EPID: Focus on Surveillance
Kennedy F. Shortridge, Ph.D., D.Sc. (Hon.), C.Biol.
Emeritus Professor, University of Hong Kong, Dept. of Microbiology
The global population is expanding rapidly, bringing with it uncertainties of food availability that will be confounded by climate change. These food issues will also trigger political and global tensions. Food animals are now being raised in vast numbers, engendering increased threats of emerging infectious diseases and possibly a catastrophic influenza pandemic at any time. The H5N1 influenza events of 1997 in Hong Kong and of 2003 in eastern Asia, SARS in southern China in 2003, and pandemic (p)2009 H1N1 viruses show the current value and potential future value of surveillance. Yet, there is insufficient appreciation of zoonotic diseases, difficulty of communication, and complexity of commercial and cultural pressures. Surveillance, observation, and awareness become the cornerstones of “influenza intelligence.” Now is the time for the United Nations (U.N.) and its agencies to grasp the nettle to provide stronger leadership in dealing with emerging and re-emerging infectious diseases and to promote education about them for the global society it serves. The U.N. must provide the impetus for global understanding and responsibility – not only for control but also for prevention.
In 1968, the United States Surgeon General suggested, “It is time to close the book on infectious diseases [and to] declare the war against pestilence won.” However, history proved otherwise. For the next 40 years the world saw the emergence, re-emergence, or re-distribution of a number of viruses, prions (sub-viral), or bacterial infections, leading to a period of unexpected infectious disease problems for humanity. The re-emergence of infectious diseases is multifaceted. Anthropogenic diseases emerged, such as bovine spongiform encephalopathy (mad cow disease), influenza H5N1/97, and Nipah. New social diseases that were exacerbated by socioeconomic and political conditions – the most prominent of which is HIV/AIDS — were recognized. Tuberculosis and childhood infections increased as a result of insufficient basic investment in public health arising from political events. Climate changes drove new geographic boundaries for West Nile and dengue. The first decade of the 21st century also delivered four infectious disease jolts of H5N1 (2003), H7N7 (2003), SARS (2003), and p2009 H1N1 (2009).
The current Director-General of the WHO considers global food crises, climate change, and pandemic influenza to be the three major threats facing humanity. These threats are both mutually exclusive and mutually inclusive. There is a pressing need to raise more conventional food animals [e.g. chicken (H5N1) and pig (p2009 H1N1)] and unconventional animals [e.g. civet cat (SARS) and Bar-headed Goose (H5N1)] in stressful conditions, and there is now greater human encroachment on the animal environment and probably greater use of bushmeat. These conditions may prove ominous for the future.
Scientific challenges and opportunities
The question arises whether infectious disease outbreaks over the last 40 years have been lessened by better surveillance, better interventions, and/or better actions? On one hand, spread of HIV/AIDS (an infection of misery and a potential long-term human pathogen) was the product of international, national, and local inaction, and an indifference to the emergence and spread of disease from specific parts of the world (Africa), and among certain segments of society. The end product was a global disaster. On the other hand, recognition of H5N1/97, Nipah, and SARS was underpinned by understanding local conditions and awareness — itself derived from a pool of understanding from years of influenza virus surveillance of animals in Hong Kong – and each were dealt with immediately at source by the slaughter of chickens, pigs, and civet cats, respectively. (The Hong Kong influenza model was developed in the late 1970s from continuous virus surveillance. It promoted awareness, particularly among government veterinary and medical officials, to be vigilant of a potential pandemic’s emergence. Education and networking among government, universities, and the public bolstered watchfulness and action.). The genesis of the H5N1/2003 virus was charted over four years. Failure to acknowledge its existence led to the “simultaneous” recognition of the virus in eastern Asia for which migratory birds were initially blamed. This represents a failure in responsibility.
Historically, H1N1 pandemics “traceable” to around the 1830s appear to have originated in southern China, although some suggest that the H1N1 pandemic of 1918 initiated in the U.S. The origin of the recent p2009 H1N1 pandemic in Mexico and the U.S. is a departure from the southern China epicenter hypothesis, and is probably the result of the industrialization of pig production. In spite of warning signs from unexpected viral genetic reassortment events taking place in pigs in the U.S., serious surveillance may not have been carried out because: (1) the U.S. is outside the southern China epicenter; (2) it seemed unlikely that, in a world “saturated” with antibodies to H1 and H3 viruses, the genesis of another H1N1 virus could occur; (3) attention was fixated for some time on H5N1 as the next possible pandemic virus; H1, H2, and H3 are the only viruses involved in pandemics since the 1830s, suggesting that there may be a limited range of H subtypes capable of causing human pandemics; (4) of commercial pressures, and (5) of insufficient interaction between industry and government authorities.
