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Emerging and Reemerging Infections.


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    1. EMERGING INFECTIONS DISCOVERY, DETECTION NETWORKING Dr.T.V.Rao MD Dr.T.V.Rao MD

    2. Infectious disease is one of the few genuine adventures left in the world. The dragons are all dead and the lance grows rusty in the chimney corner . . . About the only sporting proposition that remains unimpaired by the relentless domestication of a once free-living human species is the war against those ferocious little fellow creatures, which lurk in the dark corners and stalk us in the bodies of rats, mice and all kinds of domestic animals; which fly and crawl with the insects, and waylay us in our food and drink and even in our love. - (Hans Zinsser,1934 quoted in Murphy 1994) Dr.T.V.Rao MD

    3. What is a Emerging Infectious Disease • The discovery of disease-causing pathogens is an important activity in the field of medical science, as many viruses, bacteriaprotozoa, fungi, helminthesand prions are identified as a confirmed or potential pathogen. A Center for Disease Control program begun in 1995 identified over a hundred patients, with life threatening illnesses which were considered to be of an infectious cause, but could not be linked to a known pathogen. The association of pathogens with disease can be a complex and controversial process, in some cases requiring decades or even centuries to achieve total control on the etiological agents. Dr.T.V.Rao MD

    4. EMERGING INFECTIOUS DISEASES Microbes and vectors swim in the evolutionary stream, and they swim faster than we do. Bacteria reproduce every 30 minutes. For them, a millennium is compressed into a fortnight. They are fleet afoot, and the pace of our research must keep up with them, or they will overtake us. Microbes were here on earth 2 billion years before humans arrived, learning every trick for survival, and it is likely that they will be here 2 billion years after we department. (Krause 1998). Dr.T.V.Rao MD

    5. Direct economic impact of selected infectious disease outbreaks, 1990-2003 Heymann DL. Emerging and re-emerging infections. In Oxford Textbook of Public Health, 5th ed, 2009, p1267. Dr.T.V.Rao MD

    6. WHOWarns the Trends • The World Health Organization warned in its 2007 report that infectious diseases are emerging at a rate that has not been seen before. Since the 1970s, about 40 infectious diseases have been discovered, including SARS, Ebola, Avian flu, and Swine flu. With people traveling much more frequently and far greater distances than in the past, the potential for emerging infectious diseases to spread rapidly and cause global epidemics is a major concern. Dr.T.V.Rao MD

    7. Many are Zoonotic Infections. • Many emerging diseases arise when infectious agents in animals are passed to humans as zoonosis. As the human population expands in number and into new geographical regions, the possibility that humans will come into close contact with animal species that are potential hosts of an infectious agent increases. Dr.T.V.Rao MD

    8. Emerging Zoonosis • Emerging zoonotic diseases have potentially serious human health and economic impacts and their current upwards trends are likely to continue. Examples are avian influenza, Bovine Spongiform Encephalitis (BSE) and the Nipah virus. Some of the "lingering" zoonosis are re-emerging in some regions, although they seem to attract less public awareness. Brucellosis, dog rabies and parasitic diseases such as cysticercosis/taeniasis and echinococcosis/hydatidosis for example. Dr.T.V.Rao MD

    9. Climate change Promotes Emerging Infections • Climate change is increasingly becoming a concern as a factor in the emergence of infectious diseases. As Earth's climate warms and habitats are altered, diseases can spread into new geographic areas. Dr.T.V.Rao MD

    10. How HIV Emerged • The example of an emerging infectious disease that can be attributed to human practices is HIV. It is thought that humans were first infected with HIV through close contact with chimpanzees, perhaps through bush meat hunting, in isolated regions of Africa. It is likely that HIV then spread from rural regions into cities and then internationally through air travel Dr.T.V.Rao MD

    11. Emerging infections can be caused by: • Previously undetected or unknown infectious agents Known agents that have spread to new geographic locations or new populations Previously known agents whose role in specific diseases has previously gone unrecognized. Re-emergence of agents whose incidence of disease had significantly declined in the past, but whose incidence of disease has reappeared. This class of diseases is known as re-emerging infectious disease Dr.T.V.Rao MD

