Overview of Foreign Animal Disease Investigation and Response

Protecting the nation's livestock and poultry industries, and therefore a large segment of the U.S. agricultural economy from TADs, involves four basic principles or phases of emer­gency management: prevention, preparedness, response, and recovery.

Although the details of the clinical signs and epidemiology of the TADs themselves are discussed in detail in other sections of this book, many additional references and resources are available to practicing veterinarians to help them keep apprised of the clinical presentation and importance of these diseases, as well as to whom to report suspected cases.

Prevention and Preparedness

Early recognition of a TAD may be difficult because some domestic diseases seen by veterinarians have similar clinical signs or presentations (e.g., foot-and-mouth disease [FMD]). Some TADs may have mild clinical signs that could allow them to spread undetected for a period of time. Examples of both domestic and transboundary vesicular or ulcerative diseases, which may be difficult to distinguish clinically in cattle, are presented in Box 47.5. A similar list for small ruminants is provided in Box 47.6. The increased likelihood and severe consequences of an introduction of a TAD into the United States requires private veterinarians to be continually vigilant for unusual emerging animal health conditions or situations. This requires veterinarians understanding how TADs may manifest and what clinical signs they may possess. Participation in continuing education programs aimed at increasing awareness of the clinical signs and presentations of TADs can facilitate this necessary awareness. Education and awareness should also be extended to livestock producers and their employees who will likely be the first individuals to recognize an unusual problem in the herd or flock they work with daily.

An important component of the prevention programs for TAD incursions is USDA's implementation of policies and procedures related to the importation of live animal species or products into the United States. These import rules vary

■ BOX 47.5

Diseases of Cattle That Are Difficult to Clinically Distinguish and May Resemble Foot' and-Mouth Disease^a

Foot-and-mouth disease

Vesicular stomatitis

Rinderpest

Bovine viral diarrhea

Malignant catarrhal fever

Bovine herpes mammillitis

Bovine papular stomatitis Pseudocowpox

Infectious bovine rhinotracheitis

^aReportable diseases are highlighted in bold.

■ BOX 47.6

Diseases of Small Ruminants That Are Difficult to Clinically Distinguish and May Resemble Foot-and-Mouth Disease^a

Foot-and-mouth disease Vesicular stomatitis

Malignant catarrhal fever Peste des petits ruminants Bluetongue—certain serotypes Contagious ecthyma (orf) Epizootic hemorrhagic disease

^aReportable diseases are highlighted in bold.

by animal and product, as well as by country of origin. USDA monitors the OIE reports of the world animal health status and continually updates these importation requirements accordingly. These requirements may dictate the quarantine and possible testing of specified animal species for specific periods before animals are allowed to enter the United States. As of 2018, there were three animal import centers, located in New York, Miami, and Los Angeles, through which animals could legally enter the country. USDA port veterinarians at the importation stations are responsible for the examination of the animals, their identification, and evaluation of health certificates and permits for accuracy. If the requirements are not met or the animals are found to be diseased, the animals may be refused entry, sent back to their country of origin, or humanely destroyed. Once it has been determined that an animal is healthy, all the test results are negative, and all the requirements have been met, then the animal can be released to its owner and the state of destination is notified of the animal's movement into that state.

Detection

Historically, border controls and import procedures have been largely effective in keeping TADs out of the United States. There is always the possibility that a TAD could appear in the United States by either unintentional or intentional means. Illegal importation of animals and animal products via other channels poses a significant risk to U.S. agriculture. The responsibility for rapidly detecting, confirming, and effectively responding to incursions of TADs is primarily that of USDA APHIS in cooperation with livestock and poultry owners, veterinarians in private clinical practice, and SAHOs. An additional challenge for early detection of TADs is that few ongoing active surveillance programs exist that routinely test for TADs in targeted, high-risk livestock populations or in conjunction with screening for clinically indistinguishable domestic diseases in state or regional veterinary diagnostic laboratories. Because many of the TADs can mimic domestic diseases, a TAD may not be properly identified for some time if the condition is believed to be a domestic disease problem and if it is investigated with only that limited differential in mind. Even a single day's delay in identifying a TAD can result in significantly greater disease spread or economic impact owing to the large amount of daily livestock movement in the United States. Prompt reporting, investigation, and diagnosis can prevent a TAD from spreading further, can reduce the overall economic impact of the event, and can reduce the likelihood that the disease may become endemic in a wildlife or arthropod reservoir.

