Animal health officials define an exotic or foreign animal disease (FAD) as an important transmissible livestock or poultry disease believed to be absent from the United States and its territories that has a potential significant health or economic impact. The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) is working vigilantly with State animal health officials and veterinary professionals to identify, control, and eradicate these animal diseases and diminish their impact. As a preface to the updated disease information, this introductory article will provide an overview of the ways in which FAD's may impact U.S. consumers and producers. It will also highlight the new challenges facing those involved in prevention, management, and recovery from FAD threats to the United States.

Impacts of FAD's on the U.S. Economy

Foreign animal diseases are considered a threat to the United States when they significantly affect human health or animal production and when there is an appreciable cost associated with disease control and eradication efforts. Diseases such as hog cholera, foot-and- mouth disease (FMD), and highly pathogenic avian influenza (HPAI) can cause high death rates or severe illness and production losses. This loss of productivity can increase the cost of food products obtained from those animal sources. For example, during the 1983-84 outbreak of HPAI, the average cost of one dozen eggs increased by 5 percent (1). McCauley et al. predicted that the price of beef would increase by $0.19 per pound because of an outbreak of FMD (2). Other diseases such as tuberculosis (TB) and brucellosis affect human and animal health. These two diseases, although very prevalent in other countries, will soon be eradicated from U.S. domestic livestock and will thus become exotic.

To protect the long-term health and profitability of U.S. animal agriculture, incursions of a FAD must be rapidly controlled. In the United States, control usually means disease eradication. These eradication efforts can present significant short-term costs to industry and government. For example, in 1983-84 the control and eradication of a highly pathogenic avian influenza outbreak cost the USDA $60 million. In the final stages of hog cholera eradication (1971-1977), the U.S. government spent $79 million (3).

In addition to control costs, one of the most immediate and severe consequences of a FAD occurrence in the United States will be the loss of export markets. U.S. animal agriculture is becoming more dependent on exports. The long-term strategic plans of these industries call for increasing the amount of goods sold abroad. As the percentage of total production destined for export grows, the impact of a domestic FAD outbreak also grows. Other countries will not allow the importation of animals or animal products that pose a risk to their industry. In 1997, the total value of exported U.S. animals and animal products exceeded $7 billion: $2.3 billion in poultry, $1 billion in pork, and $2.6 billion in cattle and cattle products. Theoretically, the long-term trade impacts of a FAD occurrence can be reduced by applying regionalization concepts. A country could, during a FAD outbreak, recognize specified regions of the United States as affected with the disease. The remaining unaffected areas might be free to continue exporting. However, it would take considerable time to have these regions identified and other regions certified as disease-free. In the meantime, all trade in that commodity would be stopped.

New Challenges for the Management of FAD's

As we move into the 21st century, many new issues and factors are affecting FAD prevention, control, management, and recovery. These factors include free trade agreements, free trade blocks, regionalization, increased international passenger travel, intensification of animal production, the constant evolution of infectious agents, and the uncertain impact of biotechnology and bioterrorism.

Evidence is accumulating that these factors are having an impact. For example, hog producers in Taiwan recently experienced a devastating outbreak of FMD for the first time since 1929. Over four million animals were destroyed. Virtually all export markets were lost. The Netherlands recently sustained an outbreak of hog cholera that resulted in major export losses of 65 percent of their production. Other countries in the European Union struggle to eradicate hog cholera. As this book goes to press, hog cholera is active in the Dominican Republic, which is situated only 150 miles from the continental United States.

The world is moving toward more open market access. Free trade agreements such as GATT (General Agreement on Tariffs and Trade) and NAFTA (North American Free Trade Agreement) stipulate that trade in animals and animal products should only be restricted if there is a valid human or animal health risk to the importing country. To stop trade, the importing country must show, with a scientifically valid analysis, that a risk exists. This policy will increase responsibility for the United States to evaluate risks carefully . It also will probably increase the flow of animals and animal products into the United States.

A related element of free trade agreements is the concept of regionalization. As an importing country, the United States is required to evaluate geographic regions of potential importers. More effort and information will be required for the United States to evaluate the risk of a disease from a region that may be smaller than or larger than an area defined by political borders. The United States must have some methods to evaluate the security of the region's boundaries. The acceptance of regionalization puts increased pressure on the United States to remain vigilant for the presence of disease at home and in various countries exporting or hoping to export, to our shores. Examples of regionalization include recognizing the northern U.S. states as Bluetongue free, northern Spain as free from African horse sickness, and portions of Argentina as FMD free.

Around the world countries are joining into free trade blocks. They hope these alliances will give them a competitive advantage against other trading blocks such as the European Union and the NAFTA countries. Problems arise as livestock or animal products are allowed to move freely within these blocks because we may not always know the origin of the products we import.

The volume of international passenger travel is steadily increasing. In 1980, 20 million passengers arrived in the United States on international flights. In 1995, this number rose 131 percent to 47 million (4). The airline industry expects this trend to continue. International travelers may unknowingly bring contaminated animal products from FAD infected countries. Contaminated foodstuffs have often served as a source of a FAD in the United States and other countries (5).

As the world population grows and animal production intensifies, the risks and impacts of FAD incursions increase. Today, infection at one premises can affect 300,000 laying hens, 100,000 hogs, or 100,000 feedlot cattle. When one company owns a large number of animals, frequent and rapid interstate movement occurs. This movement can spread infection across many states before clinical signs are manifest in the source herd.

