Article Review Assignment

PUH 5301, Public Health Concepts 1

Course Learning Outcomes for Unit III Upon completion of this unit, students should be able to:

2. Analyze key public health concepts and principles. 2.1 Describe the different types of epidemiologic studies.

3. Discuss the different public health disciplines’ impact on population health.

3.1 Identify infectious and chronic diseases that contribute to the most incidence, prevalence, morbidity, and mortality within the community.

Course/Unit Learning Outcomes

Learning Activity

2.1

Unit Lesson Chapter 4: Epidemiology: The Basic Science of Public Health Chapter 5: Epidemiologic Principles and Methods Video: Measles Unit III Case Study

3.1

Unit Lesson Chapter 6: Problems and Limits of Epidemiology Video: Measles Unit III Case Study

Reading Assignment Chapter 4: Epidemiology: The Basic Science of Public Health Chapter 5: Epidemiologic Principles and Methods Chapter 6: Problems and Limits of Epidemiology Additional Required Material: In order to access the following resource, click the link below. Astral Studios (Producer). (2010). Measles (Segment 2 of 7) [Video file]. Retrieved from

https://libraryresources.columbiasouthern.edu/login?auth=CAS&url=http://fod.infobase.com/PortalPla ylists.aspx?wID=273866&xtid=51776&loid=188605

To view a transcript of this video, click on the “Transcript” tab near the top right corner of the page.

UNIT III STUDY GUIDE

Defining Epidemiology

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Unit Lesson The Evolution of Epidemiology In 2014, the United States discovered at least 667 measles outbreaks in 27 states, including one of the largest outbreaks with 383 cases in unvaccinated Amish communities in Ohio (Centers for Disease Control and Prevention [CDC], n.d.). The cases discovered in the United States were mainly from people who had travelled to the Philippines, which had also experienced a measles outbreak. Epidemiology is the study of diseases in populations; it seeks to understand the incidence, distribution (when, where, and who), and control of disease in a specific community or population and not necessarily individuals. It studies the determinants of health- related events to control diseases and other health problems. As seen in the situation with measles in the United States, epidemiologists are able to identify the distribution of disease and provide a report that could assist in an intervention within that community. The use of epidemiology can be dated as far back as about 1854 when John Snow, a British Physician, was alarmed by the cholera epidemic that struck London in 1848 (Schneider, 2017). Snow compared the number of deaths in one supplier of water and the number of deaths with another supplier of water. He found that there were fewer deaths with the Lambeth Company than with the Southward and Vauxhall Waterworks Company. He concluded that the deaths were a result of contaminated water; all got their water from the Thames River, but Lambert from a far less polluted area of the river than the sewage polluted area used by the Southward and Vauxhall Waterworks Company (Schneider, 2017). Snow was able to make this conclusion from data collected from the thousands of houses he visited and data collected from the government regarding the number of births and deaths (and causes of deaths). Data or vital statistics have become an epitome of public health all over the world whereby local, state, and federal governments collect information called epidemiologic surveillance. According to the World Health Organization (WHO, 2017), epidemiologic or public health surveillance is defined as the systematic, continuous process of collecting, analyzing, and interpreting health data for planning, implementing, and evaluating public health programs and interventions. One thing to note is that, in epidemiologic surveillance, certain infectious diseases are considered notifiable diseases, and they are supposed to be reported immediately to public health officials when diagnosed. Some notifiable diseases include HIV/AIDS, hepatitis, syphilis, gonorrhea, and mumps. While the federal government has identified about 60 notifiable diseases, some states require public health officials to report other non-infectious or chronic diseases immediately. The information collected is stored in state departments and the Centers for Disease Control and Prevention, and they assist public health officials, especially epidemiologists and researchers, in controlling the spread of disease and in exploring ways in which to increase prevention and improve health. Most local communities also keep their public health data; in Texas for example, HIV/AIDS data can be found for various counties within the state. Epidemiologic Concepts One thing that is extremely important in epidemiology is the level or occurrence of disease in a community or human population. The extent of a certain disease that is commonly in existence in a community or permanently exists in a community is called the endemic or baseline level of disease (Schneider, 2017). This

Measles (Srisa, n.d.)

