2
Critical Need to Protect US Animal Agriculture

IMPORTANCE OF ANIMAL AGRICULTURE

Value of and Demand for Animal Agriculture

Agriculture and food make up a major part of the US economy. In 2011, US farm cash receipts amounted to $366 billion, of which about $165 billion accrued was attributed directly to the livestock¹ sector (USDA-ERS, 2012a). Livestock and livestock-product exports amounted to $26 billion in 2011, about 20% of total agricultural exports. In 2011, production agriculture accounted for about 1% of the US gross domestic product, total employment in agricultural and related industries was about $2.3 million, and the net trade balance from the agricultural sector was about $37 billion (USDA-ERS, 2012a). The crop sector depends heavily on feedstock demand from the domestic livestock production sector. The food sector is much larger: about 8.3 million people are employed in occupations related to food preparation and service (BLS, 2012a,b), and in 2010, US consumers spent about 9.4% of their disposable personal income on food (USDA-ERS, 2011). In 2012, US producers and ranchers are forecasted to produce 91.6 billion pounds of meat (beef, pork, lamb, chicken, and turkey); hens are projected to produce 6.62 billion dozen table eggs and 1.05 billion dozen hatching eggs; a US dairy cow is expected to produce an average of 21,825 pounds of milk; and US dairy cattle collectively are forecasted to produce 201.1 billion pounds of milk (USDA-ERS, 2012b).

The world population is expected to increase to 9.3 billion by 2050 (United Nations, 2011). With projected increases in global population and wealth and the resulting demographic changes that could lead to a burgeoning middle-class in developing countries, the demand for protein from animal sources will be

¹ In this report, the term “livestock” refers to domestic animals such as cattle, swine, horses, sheep, and chickens that are raised on a farm for use or profit.

unprecedented, especially in developing countries, and will require a “livestock revolution” (Delgado et al., 1999).The Food and Agriculture Organization of the United Nations (FAO) estimates that feeding the world population in 2050 will require a 58% increase in meat production to produce a total of 470 million tons to meet the demand for animal protein (FAO, 2009), which would require exceptional growth in the production of animals and animal products.

Role of Research and Development in Animal Productivity

The United States has been fortunate in its abundance of natural resources to support agriculture, but recent success in the agricultural sector has been based on unparalleled advances in effective research that have resulted in remarkable gains in agricultural productivity. The ability to apply key research findings and technologies to enhancing the agricultural productivity has improved animal productivity and enabled farmers to produce more meat and milk products to meet growing demand while reducing resource use. For instance, increased animal productivity has enabled an increase in total milk production through increased production per cow even though the number of US dairy herds has decreased. The United States has also made progress in eliminating many of the livestock and poultry diseases that are still found in animal populations in other countries. However, there is concern about the future levels of investment in agricultural research and development that are required for continued scientific advances that can benefit US consumers and businesses and that can sustain our ability to be a global leader and producer.

US investment in an effective animal-health infrastructure, at both the state and national levels, has been instrumental in improving the health of our livestock and poultry populations and in protecting them against the incursion of foreign animal diseases (FADs) and the spread of endemic animal diseases. Through effective federal-state partnerships, animal-health officials continue to reduce and eliminate costly animal diseases, such as brucellosis, tuberculosis, pseudorabies, and exotic Newcastle disease. As a result, US producers have been able to focus on raising livestock and poultry with higher productivity values compared to those of other countries, where food animals are produced under the burden of diseases and parasites that greatly decrease their productivity, threaten public health through of zoonoses (diseases transmitted between humans and animals), and reduce food security.

Vulnerability of Animal Agriculture

US consumers have a stable, abundant, nutritious, and safe food supply. The stability of the food system is put at risk in part because of factors that drive the emergence of disease and disease vectors, and also due in part to factors that intensify and expand the interface between humans and animals and their prod-

ucts (IOM and NRC, 2009). Socioeconomic factors that affect disease emergence include increasingly globalized trade and changes in the environment that increase the movements of people, animals, and disease vectors (IOM and NRC, 2009). The movement of people, global travel and trade, the complexity of global food systems, and the ease with which pathogens circumnavigate the globe contribute to a significant threat to animal health and public health in that many animal diseases are also capable of infecting humans. Food animals are being produced in more concentrated and integrated systems, and this may also be a factor that could affect health and disease transmission.