The most likely person to initially suspect a TAD is the producer or private veterinarian called by the producer to investigate an unusual disease condition. It is critical that any time a TAD is suspected, it is reported to state or federal animal health officials for expedited investigation and testing as needed. The SAHO and federal veterinarians working for the USDA routinely work to increase awareness of such condi­tions and reporting information among the state's private veterinarians and livestock producers.

For TAD outbreaks to be detected quickly, any suspicious signs or situations indicative of a TAD must be promptly reported to a state veterinarian and the USDA federal veterinarian for the state where the animal resides so that a TAD can be confirmed or ruled out. Private veterinarians are knowledgeable regarding the occurrence of various domestic animal diseases in their practice area and the history of such diseases on their clients' farms and ranches. This type of historical information and a herd's vaccination and animal movement history are critical to assessing the likelihood of a suspected TAD. Working with the herd veterinarian and the producer, the investigating state or federal, specially trained, FADD will use the herd history and clinical investigation to assess the likelihood that the situation involves a TAD and to determine the appropriate sample(s) to collect, the method of sample delivery, and what precautions must be taken at the site while test results are pending. Samples are submitted to the National Veterinary Services Laboratories (NVSL) in Ames, Iowa, or to the Foreign Animal Disease Diagnostic Laboratory (FADDL) at Plum Island, New York, to confirm the presence or absence of a TAD. On the basis of initial TAD investigation findings, often before the laboratory has completed testing of the samples, state and federal officials in the affected state may take action to quarantine affected animals at the site of the suspected case, increase surveillance in the area, and initiate steps to gather further information to assess the situation and characterize and control the outbreak if necessary.

In the United States, select laboratories that are members of the National Animal Health Laboratory Network (NAHLN) under USDA Veterinary Services Memorandum 580.4 have been trained and proficiency-tested to run tests for TADs. With the permission of the NVSL Director, the SAHO, and the USDA Assistant District Director, these select NAHLN laboratories may run designated tests in parallel with NVSL or FADDL.

Response, Management, and Control

A TAD response will be conducted according to the guidelines set forth in the NRF. This response framework incorporates best practices and procedures from various emergency management disciplines. It integrates them into a unified structure that forms the basis of how the federal government coordinates with state, tribal, and local governments and the private sector during all national response incidents including animal disease outbreaks. Under the NRF, the USDA is the lead agency coordinating the protection of agriculture and natural resources. All national responses are conducted in accordance with NIMS, which established a national emergency response framework to allow local, state, tribal, and federal agencies to more efficiently and quickly work together in an emergency. The NIMS uses the ICS to organize the response. The ICS is designed to be expandable and to meet the needs associated with incidents of all sizes, to allow individuals from a variety of agencies to meld more efficiently into a common manage­ment structure, to be cost-effective by reducing duplication of effort, and to provide needed logistic, administrative, and operational staff. There are five main management functions in the ICS: incident command, operations, planning, logistics, and finance. Most veterinarians work in the operations or planning sections during a TAD response. The operations section is where the bulk of the tactical field work is conducted, such as diagnosis, biosecurity, surveillance, disinfection, and depopulation.

Once a TAD has been confirmed by the USDA, the notifica­tion and coordination process for all involved parties begins. This includes international, federal, state, tribal, local, industrial, and public stakeholders. Conference calls, electronic notification, and press conferences may be used to communicate key mes­sages. In addition, if agroterrorism is suspected, the Federal Bureau of Investigation and the Department of Homeland Security will be involved in the response efforts. If a zoonotic disease is suspected, the Centers for Disease Control and Prevention and state and local public health departments will also be involved. Federal officials will notify the OIE of the situation so that the international communities are made aware of the change in the nation's animal health status. Throughout the response, the goal will be to maintain accurate, timely communications regarding the status and progress of the eradication efforts.

