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sars_study.docxWeek 4: Week 4 - Epidemiology—Introduction
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The study of epidemics is epidemiology. Its primary focus is on the distribution and causes of disease in populations. Epidemiology involves developing and testing ways to prevent and control disease by studying its origin, spread, and vulnerabilities. As a discipline, epidemiologic research addresses a variety of health-related questions of societal importance. Epidemiologic research methods are used by clinical investigators and scientists who conduct observational and experimental research on the prevention and treatment of disease. The Cholera epidemic, a case from the 19th century, was enabled by the global movement of people. Having appeared in India in 1817, it spread throughout Asia and the Middle East within a decade. It was reported in Moscow in 1830 and then spread to Warsaw, Hamburg, Berlin, and London in 1831 (Snow, 1855, 2002). When it crossed the Atlantic to reach North America, Cholera gained the notoriety of the first truly global disease. The modern day world is dominated by free trade and rapid transportation. An unprecedented rate of global interchange of food, consumer products, and organisms—including humans—is occurring. The threat of pandemics in the 21st century has heightened the importance of epidemiology at national and international levels. Although diseases such as Influenza A (H1N1), Severe Acute Respiratory Syndrome (SARS), Acquired Immunodeficiency Syndrome (AIDS), West Nile Virus, Salmonella, are commonly recognized as epidemics, as they cause large scale disruption of health in populations. The field of epidemiology also addresses epidemics of obesity (Ogden et al., 2007), diabetes (Zimmet, 2001), mental health (Insel & Fenton, 2005), and any other disease that may cause large scale disruption of health in populations. In general, there are ten stages to an outbreak investigation: 1. Investigation preparation 2. Outbreak confirmation 3. Case definition 4. Case identification 5. Descriptive epidemiology 6. Hypothesis generation 7. Hypothesis evaluation 8. Environmental studies 9. Control measures 10. Information dissemination Investigation preparation requires a health crisis manager to identify a team of professionals who will lead the outbreak investigation, review the scientific literature, and notify local, state, and national organizations of the potential outbreak. Outbreak confirmation requires actual laboratory confirmation of the disease, which may involve the collection of blood, urine, and stool samples from ill people and performing bacteriologic, virologic, or parasitic testing of those samples. Case definition is the process by which we establish a set of standard criteria to determine who is and is not infected with respect to a specific outbreak; that is, a protocol is developed to determine case patients. Case identification requires the health crisis manager and team of professionals to conduct a systematic and organized search for case patients based on the standard criteria developed in the case definition phase. Here, it is vital that the team identifies both case patients (individuals already infected), as well as individuals who may have been exposed. Descriptive epidemiology requires the team to organize the data—who was infected, when, where, etc.—identify frequencies, and perform basic descriptive statistics that may present patterns. Hypothesis generation requires the team to generate hypotheses as to why the outbreak occurred and compare the situation with previous outbreaks or develop methods to collect additional data. Hypothesis evaluation requires more in depth statistical tests, including an official epidemiologic study (cohort, case control, etc.) and comparing potential risk factors among those infected (cases) and those not infected (controls). Additional studies may call for environmental diagnoses requiring collection and analysis of food, water, and other environmental samples. Once all data has been collected and examined, the team will work to implement control and prevention measures by coordinating with community partner organizations. Finally, the health crisis management team will communicate their findings via an outbreak investigation report that is tailored for the scientific community as well as lay persons. The primary goal of the information dissemination stage is to educate the community about the outbreak and instill the knowledge needed to prevent further outbreaks. Using the navigation on the left, please proceed to the next page. |
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Week 4: Week 4 - The Threat of SARS Case Study
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You are the director of communicable diseases in a city health department, responsible for a large urban community. It is early spring in 2003. For the past two years, your department has been working to control the spread of the West Nile Virus and you are pleased with the progress so far. This morning you read about a suspected outbreak of a new disease called SARS which is suspected to have killed dozens of people in Hong Kong. While West Nile Virus is carried by birds, especially crows, SARS is transmitted among people. When you get to the office and check your email you learn that the World Health Organization has placed a number of East Asian cities off limits for all but essential travel. You also learn that Canada has reported deaths they believe are due to SARS. You are now confronted with addressing a new and virulent contagious disease. What should you do? Using the navigation on the left, please proceed to the next page. |
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Week 4: Week 4 - Health Crisis Management
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A public health crisis is described as an emerging situation that affects a large population, often spanning a wide geographic area, usually in a very short period of time. The severity of the crisis is measured by the number of people affected in relation to the geographic extent or by the intensity of the causative agent, such as a disease, toxin, or poor policy decisions. Health crisis can occur in many forms and at multiple scales. Health care organizations themselves have internal health crises, which are often in the form of spreading infection. This is so common that hospitals employ infectious disease specialists and epidemiologists to routinely locate and contain disease outbreaks. For instance, in the very first chapter of his book, On Washing Hands, Dr. Atul Gawande (2007) describes how inexplicably common it is for hospital personnel to not wash their hands and cause the spread of infections. In the United States, it has been estimated that approximately two million health care associated-infections (HAI) occur each year, resulting in 60,000 to 90,000 deaths. The cost is estimated to be at least $17 to $29 billion (Jarvis, 2007). At a global scale, health crises may be even more difficult to manage owing to several complexities. This is when the infection rates from super-resistant bacteria have increased throughout the world, and humans travel in unprecedented numbers and at a very fast pace. For example, transmitting primarily through the hands of health care workers, the SARS virus—having first appeared in the Guangdong Province of China in late 2002—spread within a few months to over twenty five countries, infecting over 8,000 people and causing 774 deaths, as reported by the Centers for Disease Control and Prevention (CDC). There are several opportunities for such incidents to quickly escalate to crises levels. Public health emergencies may come from several other sectors as well. In its website, the office of the Assistant Secretary for Preparedness and Response (ASPR) of the US Department of Health and Human Services (HHS) lists four major kinds of emergencies: · Oil or chemical spills · Biohazard or infectious disease · Food safety issues · Terrorism or criminal activity It is very likely that all of these emergencies will require health care emergency managers to plan and prepare for contingencies. The outcome of how a crisis is managed is largely dependent on the knowhow, experience, and the personality of the manager. No matter how much planning is done and protocol followed, emergency managers need to have strong leadership qualities in order to handle crises. Having a working knowledge of the health care field is also critical in this context. During an emergent health crisis, the manager needs to coordinate between various groups, communicate decisively and clearly in order to avoid panic, and optimize the distribution of resources. Using the navigation on the left, please proceed to the next page. |
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