Consequences of a Foreign Animal Disease or Zoonotic Disease Incursion

Disruptions in the food system could have catastrophic economic repercussions for US producers and for the systems and enterprises associated with animal agriculture. A major FAD or zoonotic disease event could result in economic losses of billions of dollars, including losses to producers, agricultural and food sector employees, consumers, and taxpayers; damages to landscape and environmental resources; and potential public-health costs associated with zoonotic diseases. Additional concerns include animal suffering, human psychological costs, and potential loss of public confidence. A large variety of significant losses may arise, depending in part on the event’s location, on post-event management, and on international trade responses to the event. It is conceivable that large capital losses would materialize, as when many businesses in a region are forced to exit permanently. Recent experiences in the UK and elsewhere have dealt with bovine spongiform encephalopathy (BSE) and foot-and-mouth disease epidemics, which provide examples of the magnitude and breadth of possible consequences resulting from disease outbreaks.

Studies on the general matter have focused on foot-and-mouth disease, in part because this disease is of great concern and in part because several significant foot-and-mouth disease events have allowed modelers to better appreciate and formulate the more critical aspects of loss determinants. The 1997 foot-and-mouth disease outbreak in Taiwan undermined the viability of the island’s pork production sector, which was heavily dependent on exports to Japan (Blayney et al., 2006). The UK experienced a severe foot-and-mouth disease outbreak in 2001 that lasted 221 days and resulted in 2,026 infected premises (UK-Defra, 2002). In controlling the foot-and-mouth disease outbreak, UK officials destroyed more than 6 million animals (including more than 1.2 million infected and more than 5 million healthy animals to prevent disease spread) at an estimated cost of US$10.7-11.7 billion (Thompson et al., 2002) where the rural recreation sector also suffered large losses (Blake et al., 2003). In 2010, South Korea experienced its worst foot-and-mouth disease outbreak, which resulted in the culling of nearly 10 million swine and almost 3 million cattle and cost more than US$1.8 billion (USDA-FAS, 2011).

Several economic studies have considered a foot-and-mouth disease outbreak in the United States. Ekboir (1999) estimated that the cost of a foot-and-mouth disease outbreak in the state of California alone would be $8.5-13.5 billion, of which about $6 billion would be attributed to an embargo on US meat exports. Paarlberg et al. (2002) estimated that a foot-and-mouth disease outbreak in the United States similar to the one that occurred in the UK in 2001 could generate US farm-income losses of $14 billion. Zhao et al. (2006) considered a foot-and-mouth disease event of non-defined geographic origin and estimated total losses in the order of $20 billion, or possibly much more if traceback is poor. The US bovine production and produce sectors are open and dispersed in form, and traceability for disease events has been problematic in the past. Carpenter et al. (2011) have integrated a spatial stochastic epidemic model into an economic analysis to conclude that a foot-and-mouth disease outbreak originating in a large California dairy herd could reasonably exceed $20-30 billion in economic losses.

Other FADs and zoonotic diseases such as African swine fever, BSE, and highly pathogenic avian influenza could also result in large and varied losses. The global severe acute respiratory syndrome (SARS) epidemic in 2003 demonstrates the effects of a disease that originated in animals and resulted in severe losses to individuals and a large number of business sectors. Thus, whether they directly affect the health of animals only or whether they are transmitted from animals to humans, disease outbreaks have a major impact on agriculture, food security, and socioeconomic well-being.

CRITICAL INFRASTRUCTURE TO PROTECT ANIMAL HEALTH

The American public has come to expect a continuous, safe, and relatively inexpensive food supply. To maintain the status quo, it is critical for the United States to have an effective and integrated animal-health infrastructure in place that is commensurate with protecting an animal agriculture enterprise with annual revenues of $165 billion (USDA-ERS, 2012a). Such an infrastructure is important for preventing the entry of FADs, rapidly detecting and responding to disease threats, implementing a response and recovery plan, training a workforce for routine and emergency situations, ensuring excellent diagnostic services, and maintaining an effective research and development program.

