EPID: Focus on Surveillance
Surveillance for Livestock Diseases That Impact
Food Security and Food Safety**
Radford Davis, D.V.M, M.P.H, D.A.C.V.P.M.
Associate Professor, College of Veterinary Medicine, Iowa State University
Livestock play an important role around the world as a source of food, income, fuel, and fertilizer, and contribute significantly to the food security and nutrition of people in both urban and rural areas. Approximately one billion people in poverty derive their livelihoods from livestock, a sector that in developing countries accounts for more than one-third of the agricultural gross domestic product (GDP). Those in poorer developing countries are more likely to own livestock, live in closer association with their animals, yet also have little in the way of animal disease prevention or control, veterinary care, or disease surveillance. It is from these same developing countries that many new diseases emerge on the global stage.
Having efficient national surveillance and monitoring systems for animal diseases and zoonoses in domestic and wild animals is now widely considered essential to understanding and combating diseases that threaten animal/human health and food security, and is a recommendation of this paper. Such systems should be able to rapidly detect diseases early in their emergence and generate reliable information on disease situations within the countries. Surveillance systems are not a “one size fits all” solution for every country, but should be tailored. More emphasis should be placed on establishing such surveillance and reporting systems in poor countries, where the need is greatest and where diseases are most likely to emerge. Additionally, closer collaboration between animal health, human health, and environmental sectors at the country level are needed to accurately identify and address emerging and persistent disease threats. Challenges in developing a surveillance system range from design and funding issues to community concerns and political backing.
Livestock diseases disrupt trade, negatively impact local and regional economies, exacerbate poverty, and reduce production and productivity. From livestock come a number of diseases that threaten food safety, food security, and human health. Zoonoses from livestock can cause significant morbidity among humans, leading to chronic disability, long-term loss of income, and medical expenses. The mechanisms to collect, analyze, and disseminate information regarding animal health or food safety problems are often minimal in areas where livestock are most abundant, as are systems for detecting outbreaks and emerging pathogens.
It is believed that 30 percent of people in industrialized countries suffer from foodborne illnesses of animal origin every year, but the cost of foodborne illnesses in many developing countries is not fully known since such cases are often not reported, and systems to track such illnesses are uncommon. In the United States, foodborne illness outbreaks linked to animals are estimated to cost more than $8 billion (U.S.)/year. Globally every year, many zoonotic diseases continue to have a tremendous impact on health, food safety, livelihood, and trade (e.g., anthrax, brucellosis, tuberculosis). Poor infectious disease surveillance and control efforts have led to the global spread of diseases of major zoonotic importance, and from responses to these we have learned that disease surveillance systems must incorporate animals, humans, and ecosystems.
Population-dense animal operations, the clustering of these facilities near urban populations, and the movement of animals, people, and pathogens between intensive and traditional production systems all coalesce to amplify risks to animal/human health and food security. Climate change will also contribute to this mix, altering the landscape of disease and insect vector distribution, wildlife habitat, and the timing, frequency, and severity of outbreaks. Surveillance programs will be challenged by all of these. Animal disease surveillance systems exist at the international level and, to some degree, at the regional level. Some countries have national systems, but this is less common in developing countries, where diseases are most likely to emerge. One international system is the Global Early Warning System (GLEWS). GLEWS pools up-to-date information collected by the Food and Agriculture Organization (FAO), the World Organization for Animal Health (OIE), and the World Health Organization (WHO), to better detect emerging diseases (zoonotic and nonzoonotic) earlier and thus contain and control epidemics. These systems only function where information at the local level is available. One major lesson learned in the fight against avian influenza “is the central importance of efficient surveillance, effective intersectoral collaboration, a well-designed national strategy and sustained political will (Anonymous, 2008).”
Economic and animal life losses from the spread of transboundary diseases can be monumental: the 2001 United Kingdom foot and mouth disease (FMD) outbreak led to 6 million dead animals, agricultural economic losses of£3.1 billion (U.K.), and a heavy decline in tourism; bovine spongiform encephalopathy (BSE) caused a $20 billion (U.S.) economic impact; and avian flu had more than $10 billion (U.S.) in impact. Yet, rinderpest — the second disease in history to ever be eradicated — once ravaged Europe, Asia, Africa, and the Middle East. Its toll on livestock, wildlife, and humans ultimately garnered political will, leading to its eventual eradication. Such an accomplishment would not have been possible without active surveillance programs in place.
