1
Introduction

Epidemics of infectious diseases have been among the most frightening and disruptive of natural disasters since at least the Middle Ages, when recurring outbreaks of the plague killed millions of people. Researchers in the 19th century discovered that the plague was transmitted to humans by fleas from infected rats. Scientific research has since illuminated the causes of many epidemic diseases and has provided tools to control and in some cases eliminate them; by the middle of the 20th century, many researchers regarded the diseases as a significantly diminished threat. However, in the globally interconnected world of the 21st century, it is clear that the threat of epidemics and pandemics1 remains a current, and even urgent risk. Publicity associated with the potential for the avian influenza virus to mutate in such a way that it is both easily transmitted from person to person while maintaining extreme virulence has highlighted the broader problem: Conditions around the globe are ripe for the development of epidemics of zoonotic diseases—any disease or infection that is naturally transmissible from vertebrate animals to humans2—that have the potential to become pandemic. Unlike other public health threats such as tubercu-

1

The difference between an epidemic and a pandemic, while not precise, is one of scope, with a pandemic affecting a much larger number of people over a much wider geographic range than an epidemic. An epidemic is defined as “the occurrence in a community or region of an illness [or other health-related event] clearly in excess of normal expectancy.” A pandemic has been defined by the Centers for Disease Control and Prevention as “a global disease outbreak” (PandemicFlu.gov, 2008).

2

“Zoonoses may be bacterial, viral, or parasitic, or may involve unconventional agents” (WHO, 2008c).



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1 Introduction E pidemics of infectious diseases have been among the most frighten- ing and disruptive of natural disasters since at least the Middle Ages, when recurring outbreaks of the plague killed millions of people. Researchers in the 19th century discovered that the plague was transmitted to humans by fleas from infected rats. Scientific research has since illumi- nated the causes of many epidemic diseases and has provided tools to con- trol and in some cases eliminate them; by the middle of the 20th century, many researchers regarded the diseases as a significantly diminished threat. However, in the globally interconnected world of the 21st century, it is clear that the threat of epidemics and pandemics1 remains a current, and even urgent risk. Publicity associated with the potential for the avian influenza virus to mutate in such a way that it is both easily transmitted from person to person while maintaining extreme virulence has highlighted the broader problem: Conditions around the globe are ripe for the development of epidemics of zoonotic diseases—any disease or infection that is naturally transmissible from vertebrate animals to humans2—that have the potential to become pandemic. Unlike other public health threats such as tubercu- 1 The difference between an epidemic and a pandemic, while not precise, is one of scope, with a pandemic affecting a much larger number of people over a much wider geographic range than an epidemic. An epidemic is defined as “the occurrence in a community or region of an illness [or other health-related event] clearly in excess of normal expectancy.” A pandemic has been defined by the Centers for Disease Control and Prevention as “a global disease outbreak” (PandemicFlu.gov, 2008). 2 “Zoonoses may be bacterial, viral, or parasitic, or may involve unconventional agents” (WHO, 2008c). 

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 GLOBAL SURVEILLANCE OF ZOONOTIC DISEASES losis and malaria, the emergence of these zoonotic diseases represents the potential of rare events with catastrophic consequences, as seen in the HIV epidemic and the 1918 influenza pandemic. Although news stories tracking the path of cases of H5N1 avian influ- enza or highly pathogenic avian influenza (HPAI), or describing an out- break of Ebola in Africa, have captured public attention, they have not always made clear the nature of the threat, the risk of infection, or the tools and structures available to human and animal health authorities to protect the public from infections with these diseases. Human diseases of animal origin—including AIDS, Severe Acute Respiratory Syndrome, HPAI, and Bovine Spongiform Encephalopathy (BSE, causing new variant Creutzfeldt-Jakob disease)—present threats to human health and animal trade. These and several other zoonotic diseases have emerged recently, as patterns of human–animal contact have been changing in noteworthy ways. Intensifying means of food production, more rapid travel and transport of people and animals across borders and continents, changing patterns of land use, and a host of other factors have contributed to conditions that favor the transmission of pathogens that develop from animal populations and then make the jump into human populations. To date, researchers and public health advocates have focused on surveillance3 as the critical tool for detecting and monitoring outbreaks of zoonotic diseases in human and animal populations, but questions remain as to how to make zoonotic disease surveillance more comprehensive and timely in human and animal populations in order to prevent or minimize the potential for outbreaks to occur in human populations. CHARGE TO THE COMMITTEE With the support of the U.S. Agency for International Development, the Institute of Medicine and the National Research Council convened the Committee on Achieving Sustainable Global Capacity for Surveillance and Response to Emerging Diseases of Zoonotic Origin to investigate conditions in which these diseases emerge in human and animal populations, and ways to protect the public from them. The charge to the committee is found in Box 1-1. Members of the committee, whose biographies are included as Appendix A, include experts with a wide array of experience in multiple 3 The World Health Organization defines surveillance as “the systematic ongoing collection, collation, and analysis of data for public health purposes, and the timely dissemination of public health information for assessment and public health response as necessary,” and it may be conducted by institutions of various kinds (WHO, 2008a). These principles would also pertain to animal health surveillance.