The recent economic recession and movements toward smaller government have resulted in a substantial reduction in the state and federal animal-health workforce and have decreased funding for research and diagnostics. At the same time, the Plum Island Animal Disease Center (PIADC)—the high-biocontainment laboratory that has served as a critical linchpin for safeguarding animal health by supporting diagnostics and research related to FADs—has continued to age well past its expected lifespan. The Department of Homeland Security (DHS) has determined that a new facility is necessary to replace the aging PIADC. However, in the current economic climate, DHS is facing a challenge in identifying

adequate resources to fund construction of a new laboratory as currently designed.

With that backdrop, new problems have emerged with respect to the commitment to and the resources necessary for addressing growing threats and for addressing the vulnerability of animal agriculture to FADs. The challenges have grown progressively more complicated with the shifting of the US financial and political landscape. The United States faces new realities for setting priorities, determining tradeoffs, and making key decisions.

The convergence of increased threats and consequences of animal disease epidemics, the need to have a diagnostic and research system commensurate with addressing the threats, and the reality of reduced resources to accomplish both have created four critical issues and decision points.

•  First is the issue of reconciling the capital cost of a state-of-the-art laboratory for agricultural biodefense while investing in critical research. The need for both is clear, but providing funds for both may not be feasible.

•  Second is the dilemma that centers on the need for continuing research and diagnostic capacity at the current facility while constructing and transitioning to a new facility. The expense of building one facility while maintaining another in order to maintain current capacity adds further budget pressure for 10-12 years.

•  Third, the extended timeline from initial project approval through final construction and commissioning may be more than a decade, and this creates a dilemma in planning. Current disease threats may not be indicative of future disease threats, and the technological tools that are available for countering current disease threats may change rapidly over time and become outdated. That creates a challenge for ensuring that the new facility’s capabilities and capacity are consistent with future needs and adaptable in the face of technological advances.

•  Fourth, the present budget constraints that have led to the present committee’s charge may persist. If they do, government programs and services that have received support in the past may need to be transformed and reevaluated, and high-priority programs and facilities may need to be supported by alternative funding strategies. The latter requires innovative and strategic planning to make it possible to protect a national asset from FAD and zoonotic disease threats.

ANIMAL DISEASES OF CONCERN

In assessing the spectrum of livestock and poultry disease threats, the committee examined past high-priority diseases of concern to the US Department of Agriculture (USDA), current livestock and poultry notifiable-disease lists, the results of deliberations on disease threats that have occurred in recent years, and previous National Research Council reports. A broad array of diseases can be

considered threats to livestock and poultry, and many of them are also zoonoses of human health importance. The overlap among various studies and priority assessments is extensive. Most diseases that were previously identified as having high priority continue to remain a priority. Diseases that have newly emerged or that constitute threats because of potential intentional introduction have been added to the list of disease threats. Many threat-assessment studies have been conducted, but they typically have focused on specific disease types and used a wide variety of methods and so are not easily comparable. The committee was unaware of any threat assessments that used a common, quantitative, systematic, and comprehensive approach that would allow valid meta-analysis for setting priorities among disease threats. Integrating various components— such as transmission and spread models, economic effects, social effects, and effects on human and animal health—into a single assessment is difficult and has not typically been done. That gap in knowledge poses a serious challenge to systematic priority-setting among threats posed by diseases and has led to reliance on subject-matter experts for guidance on priorities for livestock and poultry disease threats on an ad hoc basis.