Would systematic, proactive surveillance of pigs in the U.S. and Mexico have detected the p2009 H1N1 virus in sufficient time to warn of a possible pandemic? Genetic analysis indicates that initial transmission to humans probably occurred in late December 2008/early January 2009, approximately three months before it was detected in March/early April 2009 (Smith et al, 2009). However, the reassortment events that led to the genesis of the p2009 H1N1 virus in pigs may have taken place three to four years earlier (Smith, personal communication). Accordingly, the answer to the previous question is probably “yes,” proactive surveillance would have detected p2009 H1N1 with time for sounding the alarm. However, without a strong link between investigators, industry, and government (as in Hong Kong), we are doomed to be describing diseases post-hoc rather than predictively through proactive surveillance.
- The U.N. should be the prime body to lead and to establish a unified global approach to virus surveillance across humans and animals, including wild birds. (A signal of intent could be initiated through the World Health Assembly.)
- The science of influenza is complex and needs to be understood by all levels of policy makers from the laboratory to villagers, industry, government, and the U.N. Education is the key to improving human health outcomes.
- The current generation of government and international policymakers’ understanding of EPIDs must be upgraded. This could be mounted in simple interactive courses, using influenza as a model. Organization of these activities could be mounted through institutes like the ISGP, including support from universities and other agencies.
- We cannot assume surveillance systems can run themselves without staff education. This may be achieved by developing courses for prospective administrative staff or undergraduate courses with a stronger science component as parts of degrees or post-graduate courses (e.g. hospital administration courses); restructuring veterinary/university curricula to include greater infectious diseases components and developing new inter-disciplinary courses; and training for extension officers (Shortridge and Gibbins, 2009).
- We must promote the responsibilities of all nations to deal with the influenza problem. Pig/poultry producers and governments should have better interaction and trust to facilitate proactive surveillance. Smallpox and poliomyelitis eradication efforts have set precedence for the effectiveness of international cooperation (Shortridge, 2010).
- Developing global surveillance strategies, particularly at sites with high animal/human interface, is essential to preventing or blunting pandemics.
- It is imperative for humans to move away from animals as a food source. Scientific progress now offers the possibility to genetically harness the power of microbes for large-scale protein production. Benefits include: (1) reduced dependency on production of massive numbers of stressed food animals and the effect on the environment and (2) reduced threats of influenza and other infectious diseases.
- We must ask ourselves, with all the science and technology now available, why is so much effort given to the control of emerging infectious diseases rather than to prevention? (See: early Chinese medical conviction; Shortridge, 2010). In the case of influenza, a mindset change in needed; we must set a goal of no more pandemics. Science needs a focus, a purpose for its application, and a society sufficiently educated to bring it about. Strong, purposeful global leadership through U.N. agencies is immediately required, especially in the face of global food crises and climate changes.
Smith, G.J.D., et al. (2009). Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic. Nature. 459: 1122–25.
Shortridge K.F. and Gibbins A.M. (2009). Risks to human health and food security from the waterfowl /avian influenza connection. Proceedings IV World Waterfowl Conference, 11-13 November 2009, Thrissur, India. Kerala Agricultural University, pp. 28–32.
Shortridge, K.F. (2010). Southern hemisphere, northern hemisphere: a global influenza world. In: Institute of Medicine. The Domestic and International Impacts of the 2009-H1N1 Influenza A Pandemic: Global Challenges, Global Solutions. Washington, D.C.: National Academies Press.
** A policy position paper prepared for presentation at the conference on Emerging and Persistent Infectious Diseases (EPID): Focus on Surveillance convened by the Institute on Science for Global Policy (ISGP) Oct. 17-20, 2010, at Airlie Conference Center, Warrenton, Va.
The following summary is based on notes recorded by the ISGP staff during the not-for-attribution debate of the policy position paper prepared by Prof. Kennedy Shortridge (see above). Prof. Shortridge initiated the debate with a 5-minute statement of his views and then actively engaged the conference participants, including other authors, throughout the remainder of the 90-minute period. This Debate Summary represents the ISGP’s best effort to accurately capture the comments offered and questions posed by all participants, as well as those responses made by Prof. Shortridge. Given the not-for-attribution format of the debate, the views comprising this summary do not necessarily represent the views of Prof. Shortridge, as evidenced by his policy position paper. Rather, it is, and should be read as, an overview of the areas of agreement and disagreement that emerged from all those participating in the critical debate.
- There are scientific models worldwide where infectious disease surveillance has been judged to be successful. It was generally agreed that the more successful elements of these surveillance programs need to be widely emulated.
