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Infectious Disease Control

Milestones in Public Health: Chapter 4. Infectious Disease Control. Lectures for Graduate Public Health Education . January 2011. Learning Objectives. Describe the 150-year history of world efforts to control infectious disease

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Infectious Disease Control

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  1. Milestones in Public Health: Chapter 4 Infectious Disease Control Lectures for Graduate Public Health Education January 2011

  2. Learning Objectives • Describe the 150-year history of world efforts to control infectious disease • Discuss Darwin’s concept of adaptation as applied to infectious diseases • Describe the roles of federal agencies and advocacy organizations • Review the CDC’s OPLAN for Avian Influenza 2

  3. Learning Objectives • Describe public health interventions to control communicable diseases • List the purposes of surveillance • Discuss examples of domestic surveillance • Discuss surveillance systems for MRSA 3

  4. Lecture Outline • Historical Perspective • The Milestone and its Impact on Public Health • Aspects of Biology, Behavior and Science of Infectious Diseases • Systems, Policies and Programs • Looking Ahead • Wrap-Up • References and Resources 4

  5. Infectious Disease Control Historical Perspective

  6. Historical Perspective: Infectious Disease Control The War is Over! In 1967, the U.S. Surgeon General William Stewart supposedly stated: “It is time to close the book on infectious diseases, and declare the war against pestilence won.” FAQs (2004) 6

  7. Historical Perspective (Cont.) To tell the real war story, the current one, we need to go back to 1859 to Charles Darwin’s Theory of Natural Selection as the explanation of the functional designs of organisms. Neese and Williams (1996) 7

  8. The Concept of Adaptation by Natural Selection • Adaptations by which we combat pathogens • Adaptations of pathogens that counter our adaptations • Maladaptive but necessary costs of our adaptations Neese and Williams (1996) 8

  9. New Take on Darwinian Medicine • Bacteria and viruses seen as sophisticated opponents in an endlessly escalating arms race… • These pests have evolved ways to overcome our defenses or even use them to their own benefit • Explains why we cannot eradicate all infections Neese and Williams (1996) 9

  10. New Take on Darwinian Medicine(Cont.) From time of Darwin to those premature declarations of the end of the war against infectious disease, there is a rich history of our increasing understanding of infectious diseases and of our efforts to control them. Neese and Williams (1996) 10

  11. Stern and Markel (2004) Identified three eras of international approaches to controlling infectious diseases: • 1851-1881 Setting the stage: The first International Sanitary Conference • 1881-1945 Advent of germ theory and rise of bacteriology • 1945-2004 The WHO: A new definition of health to the present 11

  12. Growth in Understanding the Spread of Disease from Person-to-Person • Since microbes are invisible to humans, nothing was known about them until the 1600s • Microorganisms seen under microscopes of Robert Hooke (1664) and Anton Van Leeuwenhoek (1684) had to be definitively linked to disease, which was accomplished by Robert Koch in 1891 Stern and Markel (2004) and Black (2008) 12

  13. Koch’s Postulates of 1891: The Germ Theory of Disease Four fundamental concerns: 1. Microbe must be present in every case of the disease 2. Microbe must be isolated from the diseased host and grown in culture 3. Disease must be reproduced when a pure culture is introduced into a non- diseased susceptible host 4. Microbe must be recoverable from an experimentally infected host Fredricks and Relman (1996) 13

  14. Infectious Disease Control The Milestone and Its Impact on Public Health

  15. Top 10 Causes of Death (Due to Infectious Disease)by Broad Income Group WHO (2007)

  16. Populations at Risk • In the developed world, old people are most at risk of infectious diseases, while in the developing world, infants and young children remain most at risk • Other vulnerable populations to hazards of infection include immunocompromised persons and those on steroid therapy for chronic diseases Milestones (2006) 16

  17. Why Are Infectious Diseases Still Among the Leading Causes of Death Worldwide? • Emergence of new infectious diseases • Re-emergence of old infectious diseases • Persistence of intractable infectious diseases Milestones (2006))

  18. Infectious Disease Control Aspects of Biology, Behavior and Science of Infectious Diseases

  19. Infectious Disease Interventions Three major public health interventions to control communicable diseases follow: • Improved resistance to environmental hazards • Improved environmental safety • Enhanced public health systems Department of Health and Human Services 19