Diseases that have historically been considered by USDA to have the highest priorities for surveillance, vaccine research, and diagnostic test development have been infectious diseases of livestock and poultry that are exotic to the United States and endemic diseases that are regulated as a part of control and eradication programs, otherwise known as “program diseases”. The program diseases have included endemic diseases such as brucellosis, tuberculosis, pseudorabies, and avian influenza and FADs such as foot-and-mouth disease, classical swine fever (CSF), highly pathogenic avian influenza, and exotic Newcastle disease. In the last 15 years, of the 3,149 investigations that USDA conducted of possible FAD or emerging disease incidents, only a small percentage were confirmed as FADs or emerging diseases (USDA-APHIS, 2012). In 2011, USDA conducted 327 FAD investigations which resulted in only one confirmed FAD (USDA-APHIS, 2012).

The World Organisation for Animal Health (OIE) maintains a list of FADs and zoonotic diseases that can significantly impact animal populations and trade, and many of the same USDA program diseases appear on the OIE list. Since 2001, the threat of biological terrorism has focused on the intentional introduction of animal diseases, and there is substantial overlap among the threat agents identified (see section on “Agroterrorism” later in this chapter). These disease agents are also considered select agents and are listed in the National Select Agent Registry program overseen jointly by USDA and the Centers for Disease Control and Prevention (CDC). Finally, the identification of previously unknown pathogens (such as SARS virus) and variants of known agents (such as pathogens with newly arising antimicrobial resistance patterns [Jones et al., 2008]) has placed increased attention on the effects of emerging disease threats, some of which are zoonotic and raise public-health concerns.

In 2012, the OIE list included 116 animal diseases, of which 25 occur in multiple animal species, 14 in cattle exclusively, 11 in sheep and goats, 11 in

equine, 7 in swine, 12 in birds, and 36 in other species (lagomorphs, bees, fishes, mollusks, crustaceans, and amphibians). The diseases that occur in livestock and poultry are provided in Table 2-1.

In addition to the list of reportable diseases, OIE member countries are expected to notify OIE when a new disease agent is identified or when the epidemiology of a known infectious agent changes significantly. That in effect creates the need for a system that can detect and characterize newly arising disease threats in member countries.

TABLE 2-1 World Organisation for Animal Health List of Animal Diseases, 2012. (Boldface indicates zoonotic diseases; underlining indicates FADs).

SOURCE: OIE (2012).

NOTES: ^aSome viral serotypes of bluetongue and vesicular stomatitis are endemic in the United States; others are considered exotic.

^bExotic Newcastle disease virus is technically zoonotic, as it can infect humans and cause mild clinical illness such as conjunctivitis and oral lesions (Chang, 1981; Alexander, 2000).

In 2004, the White House Office of Science and Technology Policy and the RAND Corporation convened a blue ribbon panel to assess the threat of biological terrorism to livestock and poultry. The results of the panel deliberations on high-priority and medium-priority threats are provided in Table 2-2.

TABLE 2-2 Priority List of Diseases of Concern. (Boldface indicates zoonotic diseases; underlining indicates FADs).

SOURCE: Kelly et al. (2004).

Of note in Table 2-2 is the inclusion of Nipah virus, Hendra virus, and Rift Valley fever virus as high-priority pathogens, which are also zoonotic agents, and the inclusion of Venezuelan equine encephalomyelitis viruses, pox viruses, and unknown or emerging diseases as having medium priority.

The United States has also compiled a list of 17 diseases or agents for the national vaccine stockpile that are considered threats in connection with intentional or accidental introduction (Table 2-3). This list reflects agents for which immediate vaccine preparedness and deployment is prioritized, and includes agents not found on the OIE list (such as Hendra and Akabane viruses). All but eastern equine encephalomyelitis and Q fever are considered FADs, and many are zoonotic.

DIAGNOSTIC NEEDS

In 2002, in conjunction with the development and implementation of the National Animal Health Laboratory Network (NAHLN), eight agents were identified for which deployment of rapid and accurate diagnostic tests had high priority: foot-and-mouth disease virus, CSF virus, highly pathogenic avian influenza virus, exotic Newcastle disease virus, African swine fever virus, rinderpest virus, lumpy skin disease virus, and Mycoplasma mycoides subsp. mycoides SC (bovine biotype), the causative agent of contagious bovine pleuropneumonia. In

TABLE 2-3 Most Serious Animal Disease Threats in the United States Listed on the National Vaccine Stockpile List. (Boldface indicates zoonotic diseases).

addition, DHS conducted a series of workshops examining the needs for livestock and poultry disease screening tools. The results of those workshops (see Box 2-1), the latest of which occurred in May 2012, have helped to identify agents for which diagnostic test development is of highest priority and have directed the development of diagnostic test formats and sample types that will be of the greatest value for disease detection and response.

