following steps: * Initial observation and data collection of the population to assess the high frequency of a particular disease or outbreak during a specific time period. * Develop a case by defining the percentage of population at risk because of the certain disease. * Collect and analyze data and describe disease under study by means of epidemic curve, spot map and tabulation to show the frequency rate of risk factors. * Develop hypothesis
* Conduct analytical studies by measuring risks and refining hypothesis. * Test hypothesis and summarize findings
* Suggest and define interventions or preventive programs. (Health Knowledge, 2012)
Routine and Research Data Related to AIDS in USA
Acquired Immunodeficiency Syndrome or AIDS was first identified in USA in 1981 as unique disease entity. As according to statistics there were about 10 million people who suffered from human immunodeficiency...