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Overview of Zoonoses, Emerging Infections, and Public Health

Overview of Zoonoses, Emerging Infections, and Public Health. David D. Blaney, MD, MPH CDC South Asia Regional One-Health Forum April 6-7, 2010. Outline. Interaction between humans and animals and diseases affecting both human and animal health Disease surveillance in humans and animals

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Overview of Zoonoses, Emerging Infections, and Public Health

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  1. Overview of Zoonoses, Emerging Infections, and Public Health David D. Blaney, MD, MPH CDC South Asia Regional One-Health Forum April 6-7, 2010

  2. Outline • Interaction between humans and animals and diseases affecting both human and animal health • Disease surveillance in humans and animals • Role of Public Health Practitioner • Role of Veterinary Practitioner • Integration of human and animal health activities • Examples of integrating human and animal health • International integrated human and animal health organizations and surveillance South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  3. Zoonotic Diseases Definition: A zoonosis is any infectious disease (virus, bacterium, protozoan, prion, fungus, worm) that is able to be transmitted from other animals, both wild and domestic, to humans; or from humans to animals (reverse zoonosis or anthropozoonotic). South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  4. Zoonotic Diseases Of more than 1,400 organisms reported to cause disease in humans, 61% are known to be zoonotic Definition: A zoonosis is any infectious disease (virus, bacterium, protozoan, prion, fungus, worm) that is able to be transmitted from other animals, both wild and domestic, to humans -- or from humans to animals (reverse zoonosis or anthropozoonotic). South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  5. Zoonotic Diseases Of more than 1,400 organisms reported to cause disease in humans, 61% are known to be zoonotic > 70% of newly recognized human infectious diseases (i.e. “emerging diseases”) are of animal origin Definition: A zoonosis is any infectious disease (virus, bacterium, protozoan, prion, fungus, worm) that is able to be transmitted from other animals, both wild and domestic, to humans -- or from humans to animals (reverse zoonosis or anthropozoonotic). South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  6. Zoonotic Diseases Of more than 1,400 organisms reported to cause disease in humans, 61% are known to be zoonotic; > 70% of newly recognized human infectious diseases (i.e. “emerging diseases”) are of animal origin; 80% of infectious agents identified as high risk bioterrorist weapons are zoonotic Definition: A zoonosis is any infectious disease (virus, bacterium, protozoan, prion, fungus, worm) that is able to be transmitted from other animals, both wild and domestic, to humans -- or from humans to animals (reverse zoonosis or anthropozoonotic). South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  7. Impacts of Zoonotic Diseases • Many diseases can impact both animal and human health • Cause human and/or animal illness • Cause human and/or animal death • Economic and social impact • Local, regional, national, and international impact South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  8. Human-Animal Interface South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  9. Categories of Animal to Human TransmissionDirect Transmission Rabies, Brucellosis, Avian Influenza (H5N1) South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  10. Categories of Animal to Human TransmissionIndirect Transmission Brucellosis, Leptospirosis South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  11. Categories of Animal to Human TransmissionVectorborne Transmission Japanese Encephalitis, Dengue, Typhus, Plague, Chikungunya South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  12. Categories of Animal to Human TransmissionAnimal to Human to Human SARS, Bovine Tuberculosis, Seasonal Influenza South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  13. Categories of Animal to Human TransmissionHuman to Animal Tuberculosis, Giardia, novel H1N1 South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  14. Human and Animal Health Effects • Public health concern • Food safety • Impact agricultural productivity • Pose a significant threat to trade South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  15. Emerging Infectious Disease Interface Environment Domestic Animals and Wildlife EID Human EID South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  16. Examples of EID Linked Between Animal and Human Health South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  17. Examples of recent disease (re-)emergence vCJD E. coli O157:H7 Chikungunya West Nile virus Monkeypox SARS Hantavirus pulmonary syndrome Nipah Ebola • Widespread or pandemic: • MDR tuberculosis • XDR tuberculosis • Influenza A (H5N1) and (H7N7) • MDR malaria • Dengue • Pandemic H1N1 Hendravirus Marburg Rift Valley fever

  18. Relative Risk of EID: Zoonotic Pathogen from Wildlife South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh Jones et al, Nature 21 Feb 2008

  19. Relative Risk of EID: Zoonotic Pathogen from Non-wildlife South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh Jones et al, Nature 21 Feb 2008