    12. Emerging Diseases are New to our knowledge • Emerging infectious diseases are caused by new or previously unrecognized microorganisms (. Although the term became part of the journalist’s lexicon in the 1990s, emerging infectious diseases have long been recognized as an important outcome of host-pathogen evolution. Because emerging infections may have severe public health consequences, they are a focus of both the popular press and scientific research. Dr.T.V.Rao MD

    13. Infectious diseases are not Static but New are Emerging • The changing landscape of infectious diseases over the past 2 decades has astounded the medical PROFESSIONALS and the PUBLIC. Emerging pathogens that cause new diseases (e.g., severe acute respiratory syndrome–associated coronavirus [SARS-CoV]), newly recognized microbial agents of known diseases (e.g., human metapneumovirus), and rapidly evolving pathogens (e.g., influenza viruses) all contribute to this seismic shift Dr.T.V.Rao MD

    14. Respiratory Infections are Major Threat • Acute respiratory infections are, globally, the major cause of mortality in children 5 years of age. The advent of diagnostic platforms suited to surveillance as well to clinical application will reduce the morbidity and mortality of respiratory Dr.T.V.Rao MD

    15. Dr.T.V.Rao MD

    16. Factors Contributing to Emerging Infections • Several factors contribute to the emergence of new infectious diseases. They include the increasing growth and mobility of the world’s population, overcrowding in cities with poor sanitation, massive food preparation and international distribution, Dr.T.V.Rao MD

    17. Dr.T.V.Rao MD

    18. Changes in human behavior, food habits and environment • Unsanitary food preparation, exposure of humans to disease vectors and reservoirs, and ecological changes that alter the composition and size of insect vectors and animal reservoirs. Dr.T.V.Rao MD

    19. Animal origins of Emerging Infections • Some emerging infections are caused by microbes that originate in nonhuman vertebrates. Hantavirus pulmonary syndrome was first noted in the Four Corners area of New Mexico in 1993. The disease is caused by Sin Nombre virus, which is endemic in the deer mouse (Peromyscus maniculatus).An increase in the deer mouse population might have been a factor. In 1992–93, abundant rainfall produced a large crop of piñon nuts, which are food for both humans and the deer mouse. As the mouse population rose, contact with humans increased. Dr.T.V.Rao MD

    20. Animal origins of Emerging Infections – Hanta Virus • The virus is excreted in mouse droppings, and contaminated blankets or dust from floors provided opportunities for human infection. Because humans are not the natural host for Sin Nombre virus, the human disease is rare. Dr.T.V.Rao MD

    21. Emergence of Lyme disease, • The emergence of Lyme disease, t he infection has probably been present in North America for millennia, but it was only in the 20th century that conditions in the northeastern US changed to favor the propagation of Lyme disease. Dr.T.V.Rao MD

    22. Re-emerging Infectious Diseases Dr.T.V.Rao MD

    23. Age old infections can be Reemerging • Some emerging infectious diseases are caused not by new pathogens, but by the re-emergence of microbes that had been successfully controlled. The mosquito-borne dengue virus was shown in 1903 to be the causative agent of dengue fever, a disease accompanied by fever, rash, and arthralgia. Fifty years later, a new disease caused by the virus, dengue hemorrhagic fever, was identified in Southeast Asia Dr.T.V.Rao MD

    24. Pan American Health Organization • The Pan American Health Organization led efforts to eradicate the mosquito vector of dengue virus, Aedes aegypti, from most of Central and South America. As a consequence, dengue fever and dengue hemorrhagic fever were largely eliminated from all but Southeast Asia. Unfortunately, the mosquito-eradication programs ended in the 1970s, leading to reinfestation of the Americas. Dr.T.V.Rao MD