Scientific opportunities and challenges
It has been considered “inappropriate to formulate a ‘one size fits all’ response to disease because people and countries are affected differently depending on their economic circumstances (Anonymous, 2009)” Similarly, there is no one solution to animal disease surveillance. This will vary by country, region, culture, level of endemic disease, funding, and trade level. Surveillance systems, among other things, must be cost-effective, flexible to fit any disease or condition, rapidly implementable, and give a good picture of animal health within the country. But they should also be able to detect and identify unusual events and sound an alarm. The effectiveness of surveillance depends upon support and aid at the local level, cooperation and communication between agencies, and unwavering political support. For this support, the objectives of each animal disease surveillance system must be defined and understood by those involved at all levels. Challenges to building a country-level surveillance system in developing countries are many and certain questions have to be answered:
- What is the laboratory capability to detect a pathogen?
- Where should sampling take place (e.g. slaughter plant, points of sale)?
- How is the information collected and shared, and who is entrusted with it?
- Are there people trained in the appropriate fields (e.g. microbiology, epidemiology)?
- Is there cooperation among country agencies/ministries?
- How are animals identified and products tracked?
- What will be the outcome of the system, and how will outcomes be distributed and used?
- What technology will work in a country, and who will train the workers in it?
- How will the system be paid for?
Developing a system means engaging citizens and educating them on how this system will translate to saving money, protecting animal/human health, and opening trade. Challenges exist in reaching out to the community, incorporating wildlife in disease recognition and reporting efforts, and in understanding the farmer’s position. The importance of disease detection and reporting by veterinarians, farmers, animal workers, and community members must be a message that the government stands behind. Risks and incentives vary with the farmer and the type of production method used (e.g. intensive production versus traditional production), and poor countries face different incentives than wealthier ones. Challenges also exist in bridging the gap between sectors and ministries. Risk assessment of animal and food systems is needed. Analysis of animal systems, markets, transportation systems, buying/selling, slaughtering, cultural sentiments/beliefs, and occupational attitudes pose challenges to a successful surveillance system and require scientists, social scientists, political scientists, and country leaders to work together.
Incursion of disease in a country can mean the loss of export markets valued in billions of dollars per year. This, in turn, impacts livelihoods, food security, lowers GDP, and can initiate economic/ political instability. Countries have different priorities and varying funds to dedicate to surveillance. Policies advocating international support help not just a given country, but other countries as well.
- In creating and maintaining animal disease surveillance programs, policies must be developed that encourage intersectoral collaboration and the protection of animal/human health simultaneously. Such policies should consider the small livestock holder or gender issues that may occur. Policies also must outline: who maintains the system, who sends alert notices, and how control measure decisions will be carried out; who should keep surveillance data, and who should have access to it; how concerns of commodity groups and farmers about litigation or unwanted attention can be addressed; and how policy can balance confidentiality with the protection of health, food security, and trade.
- Cross-border and regional surveillance are complementary to national surveillance, so agreements with neighboring countries must be encouraged.
- Funding for surveillance should tie in with national animal identification and tracking programs, national laboratory capacity, and indemnity payments to farmers (if necessary).
- Policy makers need to understand the many ways in which livestock support livelihoods and improve food security, and the wide reach livestock have on their general economies.
- Policies should encourage transparency in disease reporting and not punish animal producers by forcing them to shoulder the cost of disease containment.
Anonymous. (2008). Contributing to One World, One Health: A Strategic Framework for Reducing Risks of Infectious Diseases at the Animal–Human–Ecosystems Interface.
** 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 Dr. Radford Davis (see above). Dr. Davis 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 Dr. Davis. Given the not-for-attribution format of the debate, the views comprising this summary do not necessarily represent the views of Dr. Davis, 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.
- The significant impact of animal diseases on human health, as related to social, economic, and political realities, is a critical issue that must be considered in designing almost any infectious disease surveillance systems.