  20. Improved Resistance to Environmental Hazards • Hygiene • Nutrition • Immunity • Antibiotics • Psychological factors • Exercise • Genetic alteration Aschengrau & Seage (2008) 20

  21. Improved Environmental Safety • Sanitation • Air • Water • Food • Infectious agents • Vectors • Animal reservoirs Aschengrau & Seage (2008) 21

  22. Enhanced Public Health Systems • Access • Efficiency • Resources • Priorities • Containment • Contact tracing for prophylaxis and therapy • Education • Social forces • Laws • Measurement of problems and of the efficiency and effectiveness of control Department of Health and Human Services 22

  23. Four Important Systems-related Means of Controlling Communicable Disease • Containment • Contact tracing for prophylaxis and therapy • Education • Measurement (surveillance) 23

  24. Surveillance The ongoing systematic collection, collation, analyses, and interpretation of data and the dissemination of information to those who need to know so that action may be taken Aschengrau & Seage (2008) 24

  25. Purposes of Surveillance • Monitor disease trends • Monitor progress • Estimate magnitude of a problem • Detect outbreaks of an infectious disease • Evaluate interactions and programs • Identify research needs Aschengrau & Seage (2008) 25

  26. Surveillance is Crucial for Prevention and Control Examples of national and international surveillance programs follow: • Summary of notifiable disease (National Notifiable Disease Surveillance System) • S. aureus-related hospitalizations 26

  27. Domestic Surveillance: National Notifiable Disease Surveillance System (NNDSS) • Statistical summary of notifiable diseases in U.S. is published to accompany each volume of Morbidity and Mortality Weekly Report by CDC • Contains texts, graphs, and maps of official occurrences of nationally notifiable diseases in U.S. for the year • Operated by CDC in collaboration with Council of State and Territorial Epidemiologists (CSTE) • Published in week reported CDC (2010) 27

  28. Domestic Surveillance: NNDDS (Cont.) When published, data can be used by: • State and local health departments • Schools of public health • Communications media • Local, state and federal agencies • Other interested agencies CDC (2010) 28

  29. S. Aureus-Related Hospitalizations Example of analysis of U.S.-based S. aureus-related hospitalizations using administrative databases and other surveillance sources raised possibility that majority of the overall increases in S. aureus-related discharges are due to community-associated diseases • Jhung’s Enhanced Detection of Staphylococcus aureus-related Hospitalizations Using Administrative Databases, United States, 1999-2005 Jhung (2008) 29

  30. S. Aureus-Related Hospitalizations (Cont.) Findings: • S. aureus-related discharges increased significantly over the period 1995-2005 • Majority of staph-related discharges due to skin infections in patients less than 45 years of age Jhung (2008) 30

  31. Surveillance Systems for MRSA (Methicillin Resistant Staph Aureus) • NHSN – National Health Care Safety Network - Monitors health care-associated infections including those caused by MRSA • ABCs – Active Bacterial Care - Surveillance of the Emerging Infections Programs • From 2004-present, invasive MRSA infections are monitored in nine sites across the U.S. which currently participate in the ABC’s MRSA surveillance, representing a population of 16.3 million persons • NNIS-National Nosocomial Infection Surveillance System (1970’s-2005) Publications and Reports Milestones (2006) 31

  32. Public Health System Capacity For surveillance system and response networks to be successful in prevention and control, the following are necessary: • Good communication among all government levels: local, state, and federal • Working across disciplines • Policy development • Planning • Training • Improved laboratory capability • Human resource capacity IOM (2003) 32

  33. The Problem with Surveillance Experience has shown that despite the U.S.’s extensive disease surveillance system and response network, there exist gaps in the ability to detect outbreaks early. IOM (2003) 33

  34. Challenge for Public Health The challenge is to use surveillance information systematically in outcome-driven business practices to: • Improve emergency response • Build routine organization effectiveness • Give necessary attention to specific emergent issues and simultaneously to develop fundamental infrastructures IOM (2003)

  35. Application to Surveillance We must: • Improve information • Process information better • Connect information into response plans/systems in order to link surveillance to more efficient action to identify and control ID IOM (2003) 35