  20. Be recognized for expertise in animal diseases and treatment Develop awareness of zoonotic diseases which may affect animal owners or consumers of animal products Suggest changes in production activities to increase bio-security and bio-safety Develop professional relationship with local public health officials Maintain awareness of changes in interaction between domestic animals and wildlife Role of Veterinary Practitioner

  21. Objectives of an Animal Disease Surveillance System • Routine surveillance for disease affecting animal productivity • Surveillance to show absence of disease • Within a defined geographical area • Within a specific population/stock • Relevant to domestic and international movement of animals and products • Rapid detection of new and exotic infectious diseases South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  22. Accurate and timely reporting Where and when disease occurred, clinical signs Standardized laboratory diagnostics Action to control spread of disease Evaluate and address deficiencies in animal disease control programs, veterinary infrastructure and balance public health impact, animal productivity, and socio-economic impacts. Objectives of an Animal Disease Surveillance System

  23. Animals are healthier Greater productivity Less loss to disease, death, abortions Improved bio-security Improved trade and market access People are healthier Less chance of disease getting transferred to humans from meat, dairy, or other food products Animals can serve as early warning system (sentinels) for disease in humans Why is this important? South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  24. Be recognized for expertise in human disease epidemiology and prevention Develop awareness of existing/potential zoonotic diseases which may affect public health Develop professional relationship with local healthcare providers and Veterinary health officials and practitioners Work with Veterinary health officials to implement activities to increase bio-security and bio-safety Maintain awareness of changes in interaction between people, domestic animals, and wildlife Role of Public Health Practitioner

  25. Objectives of a Human Disease Surveillance System Rapid detection of new and exotic (to a zone or country) infectious diseases Measure burden of disease or other health-related event Monitor trends in burden of a disease including detection of outbreaks and epidemics South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  26. Guide planning, implementation, and evaluation of programs to prevent and control disease Assess control or eradication of selected diseases and pathogens Evaluate public health programs and policy Objectives of a Human Disease Surveillance System South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  27. People are healthier Less chance of disease getting transferred to humans from meat, dairy, or other food products Animals are healthier More productivity Less loss to disease, death, abortions Improved trade and market access People can serve as early warning system (sentinels) for disease in animals Why is this important? South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  28. “One Health” Concept • Concept linking animal and human health together • Recognizes risk sharing by both human and animal populations • Not just “us versus them”, (risk posed by to animals humans) • Animal populations, human populations, and the environment are all considered when looking at health risks

  29. Many of the objectives of animal and human surveillance systems are identical Detect new and exotic diseases Assess control or eradication of disease Some objectives differ Absence of diseases that are for important for animal health/trade but may not cause illness in humans Joint Animal Human Surveillance South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  30. Current Situation • Often national and international human and veterinary health organizations monitor only human disease or animal disease, but not both together • Lack of communication between human and veterinary can lead to delayed recognition of infectious disease outbreaks • Public health and veterinary government authorities often only start to cooperate together when emerging zoonotic outbreaks occur: • H5N1 avian influenza initiated public health and veterinary cooperation in many countries

  31. Benefits of Integration of Human and Animal Health Activities • Integration can help identify presence and prevalence of some zoonotic, food-borne, or environmental diseases in a region • Identification of disease in one population (e.g., human) can indicate the possible presence in the other (animals) • Animals as sentinels for humans, and humans as sentinels for animals • Allow for assessment of other diseases South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  32. Benefits of Integration of Human and Animal Health Activities • Cooperation and integration can allow for sharing of infrastructure and resources • Integrating surveillance and other health activities may improve cost-effectiveness • May be more effective than conducting human and animal surveillance activities separately • Simultaneous surveillance can provide data to determine effective and efficient response and control strategies South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  33. Benefits of Integration of Human and Animal Health Activities • Gaps in human or veterinary health activities may be identified • e.g., identifying differences in vaccine coverage • May improve contact and health assessment of hard-to-reach communities, e.g. improving contact with mobile pastoralherding communities who seek veterinary care fortheir herds South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  34. Integration of Human and Animal Health Activities • Interaction between human public health and veterinary health must be two way • Activities can be integrated in many ways • Sharing of surveillance data • Standardization of surveillance terminology • Cooperative / joint surveillance activities • Joint actions or intervention • Resource sharing South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  35. Information Flow in Joint Surveillance Provincial Local Regional/ National Local Vet/Para Vet Worker PVOs Feedback Animal and Human Health Team Local Human Health Worker PMOs