    25. Dengue – A Reemerging Infection • Dengue virus has been reintroduced into the Caribbean, the Pacific, Australia, and the Indian subcontinent and has appeared for the first time in China, Venezuela, and Brazil. Intercontinental transport of car tires containing mosquito eggs has been implicated in the spread of the virus. Dr.T.V.Rao MD

    26. Millions are affected with Dengue • Currently there are an estimated 100 million cases of dengue fever and several hundred thousand cases of dengue hemorrhagic fever each year, and 2.5 billion people are at risk for infection. Dr.T.V.Rao MD

    27. Unfulfilled Gaps to Molecular Methods • In recent years, there has been substantial progress in applying molecular biologic advances to respiratory virus diagnosis nonetheless, a major gap has been the lack of a cost-effective,systematic way to identify the causes of respiratory diseases in populations. Dr.T.V.Rao MD

    28. Drug Resistant Pathogens are Emerging • The problematic as the threat of emerging infectious diseases is the emergence of drug-resistant pathogens, which can turn a conquered microbe into a new threat. Low-cost, common antibiotics can no longer clear infections of Escherichia coli, Neisseria gonorrhea, Pneumococcus, Shigella, and Staphylococcus aureus. Dr.T.V.Rao MD

    29. Dynamics of Modern Life Contributed • The cost and length of treatment of many common diseases are increased, or infections may be refractory to treatment. The changing dynamics of a growing population children’s day care centers, and the overuse of antibiotics, both in humans and in the food chain, have contributed to the emergence of drug-resistant microbes. Dr.T.V.Rao MD

    30. Drug Resistant Malaria a grave threat to Developing Countries • The emergence of resistance of Plasmodium falciparum to chloroquine, once a mainstay in the prevention of malaria, has led to a global resurgence of this disease Dr.T.V.Rao MD

    31. Increasing Human Comfort and Changing Life styles too Contribute • Humans are always providing new ways to meet new pathogens. Air travel, dam construction, hot tubs, air conditioning, blood transfusion, deforestation, day care centers, and urbanization are some of the technological and social changes that influence the spread of microbes. Dr.T.V.Rao MD

    32. Need for Antibiotic Stewardship • While rising rates of antimicrobial resistance are driving many institutions to adopt antimicrobial stewardship programs, many are finding the principle difficult to put into practice. Some physicians from across the medical spectrum ignore recommendations to reduce unnecessary use of antimicrobials. Dr.T.V.Rao MD

    33. Dr.T.V.Rao MD

    34. Ever Increasing Population in Developing Countries • Most importantly, growth of the human population continues, providing interactions with other humans and the environment on an unprecedented scale, and ensuring the propagation of new diseases. Dr.T.V.Rao MD

    35. One Health • One Health is the collaborative effort of multiple disciplines – working locally, nationally, and globally – to attain optimal health for people, animals, and our environment. Dr.T.V.Rao MD

    36. One Health Initiative (OHI) has four long-term goals • Goal 1: Develop, implement and sustain a national strategy for improved public health based on the principles of One HealthGoal 2: Create national awareness within the veterinary and medical professions; the broad scientific community; government institutions; the political leadership; and the general public of the power of One Health to improve the health of people, animals and the environmentGoal 3: Illustrate the value of implementing One Health principles through specific Demonstration ProjectsGoal 4: Extend the One Health Initiative to the international community to achieve tangible improvements in global health Dr.T.V.Rao MD

    37. Unfulfilled Gaps to Molecular Methods • In recent years, there has been substantial progress in applying molecular biologic advances to respiratory virus diagnosis nonetheless, a major gap has been the lack of a cost-effective,systematic way to identify the causes of respiratory diseases in populations. Dr.T.V.Rao MD

    38. We can Track very Fast • Emerging infections can be tracked by the hour on the Internet (ProMED-mail, (www.promedmail.org)and in scientific journals (e.g., Emerging Infectious Diseases). Dr.T.V.Rao MD

    39. Emerging Infections Network • In 1995, the CDC granted a Cooperative Agreement Program award to the Infectious Diseases Society of America (IDSA) to develop a provider-based emerging infections sentinel network: the Emerging Infections Network (IDSA EIN). Dr.T.V.Rao MD