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may not be necessarily the desired level of disease, considering that it would be a perfect world to have a zero level of disease, but it is an observed level for that community. Malaria, for example, is an endemic because it could be eradicated, but it is extremely common and expected in tropical regions of Africa. The extent of a certain disease may rise more frequently than the usual level of disease in a community. An epidemic refers to an often sudden increase in the number of disease cases, usually above what is expected in that area. Recent examples of an epidemic are the 2009 Indian Swine flu outbreak or H1N1 virus. The outbreak could attack many people at the same time and could spread into many communities. A pandemic is when an epidemic travels across large regions. It could spread across countries or continents. One of the most dangerous global pandemics in history is HIV/AIDS that has spread in several continents, which has made it extremely difficult to contain considering that some people do not get tested, do not protect themselves, and are misinformed about the disease. In order for an epidemic to occur, there has to be an infected host source and a method of transmission to occur. When an infectious female Anopheles mosquito bites a person, the parasite travels to the liver where it is later spread into the bloodstream and invades the red blood cells. Within 48 to 72 hours, the infected person develops chills, fever, and joint pains. If the infected mosquito is not killed (especially since they usually bite at night), it is able to spread the infection to other people. Over the last century, chronic diseases have supplanted infectious diseases as the predominant cause of mortality and morbidity worldwide (Rosenthal, 2015). The threat from infectious diseases still exists, but more light has been shed recently, especially on the various kinds of cancer. Chronic diseases, such as lung, liver, and ovarian cancer, type 2 diabetes, obesity, heart disease, and stroke are among the most common, preventable, and costly health problems. They are usually caused by unhealthy lifestyles like lack of regular check-ups, smoking, alcohol abuse, poor nutrition, lack of exercise, and a prolongation of some infectious diseases, including the human papillomavirus (HPV) and complications of HIV/AIDS. Infectious diseases, on the other hand, are conditions caused by viruses, fungi, parasites, or bacteria. Many organisms that live in our bodies are harmless, but under certain conditions, some of these organisms, like the various kinds of herpes, may cause disease. Infectious diseases can be passed from person to person (syphilis), from animal to person (swine flu), or from insects to person (malaria). In all, epidemiologists have to monitor the measures of disease frequency and the incidence and prevalence rates of all diseases. While incidence rates monitor the number of new cases of diseases, prevalence rates monitor both the number of new and existing cases of diseases. Incidence permits the researcher to determine an individual’s probability of being diagnosed with disease over a given period of time, and prevalence measures an individual’s probability of having disease. While epidemiologists study the incidence and prevalence of diseases, they also have to monitor the morbidity and mortality rates in order to develop an intervention or program for the community. Morbidity is another name for illness or disease. Some people simultaneously have co-morbidities. For example, someone who is type 2 diabetic could also be obese and suffer from a heart disease. Mortality, on the other hand, is another name for death: the number of deaths as a result of disease divided by the total community of population. All these concepts are intertwined in the sense that a disease, tuberculosis, for example, may have a high incidence rate in a certain region but a low mortality rate. Outbreaks generally come to the attention of federal, state, or local health departments through public health or epidemiologic surveillance, which brings into play description epidemiology. When an outbreak happens,

Pandemic versus epidemic

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epidemiologists try to figure out what is known about the disease, who is the originator of the disease, how the disease is transmitted, where the disease is found, and the incubation period of the disease. Therefore, a few characteristics come into perspective, as shown in the below graphic. During the Ebola epidemic, researchers had to figure out the characteristics of the population, to not only stop

the spread but to make sure that it does not happen again. Processes like these could take months and even years, especially when it spreads extremely quickly and the people in contact are not aware of the etiology of the disease. Epidemiological Study Designs and Ethical Concerns It is vital for public health officials to understand the different kinds of epidemiology studies. Most of the studies used are observational, but researchers could also use experimental studies. In observational studies, the researchers do not intervene; they simply observe and systematically collect data without changing the individual (or animal). However, in experimental studies, the researchers intervene to change something (most of the time to give the individual or animal a drug) and then observe what happens. The commonly used studies in epidemiological research are cross-sectional studies, case-control studies, cohort studies, and intervention studies. When conducting epidemiology studies, public health officials are extremely mindful of limitations like bias and ethical problems when selecting participants. Intervention studies, for example, are experimental studies that work with two groups; one group is usually given the intervention while the other group is not or is given a placebo. Then both groups are observed to see the outcome. While this is used to test drugs before they can be approved by the Food and Drug Administration (FDA), it can also cause a lot of ethical problems and lawsuits. It is also for this reason that the FDA would recommend a drug to be developed, tested, and approved within at least 10 years. One of the biggest ethical concerns arises when studying human beings and when making sure that the benefits outweigh the risks. In the 1930s in Alabama, these ethical concerns were raised when at least 400 black men were enticed to be part of a syphilis experiment by the Tuskegee Institute. Even after the emergence of penicillin to treat syphilis in the 1940s, the Tuskegee participants were not given the treatment option (Schneider, 2017). As a result, all studies requiring human subjects must get approval from the Institutional Review Board (IRB). The role of IRB is to make sure that benefits of the study outweigh the risks, and the participants are to be informed in detail about the study. Conclusion Epidemiology is interesting as it is usually considered the backbone of public health for many reasons. For example, without the statistics during a needs assessment, an intervention or program could be unsuccessful

Epidemiology characteristics

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in a community. Epidemiology research helps assists public health officials in understanding the number of people with disease, if the numbers are changing, and how the disease could affect the community.

References Centers for Disease Control and Prevention. (n.d.). Measles cases and outbreaks. Retrieved from

https://www.cdc.gov/measles/cases-outbreaks.html Rosenthal, N. A. (2015, August 1). [Review of the book Infections, chronic disease, and the epidemiological

transition: A new perspective by A. Mercer]. Clinical Infectious Diseases, 61(3), 489–490. https://doi.org/10.1093/cid/civ280

Schneider, M.-J. (2017). Introduction to public health (5th ed.). Burlington, MA: Jones & Bartlett Learning. Srisa, W. (n.d.). Measles (ID 70680828) [Graphic]. Retrieved from https://www.dreamstime.com/ World Health Organization. (2017). Public health surveillance. Retrieved from

http://www.who.int/topics/public_health_surveillance/en/