  36. Goal of U.S. Surveillance:Collaboration at State and Federal Level State Health Director State Veterinarian Federal Veterinarian for State CDC State based or center Private practitioners Accredited veterinarians State laboratory Private physicians Local public health State public health Federal regional vets Federal animal health techs National laboratory Center-based specialists Reference Laboratories

  37. Integrated Health Surveillance: Brucellosis in Kyrgyzstan • Kyrgyzstan brucellosis incidence: 50 / 100,000 persons • Knowledge is lacking about specific regional incidence and prevalence in humans or livestock (cattle, sheep) • Collaborative integrated human and animal health serological survey was agreed upon by Kyrgyz veterinary and public health authorities • Collaboration between Kyrgyz national veterinary and public health centers, laboratories, and external partners (Swiss Red Cross) Zinsstag et al, Vet Italiana (2009);45:121-133 South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  38. Integrated Health Surveillance: Brucellosis in Kyrgyzstan • Serological survey conducted during national census of the sheep population • Multi-stage cluster sampling design, sampling all persons in households selected for survey, and administering survey questionnaires • Goats, sheep, and cattle in selected households were also tested serologically • Simultaneous investigation of human and animal brucellosis can provide data to determine most cost-effective national control strategy South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  39. Integrated Health Surveillance: Brucellosis in Kyrgyzstan Zinsstag et al, Vet Italiana (2009);45:121-133

  40. Integrated Health Service Delivery: Immunization Programs in Chad • Higher vaccination coverage observed in cattle than children in nomadic pastoralist herders • Led to cooperation between the expanded program on immunization and veterinary services to conduct joint human and livestock immunization campaigns • Demonstrates importance of including communities in surveillance system • Can inform about local health concerns or report problems with health interventions South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  41. Integrated Health Service Delivery: Immunization Programs in Chad Zinsstag et al, Vet Italiana (2009);45:121-133 South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  42. Animals as Sentinels for Surveillance for Human Health Threats • Animals can warn humans about chemical, infectious, and environmental hazards • Avian Influenza (AI) • Sentinel animal flocks • Testing of sick chickens, waterfowl by investigating publichealth and vet teams South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  43. Animals as Sentinels for Surveillance for Human Health Threats • Animals will show clinical signs when infected with many zoonotic diseases, so passive surveillance in animals is important for early detection and control • Active surveillance should be included in surveillance strategy for infections with asymptomatic cases South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  44. Avian Influenza - Background • Highly Pathogenic H5N1 AI is endemic in poultry in many countries across Asia • Spread by infected migratory birds to domestic poultry • Live poultry markets canbe sites for maintenance,amplification and spreadof AI, including highly pathogenic H5N1 AI from birds to humans South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  45. Avian Influenza - Background • Zoonotic transmission from birds to humans continues to be detected, even in areas where poultry outbreaks not reported • Active surveillance in poultry population and markets and passive surveillance in human population (testing and reporting of suspect cases) help track presence and spread of disease South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  46. H5N1 AI Epidemiology • 1997 – First human outbreak in Hong Kong (18 cases, 16 deaths) in visitors to poultry market • 2003-06 – outbreak in Asia, Europe, and Africa • Unprecedented HPAI (H5N1) outbreak in poultry • Farms, backyard flocks affected • Millions of poultry died or killed • 2006: Nigeria, Niger, Cameroon, Egypt, Sudan, Djibouti • Laboratory confirmed cases found in: • Poultry - 35 countries • Wild birds - 28 countries • Human deaths reported in 10 countries by 2006

  47. AI Sentinel Surveillance in Thailand • Main objective is disease eradication • Method – active surveillance survey conducted in poultry-raising households • Collaboration between Animal Health and Human Health agencies • AI can be present in some birds, e.g. ducks, without clinical signs • Active surveillance testing method: cloacal swab used in ducks South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

  48. AI Sentinel Surveillance in Hong Kong • Cloacal swabs or fecal droppings standard method for AI testing at poultry markets • Investigators determined testing of drinking water in cage more sensitive • Method tested as part of ongoing active surveillance in markets • Allows for sampling of all birds in one cage Leung et al, EID (2007); 13(9)

  49. International Integrated Human – Animal Health Organizationsand Surveillance Activities • WHO – World Health Organization • FAO – Food and Agriculture Organization of the United Nations • OIE – World Organization for Animal Health (Office International des épizooties) South Asia Regional One-Health Forum April 6-7 2010 • Dhaka, Bangladesh

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