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 INTRODUCTION BOX 1-1 Statement of Task The Institute of Medicine and the National Research Council will convene an expert committee to provide consensus advice on the challenge of achieving sustainable global capacity for surveillance and response to emerging diseases of zoonotic origin such as avian influenza. The committee will address the following issues: 1. Review the emergence and spread over the last several decades of a diverse range of agents of zoonotic origin; 2. Summarize what is known about the causes underlying this growing phenom- enon, trends in these factors, and the implications for long-term domestic and international development and security; 3. Assess the evolving nature, extent, and risks of animal and human interactions, focusing specifically on recent infectious disease events of international signifi- cance, such as H5N1 influenza; 4. Review the historic human and animal health responses to emergent zoonotic diseases along with lessons learned that may be applicable to future threats; 5. Review the current state of global systems for surveillance of zoonotic infec- tions in human and animal populations; 6. Develop conclusions on the balance between emergency response to threats and establishing sustainable global surveillance capacity for early detection, mitigation, and characterization of known and unknown threats; 7. Identify and prioritize for the international context recommendations to strengthen and improve coordination of the human and animal health sys- tems in order to achieve a sustainable and integrated institutional capacity for timely surveillance that could improve prevention of and response to zoonotic diseases across both realms; and 8. Explore options—including policy and regulatory options, such as international agreements—to mitigate and decrease the threat of emerging zoonotic dis- eases worldwide, and to improve coordination between governments and other relevant international organizations. disciplines ranging from emerging infectious disease surveillance to veteri- nary medicine in developing countries to bioinformatics. ORGANIZATION OF THE WORKSHOP SUMMARY The committee held a 2-day workshop in June 2008 to begin its explo- ration of those issues, as summarized in this document. The workshop agenda and a list of participants are included in Appendixes B and C, respectively. The workshop provided an overview of the patterns observed in studies of zoonotic diseases and of the likely future trends in the emer-

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 GLOBAL SURVEILLANCE OF ZOONOTIC DISEASES gence of these diseases, described in Chapter 2, and then addressed several currently active surveillance systems for detecting potential zoonotic dis- eases in animal populations, which are described in Chapter 3. Chapter 4 discusses early warning systems for identifying emerging zoonotic diseases in humans, and Chapter 5 describes current laboratory and epidemiological capacity in several countries and laboratories. Chapter 6 summarizes the wide-ranging discussion of these issues at the end of the workshop. The purpose of the workshop was to gather information to help the committee address issues in the Statement of Task (Box 1-1). The informa- tion provided in the workshop summary is directly derived from short pre- sentations and remarks made by workshop participants. The document has been shaped to produce a readable narrative and does not necessarily follow the order of the presentations at the workshop. With the exception of brief background statements, this summary is limited to what was discussed at the meeting and the PowerPoint presentations used by the speakers, whose biographies are included in Appendix D. The materials in this document do not necessarily represent the view of the committee, the Institute of Medicine, or the National Research Council. The committee will, however, draw on the information provided in this workshop summary to develop a consensus report with recommendations that will address the enumerated items in the Statement of Task. The committee plans to issue its consensus report and recommendations in summer 2009.