- Systems for livestock surveillance require design considerations and investments tailored to the needs of specific communities in both less-wealthy and wealthier countries. Synergies and advances could be achieved through integrating livestock, wildlife, and human health surveillance infrastructures.
- Contamination and methods of disease containment and prevention are continuing challenges in the cross-border movement of livestock and food. The use of vaccination in protecting “at risk” livestock from certain diseases that would subsequently permit the animals’ inclusion in the human food chain is not yet widely accepted.
- Incentives are needed for timely and accurate disease reporting. Currently, the consequences of identifying livestock diseases are often perceived to be punitive by food producers as well as by local and regional governments. These consequences often have deleterious effects on economies.
- The current variability of standards for surveillance of animal diseases diminishes both their individual and collective value. Setting appropriate standards locally and regionally will be a significant step to improving the effectiveness of animal surveillance.
- The surveillance capability directed toward animal diseases needs to be increased in a manner that makes it sustainable, especially in developing economies where it may not be seen as a policy priority. This goal can be achieved by improving local livestock husbandry and veterinary skills and by delivering support in a culturally sensitive manner.
The role of animal disease in the overall structure of human disease surveillance involves a complex, overlapping set of priorities. First, livestock diseases have a significant impact on local and regional economies. Disease outbreaks among animals can worsen human poverty and reduce overall productivity both locally and regionally. Second, with a growing world population there is an ever-increasing need for animal-derived protein as a food source. Third, infectious diseases that spread throughout animal and human populations separately can independently cross country borders. Fourth, zoonotic diseases that cross from animals to humans pose significant threats to human health worldwide while simultaneously threatening the protein supply as a food source.
Concern was expressed that if animal protein sources become scarce from infectious disease or from measures required to counter such diseases (e.g., livestock culls, bans on importing/exporting), already fragile political and economic regimes may further destabilize. Livestock surveillance for animal diseases is, therefore, of relevance to national and international security even if these diseases do not spread to humans.
There are many changing patterns of human behavior that relate to the intersection of food and infectious diseases. For example, changes in animal husbandry and farming methods as well as increasing urbanization all influence the risks of infectious diseases, especially in domesticated animals. Additionally, less-wealthy countries often have greater dependence upon their livestock both as a source of economic well-being and as a food source. These same individuals routinely live close to the animals. These factors make it exceptionally complicated, both technically and from a societal perspective, to effectively conduct disease surveillance in livestock.
Recurring climate conditions, climate change, and local weather fluctuations are major factors affecting the appearance of infectious diseases in livestock. A variety of mechanisms must be considered for vector distribution and wildlife habitat changes.
Livestock disease surveillance is inadequately funded either because meager resources in general are available for its support, even in wealthy countries, or there is a low priority for disease monitoring in animals within governmental organizations. The World Bank, for example, has only one person dedicated to livestock issues in Africa. Similarly, the United States Agency for International Development (USAID) has few people devoted to issues associated with livestock diseases, although historically many diseases affecting humans have originated with the animal populations living near humans. An observation was made that funding is often directed at individual, specific diseases, but it is frequently unclear why such choices are made. There often is no apparent rationale or strategy identified.
Funding available for livestock disease surveillance does not meet the significance or scale of the related human health implications and issues were raised regarding how and when funding becomes available for animal surveillance. Funding is often allocated only after a significant event affecting human health has been identified (frequently via a disease outbreak in the human population). The comment “human health will always trump animal health” was made. However, no such funding difficulties were experienced during the Hong Kong avian influenza outbreak, wherein animal disease monitoring was given priority.
Livestock issues are regularly left to private industry to address, and routinely are associated with that industry’s own agenda (e.g., protecting a specific product). Less-wealthy countries are often poorly supported in the arena of disease surveillance in livestock. In addition, animal health professionals often feel undervalued and held in low esteem by their human health counterparts, a phenomenon observed in both less and more wealthy countries.
Wildlife and plants are often omitted from the surveillance equation. Professionals from each specialty routinely work in isolation from one another and there is little crossover between their professional training. Moreover, relevant public health education is sometimes neglected in the training associated with livestock and animal health.