- Although the scientific credibility and inherent value of surveillance programs are generally recognized, the resultant information has not generally been used by governmental or societal leaders to shape effective policies addressing infectious diseases in a timely fashion.
- The institutions mandated with the responsibility for world health must do significantly more to improve their role in shaping surveillance programs, interpreting the programs’ results, and utilizing conclusions to influence infectious disease policy.
- The design of future surveillance systems must consider how to monitor, quantify, and predict the influence of diverse factors such as animal waste management, vector control, explosive population growth, and local and global climate change. Biosecurity has also become an increasingly important element in the design of surveillance systems.
- To date, the eradication of most infectious diseases has been beyond our current capabilities. More effective use of disease surveillance as a tool to control those diseases is of critical importance if eradication is to become a reality.
There was substantial discussion concerning whether the current ability of the organizations having mandates for global health, such as the United Nations (U.N.) and the World Health Organization (WHO), are failing to meet current needs for disease surveillance given the scope and complexity of global infectious disease threats. A critical aspect of this discussion centered on issues surrounding the urgent necessity to build surveillance capacity and analysis capabilities in countries where the greatest disease risks occur rather than depending solely on external responses. New models for effective disease surveillance based on increased in-country involvement in combination with regional networks are needed to support the international surveillance efforts coordinated by the U.N. and the WHO. The emergence of regional surveillance networks that cross old (e.g., Cold War) geographic boundaries was highlighted as one example of current local capacity building.
The present influenza surveillance system is the most widespread in the world since virus strains can easily and quickly spread worldwide. Yet, even armed with substantial knowledge of the influenza virus, and despite the high burden of this disease in all countries, the availability of the influenza vaccine has not been greatly expanded worldwide. During the 2009 (H1N1) pandemic, governmental vaccine distribution systems did not move unused influenza vaccine from wealthy countries to those tropical areas that lack vaccine protection. This failure to protect overall human health occurred despite strong statements from both the scientific and policy communities declaring that such redistribution was the preferred course of action.
Recent history has provided a highly visible example of an infectious disease epidemic that now is present worldwide, namely HIV/AIDS. Surveillance provided reports suggesting the existence of the virus and disease for many years prior to their formal recognition. This delay in acknowledging the emergence of a major infectious disease and the gap between scientific understanding and policy decisions underscores the need to mobilize the political will required to deploy resources in support of those activities that protect populations at risk. Combating a disease outbreak begins with disease surveillance. However, surveillance has proven ineffective without the means to mobilize political commitments and convince the public to take those steps that can provide some measure of protection. The impact of surveillance in controlling an infectious disease can only be substantial if a society provides the resources needed to implement specific actions. These specific actions must be justified by the appropriate analysis of the evidence uncovered by surveillance.
The Australian livestock industry has developed a five-tier system for indemnification of losses due to disease and their impact on farming conditions. Similarly, in East Africa, index insurance products have been developed for rural communities to increase incentives for disease reporting and protect livelihoods. These examples demonstrate the private insurance market's ability to provide more sensitive risk assessment than is typically generated by governments. The effectiveness of the private sector reflects its ability to understand the financial risks of exposure to diseases and its proximity to the market impact.
As the middle class expands globally, the demand for increased production of food protein from animal sources is intensifying the conditions in which new and persistent infectious diseases in animals may thrive. Such increased food production opens up new avenues for disease transmission from animals to humans (zoonosis) and increases the likelihood of infectious disease outbreaks that affect both animals and humans. The challenges of animal disease surveillance include biosecurity, management of animal waste, disease control in highly populated areas, and the effects of local and global climate change — all of which are extremely difficult to monitor, predict, and quantify.
Scientific opportunities and challenges
The control of influenza has never been attempted on a global scale. Only one area in the world, Hong Kong, has a concerted, active surveillance system for assessing the circulation of influenza strains in all animals. Without establishing a broad network of surveillance systems comparable to Hong Kong's across the globe, widespread control of influenza will not be feasible. Nonetheless, scientifically credible surveillance methods exist that could be used as models for such a global system.
An active global surveillance system that describes the ecology of influenza is a necessary primary step to management of the disease. A baseline can then be produced that can be used in models to illustrate changes in the hosts, reservoirs, and circulating strains. To be effective, this system must include data on animals (wild and domestic), the local environment, humans (their health and behavior), seasons, weather, and climate.
The burden of infectious diseases is interrelated across pathogens. For example, immunity against influenza can provide protection against pneumonia. The basic global map now available for the disease burden is not sufficiently detailed to meet current needs and is outdated with respect to the demands of policy makers. New surveillance technologies, including crowd-sourcing and other proxy measures derived from the Internet, are needed to provide a more complete and interdependent picture of the disease burden for a given locale. Clinical and laboratory diagnoses remain of paramount importance.