Lastly, the infectious disease agents and vectors are changing. For example, as the importation of reptilian pets increases, potential disease-transmitting vectors such as Amblyomma ticks are finding new routes of entry. Also, natural selection pressures predict that the FAD of the next decade will be different from the last. Recent examples include the swine-specific FMD virus in Taiwan, Salmonella DT104, and Salmonella enteritidis. Actions and information that accurately prevented disease or predicted risk in the past may not be effective in the future. Around the world, new agents never before a threat to U.S. agriculture have become an important human health or economic concern. Examples include bovine spongiform encephalopathy and porcine reproductive and respiratory syndrome. Today's new emerging disease may be tomorrow's significant exotic disease.

U.S. Responses to Changing Exotic Animal Disease Threats

The Animal and Plant Health Inspection Service has taken the lead in publishing a rule on regionalization expectations. This rule will contribute to international negotiations on animal trade. To define optimal methodologies for conducting risk analyses, APHIS is working with universities, consultants, and the Economic Research Service (ERS). Also, APHIS is beginning to educate animal health officials, the animal agricultural industry, and our trading partners about the concepts and impacts of regionalization.

Disease surveillance data are a critical element for early FAD detection and for accurate risk analyses. Consequently, APHIS is constantly exploring different methodologies for monitoring the health of the U.S. livestock and poultry population. As traditional program diseases such as tuberculosis and brucellosis are eradicated and funding decreases, new surveillance systems will be needed. The U.S. animal health surveillance systems are therefore being reviewed by APHIS to achieve the highest efficiency and breadth without compromising disease detection abilities. Also, APHIS is working with our Latin American trading partners to design feasible surveillance systems for the region. In protecting American agriculture, APHIS is playing a key role in collaborating with international health organizations such as OIE (Office of International Epizootics), IICA (Inter-American Institute for Cooperation on Agriculture), FAO (Food and Agriculture Organization), and others to harmonize trading regulations, risk analysis methods, disease surveillance, and diagnostic methods.

The USDA, state animal health officials, universities, and the animal agricultural industry are taking many steps in response to these changing threats and risks. The diagnostic laboratory system is constantly improving and applying state of the art technology for FAD diagnosis and differentiation. International contacts are used to maintain awareness of disease occurrence. Consolidating the Agricultural Research Service (ARS) and APHIS and remodeling laboratory facilities at Plum Island will strengthen the opportunities for collaboration on FAD reseach and diagnostic programs.

The emergency management plan is being revised with greater involvement of partners to ensure rapid detection and response. These efforts are discussed in Part III, Protecting Livestock and Poultry Industries from Foreign Animal Diseases, in this publication. Veterinary Services (VS) has downsized just like other U.S. government agencies. In that process, we have gone from four regional emergency response teams to two. However, in doing this, we have also created small Rapid Response Teams that can quickly be deployed to investigate possible FAD outbreaks. Additionally, VS is working more with State departments of agriculture, private veterinary practitioners, and other veterinary specialty groups to formulate better responses to these new threats. Moreover, VS has been examining the distribution of specially trained diagnosticians to determine any needed changes to improve the availability of these individuals. Key diagnosticians to be sent to outbreaks in other countries have also been indentified by VS. This adds to our current knowledge base of the disease outside the laboratory and of the real-life problems involved in control and eradication.

Finally, VS has made efforts to create a manageable data base to collect information on all potential FAD investigations. This begins by having the diagnostician corps enter the most accurate and inclusive data into a computer data base. The future goal is to be able to look at trends and give values back to the reporting producer and veterinary practitioner. The trends may help VS to distribute and train its corps of diagnosticians better. It is hoped that the returned added value will stimulate more reporting by the private sector.

Conclusion

Exotic or emerging animal diseases continue to threaten the health and productivity of U.S. livestock and poultry. All of those with the potential of being affected are working to manage these threats by responding to these new challenges.

Joan M. Arnoldi, D.V.M., M.S
Deputy Administrator, APHIS, VS

GUIDE TO THE LITERATURE

1. LASLEY, F. A., SHORT, S. D., and HENSON, W. L. 1985. Economic Assessment of the 1983-84 Avian Influenza Eradication Program. United States Department of Agriculture, Economic Research Service, National Economics Division. Washington, D.C.: U.S. Government Printing Office.

2. McCAULEY, E. H., AULAQI, N.A., NEW, J.C., SUNDQUIST, W.B., and MILLER, W. M. 1979. A Study of the Potential Economic Impact of Foot-and-Mouth Disease in the United States. University of Minnesota, United States Department of Agriculture.Washington, D.C.: U.S. Government Printing Office.

3. WISE, G. H. 1981. Hog Cholera and Its Eradication: A review of U.S. Experience. United States Department of Agriculture, Animal and Plant Health Inspection Service. Washington, D.C.: U.S. Government Printing Office.

4. National Transportation Statistics (NTS). 1997. http://www.bts.gov/btsprod/nts/acp.html. United States Department of Transportation.

5. Risk Assessment of the Practice of Feeding Recycled Commodities to Domesticated Swine in the U.S. 1995. United States Department of Agriculture, Animal and Plant Health Inspection Service. Washington, D.C.: U.S. Government Printing Office.

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