The “One Health” paradigm was a frequent topic of the debate. The value of integrating services for human and animal health (including wildlife) surveillance was underscored as a critical effort to be undertaken if disease surveillance in humans is to be improved. Even though the meaning of “One Health” remained open to interpretation, the concept of integrated disease surveillance to encompass animals and humans was strongly endorsed. Internationally, the United Nation’s (U.N.’s) Food and Agriculture Organization (FAO) is increasingly concerned that diseases present in animal wildlife will contaminate domestic animals, thereby creating further challenges for protecting the food chain.
Cross-border contamination and the spread of infectious diseases such as West Nile and foot-and-mouth disease (FMD) into the United States are indicators of why coordination between disease surveillance in animals and humans is important. Both positive and negative consequences emerged. The work at Plum Island is a good example of how training opportunities, focused on certain foreign diseases, can be offered. The West Nile experience in the U.S. illustrates that surveillance can be undermined by the incompatibility of data systems used by various agencies (e.g., USDA and CDC). Similar problems were noted for international organizations. The fact that agencies could not communicate hampered effective collaboration and response.
Concern was expressed that regulations need to be tougher regarding the importation of livestock and livestock products. The Australian system, where strict entry requirements are enforced, may provide good guidance.
There was much discussion concerning the potential negative ramifications on the individuals, livestock communities, and even countries reporting an outbreak of an infectious disease in animals. For example, livelihoods may be ruined for farmers whose animals are infected (e.g., via the slaughter of their animal commodities). Moreover, the wider economy can be greatly harmed not only by the animal disease itself, but also by an ineffective reporting process. This was witnessed during the 2001 United Kingdom FMD outbreak (in this instance, both the agricultural and tourist industries were devastated). The political and economic consequences of infectious disease reporting may undermine the effectiveness of disease surveillance in livestock. Rather than “shooting the messenger,” there was wide support for developing systems that incentivize timely and accurate reporting for all stakeholders (e.g., food producers).
Paradoxically, the geographic and demographic areas with the weakest capacity for infectious disease surveillance in animals are those where animal-specific infectious diseases are most likely to emerge. How such capability for surveillance can be developed globally was vigorously debated, but it was difficult to identify any simple model that did not involve providing substantial resources to offset the financial impact of controlling a disease outbreak. Any comprehensive surveillance system that promotes accurate reporting must begin with a consideration of local conditions and sensitivities of the agricultural communities directly affected.
Currently, surveillance and monitoring standards vary greatly across different regions, countries, and communities. As a result, the types of information collected are so irregular and diverse that useful comparisons are rarely found. Even in wealthy countries, accurate information regarding the cost of foodborne illnesses is not routinely accessible. However, using U.S. data, it is estimated that the cost of foodborne illnesses is $152 billion (U.S.) per year. It has also been estimated that approximately 30 percent of people in wealthy countries suffer from foodborne illnesses of animal origin every year. Although it is believed that the reporting of foodborne diseases is underestimated in less-wealthy countries, foodborne diseases are still considered to present serious problems in these countries where the infectious disease surveillance infrastructure is often rudimentary.
Scientific opportunities and challenges
Surveillance of emerging infectious diseases is most useful when pathogens are identified at their source. Awareness of this reality supported the development of the “One Health” approach, wherein surveillance is conducted holistically across animal and human spheres. Barriers to this approach include challenges in collecting appropriate metrics, sharing data across disciplines, and developing the tools necessary to make linkages between animal and human health clearer.
Vaccines that are becoming available for animal-based infectious diseases (e.g., for FMD) could potentially curtail outbreaks in both animals and humans. However, vaccinated livestock are not currently accepted into the human food chain as a matter of policy. Acceptance of animal vaccination and the associated technology may depend on the ability of the scientific community to distinguish vaccinated cattle from infected cattle, a research area that needs immediate attention.
The practices used in the collection of surveillance data identifying the presence of the disease, as well as characterizing its properties, have improved for some specific diseases, but in general require improvement. Significant advances in disease data collection could be made if the successful methodologies currently directed at a specific disease, species, or population were creatively applied to other diseases and population groups. In addition, disease surveillance may be more effective and efficient if approached holistically whenever possible. For example, dual testing (i.e., in which multiple conditions are tested simultaneously) could be applied more widely. Organizing disease surveillance systems that cross disciplines is essential, but the major challenges remain primarily issues of policy within organizations and between countries. Rigorous laboratory discipline will be critical in building the necessary trust for this type of cross-discipline, cross-border approach.