The workshops provide a current perspective on the high-priority research needs identified by stakeholders for diagnostic test development to counter disease threats. A facility in which to conduct such research will require high-level biocontainment for initial proof of principle and test development.

As indicated in Tables 2-1, 2-2, and 2-3, many agriculturally important diseases are also of human health importance (zoonoses). Recent examples include highly pathogenic avian influenza A(H5N1), which has a 60% case-fatality rate among recognized human infections that have occurred primarily in Asia since 2003. As of May 2, 2012, the World Health Organization received reports of 603 confirmed human cases and 356 deaths due to highly pathogenic avian influenza A(H5N1) (WHO, 2012). Many zoonotic agents, such as eastern and western equine encephalomyelitis viruses, are endemic within the United States, and others, such as West Nile virus, are recent introductions. Some zoonotic pathogens—such as Crimean-Congo hemorrhagic fever, Nipah, and Hendra viruses—require biosafety level 4 containment for their safe and secure handling. Many are recognized as potential bioterrorist agents and are listed as “crossover agents” in the Select Agent Program.

AGROTERRORISM

A particular route of entry of FADs that needs to be considered is the deliberate introduction of a native or bioengineered disease agent for the purpose of destabilizing food sources or generating fear. Agroterrorism was the focus of several homeland security presidential directives (HSPD-5 and HSPD-7 in 2003 and HSPD-9 in 2004) and of Congressional Research Service reports (2001, 2004-2007). The Strategic Partnership Program Agroterrorism Initiative was established in 2005 by the Federal Bureau of Investigation (FBI), DHS, USDA, and the Food and Drug Administration (FDA) to include industry partnership. USDA and FDA have Web sites dedicated to the issue (see FDA, 2008; USDA, 2012), and the FBI recently focused attention on agroterrorism in a 2012 FBI Law Enforcement Bulletin (Olson, 2012). The latter notes that the terrorist threat analysis now recognizes the increased possibility of smaller, less dramatic, independent attacks, which would include agroterrorism.

If a potential intentional release is reported, health authorities notify USDA’s Office of the Inspector General or FDA’s Office of Criminal Investigation, which will contact the National Operations Center. If it is determined that the event is terrorism-related, those offices will contact the local FBI weapons of mass destruction unit to launch a full-scale investigation. Aspects of the investigatory process include continued surveillance of the outbreak, maintenance of chain of custody, and identification of appropriate laboratories for sample submission. The Integrated Consortium of Laboratory Networks established by the FBI and CDC comprises the Laboratory Response Network, the Food Emergency Response Network, the NAHLN, and the National Plant Diagnostic Network. As with all response networks, pre-established working relationships facilitate a preliminary cross-check inquiry to identify terrorist attacks in the agriculture sector.

SUMMARY

Numerous National Research Council studies in the last 10 years have assessed disease threats to animal health and public health (NRC, 2005a,b; IOM and NRC, 2009), so the present committee did not attempt an exhaustive reconsideration of the broad array of disease agents that can affect animal agriculture. But the committee emphasizes that the drivers of disease emergence in our global society have not changed, which could give rise to novel agents or to known agents that are exotic to the United States. In general, the committee agrees with conclusions of previous analyses yet emphasizes the need for more cross-cutting, integrated threat assessments that consider multiple variables in a quantitative manner. Foot-and-mouth disease remains a disease of high priority in animal agriculture because of its propensity to spread rapidly and its potentially devastating economic consequences. But foot-and-mouth disease is not the

only threat, and a comprehensive system to counter such threats in animal agriculture is vital. In Chapter 3, the committee describes an ideal system for addressing such threats and identifies critical core capabilities necessary in a national laboratory.

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