  36. Infectious Disease Control Systems, Policies and Programs

  37. Human and Microbial Factors in Emergence of New Infectious Diseases • Human demographics • International travel • Technology • Industry • Climate change • Poverty • War • Intent to harm • Breakdown in public health measures • Microbial adaptation, changes, and counter defenses Milestones (2006)

  38. Antibiotic Resistance Our use/misuse/overuse of antibiotics in human and veterinary medicine and in animal feed has resulted in large amounts of antibiotics in our pantries and environments. Milestones (2006) 38

  39. Federal Agencies and Advocacy Organizations Various organizations have provided regulations and guidance, creating much controversy about correct ways to handle growing problem of antibiotic resistance • Federal agencies: • Centers for Disease Control and Prevention (CDC), US Department of Agriculture (USDA), Environmental Protection Agency (EPA), Food and Drug Administration (FDA) and National Institutes of Health (NIH) • Advocacy organizations: • American Public Health Association (APHA) and American College of Physicians (ACP) Milestones (2006) 39

  40. Federal Agencies • CDCViews antibiotic resistance as one of its top concerns • USDA- Concerned with labeling and claims on meat packages -70% of antibiotic use is an additive to animal feed, not to treat disease Milestones (2006) 40

  41. Federal Agencies (Cont.) • EPAHas jurisdiction and authority over water pollutants that enter environment • NIHConducts research, develops solutions and educates public about emerging problem Milestones (2006) 41

  42. Federal Agencies (Cont.) • FDA • Has authority to restrict use of antibiotics in animals based on the potential risk to human health • Controversy has surrounded use in animals due to strong evidence that practice of giving livestock antibiotics results in inability to treat some human illness Crawford (2003), Milestones (2006), Pyrek (2003), and Taraporewala (2008) 42

  43. Federal Agencies (Cont.) • In 1998, the FDA began to restructure drug-approval system for use of antibiotics in food producing animals • In 2003, the FDA took action in the campaign against resistance in issuing new labeling regulations for human use: the intention was to reduce the inappropriate prescription of antibiotics for common ailments such as ear infections and common coughs Crawford (2003), Milestones (2006), Pyrek (2003), and Taraporewala (2008) 43

  44. Federal Agencies (Cont.) • In 2005, the agency withdrew a livestock antibiotic based on its growing concerns about resistance being transmitted from food animals to humans • FDA has variety of regulatory tools to help developers of antimicrobial drugs, including an accelerated approval process for drugs that: • treat illnesses • show meaningful benefit over existing drugs to control disease Crawford (2003), Milestones (2006), Pyrek (2003), and Taraporewala (2008) 44

  45. Federal Agencies (Cont.) • Guidance document issued targeting pharmaceutical industry which develops veterinary drugs for widespread agricultural use • FDA’s National Center for Toxicological Research has studied mechanisms of resistance to antibiological agents in human GI tract Crawford (2003), Milestones (2006), Pyrek (2003), and Taraporewala (2008) 45

  46. Advocacy Organizations The American Public Health Association (APHA) has prepared a fact sheet on antibiotic resistance, supporting: • Education programs for providers and patients in the appropriate use of antibiotics • Improved surveillance programs at local and national level, with feedback to policy makers, health officials and providers APHA (2003)

  47. Advocacy Organizations(Cont.) • Withdrawal of all antibiotics given to healthy animals for economic reasons when those antibiotics are also used for people APHA (2003) 47

  48. Advocacy Organizations(Cont.) The American College of Physicians (ACP) has issued guidelines for patients, multiple levels of health care providers and others in support of: • Adequate funding for state surveillance efforts to study antibiotic resistance and other diseases • In-state surveillance programs for diseases that are nationally notifiable, and subsequent reporting of such information to the CDC Milestones (2006) 48

  49. Infectious Disease Control Looking Ahead

  50. Looking Ahead Major infectious disease threats currently facing the U.S. and world: • Every important bacterium has become resistant in some way to antibiotics • The spread of avian influenza (H5N1) viruses among birds continues to cause human disease with high mortality and to pose threat of a pandemic • One-stop access to U.S. government avian and pandemic flu information at http://www.pandemicflu.gov/ Milestones (2006) 50

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