    40. How Emerging Infectious Diseases Network works • The Emerging Infections Network (EIN) is a provider-based sentinel network designed to help the public-health community detect trends in emerging infectious diseases. Dr.T.V.Rao MD

    41. Emerging Infections Network Works • IDSA EIN has evolved into a flexible sentinel network composed of over 1,100 infectious disease specialists primarily from North America, with some global members. The overarching goal of the EIN is to assist CDC and other public health authorities with surveillance for emerging infectious diseases and related phenomena. Dr.T.V.Rao MD

    42. The Specific goals of the EIN are to: • Detect new or unusual clinical events; • Identify cases during outbreak investigations; • Gather information about clinical aspects of emerging infectious diseases; • Help connect members to the CDC and other public health investigators; and • Develop new methods for gathering epidemiological and clinical information. Dr.T.V.Rao MD

    43. STRATEGIES TO REDUCE THREATS • IMPROVE GLOBAL RESPONSE CAPACITY • WHO • National Disease Control Units (e.g. USCDC, CCDC) • IMPROVE GLOBAL SURVEILLANCE • Improve diagnostic capacity (training, regulations) • Improve communication systems (web, e-mail etc.) • Rapid data analysis • Develop innovative surveillance and analysis strategies • Utilize geographical information systems • Utilize global positioning systems • Utilize the Global Atlas of Infectious Diseases (WHO) Dr.T.V.Rao MD

    44. STRATEGIES TO REDUCE THREATS • USE OF VACCINES • Increase coverage and acceptability (e.g., oral) • New strategies for delivery (e.g., nasal spray administration) • Develop new vaccines • Decrease cost • Decrease dependency on “cold chain” • NEW DRUG DEVELOPMENT Dr.T.V.Rao MD

    45. STRATEGIES TO REDUCE THREATS • DECREASE INAPPROPRIATE DRUG USE • Improve education of clinicians and public • Decrease antimicrobial use in agriculture and food production • IMPROVE VECTOR AND ZOONOTIC CONTROL • Develop new safe insecticides • Develop more non-chemical strategies e.g. organic strategies • BETTER AND MORE WIDESPREAD HEALTH EDUCATION (e.g., west Nile virus; bed nets, mosquito repellent) Dr.T.V.Rao MD

    46. ROLE OF THE PUBLIC HEALTH PROFESSIONAL • Establish surveillance for: • Unusual diseases • Drug resistant agents • Assure laboratory capacity to investigate new agents (e.g., high-throughput labs) • Develop plans for handling outbreaks of unknown agents • Inform physicians about responsible antimicrobial use Dr.T.V.Rao MD

    47. ROLE OF THE PUBLIC HEALTH PROFESSIONAL • Educate public about • Responsible drug compliance • Emergence of new agents • Infection sources • Vector control • Malaria prophylaxis • Be aware of potential adverse effects of intervention strategies • Anticipate future health problems • Promote health and maximize human functional ability Dr.T.V.Rao MD

    48. Our Vision should look for Our Survival • Human population growth, technological advances, and changing social behaviors lead to the selection of new microbial pathogens. Antimicrobial drugs, vaccines, diagnostics, and treatments for emerging infectious diseases must be developed. The selective forces that drive the emergence of new infectious diseases, and the implications for our survival, are just beginning to be understood. Dr.T.V.Rao MD

    49. Role of Microbiology Crucial link • The importance of Microbiology laboratories rests with prompt identification and reporting can cure with simple remedies, as most of the emerging infections respond to several drugs and choice lies with optimal selection based on Antibiograms, as resistance is not a menace with emerging, newer and uncommon isolates Dr.T.V.Rao MD

    50. Up gradation of Diagnostic Microbiology Laboratories a Must • The modern generation of Microbiologists should be familiar with Identification of the Microbes with newer generation of Technological advances. Dr.T.V.Rao MD