In the case of food production, the increased use of industrial food methods and practices might lessen small-scale, unreported contamination that occurs at local levels. However, expanded adoption of industrial food production practices might also concentrate contaminants and develop new breeding grounds for antimicrobial resistance. Accordingly, a challenge arises in using the science and technology of surveillance to disentangle whether food-related outbreaks are artifacts of changes in food practices, products of opportunity, and/or new methods of counting.
Public health advances historically resulted primarily from the adoption and provision of good hygiene, water, nutrition, and improved living standards. It was widely questioned whether less-wealthy countries can control influenza when they have other, more pressing, basic health needs associated with good hygiene, water, nutrition, and the quality of living conditions.
There was general consensus that eradication of the influenza virus is not possible since there currently is no way to eliminate the disease from either animals or humans. However, global control of the disease has never been seriously considered. The complexity of the disease, combined with the lack of basic understanding of some science (e.g., how the influenza virus jumps the species barrier) and the basis for accurately assessing immunity, has deterred attempts to propose a widespread control program. There was considerable disagreement concerning whether global influenza control is feasible. It was contended that worldwide control would be possible with the proper programs, resources, and surveillance in place, especially with direct, continuous monitoring of animal diseases. By contrast, it was argued that disease control on a global scale may not be realistic because such targeted programs would require 10 to 15 years to initiate – an impractical goal, especially when the incentives and advantages are distributed across such a wide number of countries, populations, and industries.
Within this context, it is clear that a better, more comprehensive understanding of the origin of pandemics and of the animal-human interface would encourage a generational shift toward disease prevention rather than the primarily disease control approach now used. The experience in Hong Kong with H5N1 supports the feasibility of such a preventive approach.
While many reports urge the implementation of more infectious disease surveillance, it is not clear at what point these efforts produce “data overload,” in which the availability of so much surveillance data makes it more difficult to conduct a proper analysis. Innovative thinking is needed to understand both how disease surveillance can be further improved and how the analysis of that data can be organized and conducted in ways that facilitate their use in policy decisions. It was further contended that to obtain the political and public support required to implement increased disease surveillance, public health communities must better define and communicate the return on investment (ROI) that governments and their respective communities can reasonably expect.
Large (re)insurers have developed many new lines of products to address novel risks. For example, in 2007, personal pandemic influenza policies became available in China. Insurance industry assessments rank infectious diseases as among the highest risks to the global economy. It was agreed that it would be useful to look toward insurance analyses to assess the ROI in surveillance response systems for infectious diseases.
The global burden of influenza is significant. Although an influenza pandemic represents one of the largest catastrophic threats to global economic security, serious vaccination attempts are made only in wealthy nations. Practical and societal barriers to widespread vaccination must be better understood and appropriately addressed to widen the vaccination net and increase protection.
The time required for influenza vaccine production cycles has been massively reduced through technological advances. Companies can now develop seed strains in days with minimal staff. During the 2009 pandemic, vaccine manufacturers demonstrated this capacity by developing strains despite financial risks to the private sector. However, it was noted that the speed of vaccine production, as well as the rate at which the influenza virus is transmitted, routinely outpaces the time required for the regulatory processes to approve action. It was suggested that attention be given to identifying what specific regulatory reforms are needed to align safety concerns with rapid production and distribution of influenza vaccines.
The role of education and training in influenza control was discussed. Greater clarity was sought on the role that distance education (i.e., for individuals in less-wealthy nations) can play in expanding the number of trained personnel in local settings. It was perceived that investing resources in the training of healthcare professionals within less-wealthy countries would be a major step forward in improving disease surveillance.
In many areas where new infections are found and/or predicted, agricultural and health officials are often politically at odds. The strength of agriculture ministries and their promotion of certain practices (e.g., the use of hormones and vaccines in poultry) could increase threats to local and global health. Better communication and cooperation is needed between these two groups to bridge their competing interests.
Increased use of industrial food production practices might reduce small-scale, unreported contamination at local levels. However, it was asserted that new ways of monitoring the often rapid changes in the scope of food-related outbreaks are needed. It was suggested that care must be taken to ensure that recorded changes are due to actual events and not because of alterations in methodologies used to monitor and analyze food-related outbreaks (e.g., ways of counting).
Influenza constantly circulates in pigs, chickens, ducks, humans, and wildlife. However, not all strains have the potential to result in human pandemics, nor are they all lethal to the economic livelihoods of millions of farmers. Although veterinarians are most likely to notice the emergence of a new variant in the animal population, they often have few resources available for monitoring. Accordingly, attention must be given to enhancing global veterinary monitoring for potential pandemic influenza strains.
Copyright: Institute on Science for Global Policy