Since animal diseases often reduce livestock populations, it would be useful to obtain an accurate understanding of how reductions in the availability of protein in the food supply impact human health. It also would be useful to obtain similar types of information concerning the influence on human health from decreases in poultry and egg production caused by influenza outbreaks. These types of causal relationships, if significant, are relevant to the policy community’s agenda when assessing the value of disease surveillance in animals.
There is fragmentation in almost all surveillance systems well beyond the separation of disease surveillance for animals and humans. For example, comprehensive disease surveillance systems need to integrate data on animal and human health, climatic conditions, population and societal variations, and ecological influences.
It was uniformly agreed that widespread adoption of a “One Health” paradigm is needed for infectious diseases, particularly those that relate to food. It was clear that major steps are needed to learn how to integrate a “One Health” approach into existing disease surveillance models, into the creation of joint animal/health training initiatives, and into greatly diverse types of disease surveillance infrastructure now found globally. In addition, it was suggested that disease surveillance should not only integrate animal and human health but also take into consideration climatic, ecological, and societal factors. Given the potential impact of animal-based infectious diseases on human health, international economic prosperity, and border security, it was concluded that substantially larger investments in livestock surveillance are needed.
There were several specific issues endorsed as steps in the right direction. Future surveillance systems must recognize and incentivize the critical need for timely and accurate reporting from farming and food-producing communities. A multinational perspective is needed to create a high quality “One Health” approach. Creating internationally accepted standards for disease surveillance would ensure uniformity and, thereby, comparability of the surveillance information collected. In this latter case, it was suggested that standardization be viewed as a two-step process, in which the principles and objectives of animal surveillance are agreed upon, and performance standards then established. Modest efforts are already under way in this arena, particularly within the World Organisation for Animal Health (OIE), which provides standard guidelines as a tool for assessing the veterinary infrastructure of countries.
It was noted that policy makers must be cognizant of the potential judicial implications of the information coming from disease surveillance systems, especially with respect to governments themselves. An example was given of a particular case where a farm was identified as the source of a specific food contamination. The farmer contested this claim in court and sued the government. Because testing results did not provide unequivocal proof of the contamination source, the government lost the case. Consequently, the government was more hesitant in its response to subsequent disease outbreaks. It was contended that incidents of this kind undermine the future value of disease surveillance and that safeguards must be put into place to protect both parties’ interests.
It was generally agreed that training of a new generation of professionals, including animal disease specialists, is a key component in the development of sustainable disease surveillance systems. Even though it is widely recognized that increasing the number of individuals who are well trained in both animal and human health practices is important, care must be taken not to train people without giving proper consideration to the availability of sustainable jobs. The success of the Cuban model of sending veterinarians to villages to develop local expertise was noted as an example to emulate. The issue of gender diversity in disease surveillance education was also raised. Since women are the primary animal caretakers in many areas of the world, it is appropriate that women receive better education in general and access to training programs (e.g., via outreach initiatives) to facilitate both better animal health practices and animal disease surveillance.
The importance of understanding social, behavioral, and cultural factors related to animal diseases and human health was raised on numerous occasions. For example, it was contended that if risks concerning bushmeat consumption are to be addressed and if people are to change their behaviors regarding hunting, better understanding is needed with respect to the cultural and social factors driving the perceived value of bushmeat as a food source (e.g., hunger and preference). It was argued that research through the social sciences would help clarify these issues.
Since countries lacking effective disease surveillance infrastructure may not welcome input from other countries, regardless of its positive intent, considering different models of delivering external support that transcend local cultures would be prudent. The notion of sending “SWAT”-style teams into affected areas was dismissed as inappropriate because it would not provide sustainable services. Attention was drawn to the methods used by the U.S. Department of Defense (DoD) overseas laboratories in successfully responding to zoonotic and animal disease outbreaks. These laboratories offer broad-based capabilities to host countries, but avoid imposing on the host countries’ priorities by waiting until those countries solicit help. This form of coordination would provide useful training opportunities to areas where surveillance is currently subpar.
Copyright: Institute on Science for Global Policy