Once the diagnosis of the initial case is confirmed, more information must be gathered to determine the true magnitude and extent of the situation. The species affected, history of the diseased herd or flock (including recent animal movements), and stage of disease in the affected animals will provide valuable information regarding the likely extent of disease. Outbreaks can be large or small, simple or complex, and localized or widespread. Timely development of situational awareness will be critical for mobilizing the necessary resources to effectively respond to the situation.

Tactical measures or procedures used to control an outbreak may include quarantine and/or animal movement restrictions; biosecurity; epidemiologic investigations; surveillance for disease in surrounding areas; vaccination, depopulation, or treatment of affected animals; carcass disposal; disinfection; vector control; and education campaigns. The exact approach to control will vary by disease, affected region, and extent of the outbreak. In rare cases, federal and state resources will be sufficient to respond to and control the situation quickly. However, if the outbreak is large or widespread, it will require the use of additional personnel resources.

In the past, when APHIS VS required temporary personnel to assist with disease eradication, it used the National Animal Health Emergency Response Corps (NAHERC),⁷ a roster of preregistered private veterinarians and animal health technicians, to assist with the control efforts. USDA plans to phase out NAHERC, but there are numerous opportunities at the local and state level to become trained and part of a response. Private veterinarians may be enlisted to examine herds or flocks for clinical disease, vaccinate animals, collect laboratory samples, perform necropsies, collect epidemiologic data, and euthanize infected animals. During the United Kingdom's 2001 FMD epidemic, many private veterinarians found that their practices had little business because their clients stopped using routine services as a precaution to reduce the chances that their farms would become infected. In other situations, veterinarians found that their clients' animals were lost (depopulated) as a result of disease control efforts. In many cases, these private veterinar­ians joined the U.K. FMD task force as temporary veterinary inspectors (TVIs) working on behalf of the British government to assist in the control of the epidemic. Veterinarians in the United States who may be interested in participating in an animal health emergency should contact the office of the SAHO for more information.

Business Continuity

TADs can have devastating effects on the animals, livestock industry, and U.S. economy. Eradicating the disease without destroying the industry is complex. The goals of a USDA response are to detect, control, contain, and eradicate the TAD in a manner that stabilizes animal agriculture, the food supply, and the economy while protecting public health and the environment. Another goal is to facilitate business continuity for noninfected animals and their products. The 2014-2015 highly pathogenic avian influenza demonstrated how science and risk-based approaches could be used to achieve this using the guidance in the Secure Poultry Supply Plans. Similar plans have been developed for FMD response for the dairy, beef, and pork industries. More information about the livestock Secure Food Supply Plans can be found at www.securemilk.org, www.securebeef.org, and www.securepork.org. Opportuni­ties exist for veterinary practitioners to help their clients prepare ahead of an outbreak to protect their animals and livelihood.

Recovery

The goal of recovery is to return the nation to a status equal to or better than what existed before a TAD outbreak. Full recovery can be a long and arduous process. Recovery activities include payment for animals and materials destroyed for disease control purposes, successful decontamination, clean-up and restocking of affected premises, renegotiation and reestablishment of international trading status, and government and industry's reassurance to consumers and the public that the outbreak has been managed successfully. The OIE's Terrestrial Animal Health Code sets the minimum standards that guide when a country may recover its disease-free status. The OIE standards, which are a key component to the resumption of international trade, serve to reassure the international community that trading with a previously affected country is now safe.

The ultimate cost of an outbreak for a country, its producers, affected industries, and the public can be quite high. Many indirect costs and impacts beyond those to the directly affected industries can be significant yet difficult to quantify.

Future of Foreign Animal Disease Detection and Response

A comprehensive review of the national framework for address­ing animal diseases was conducted by a committee assembled by the National Academies and published in 2005.8 The committee's findings and recommendations support the compel­ling need for significant changes to create a new future for animal health in the United States. Some of the key findings included the need for new tools for detection, diagnosis, and risk analysis and the expansion of the NAHLN's capabilities for both routine and emergency diagnostics. A report by the National Academies in 2012 described the many accomplish­ments of NAHLN as a timely surveillance and diagnostic component of early transboundary disease detection since its creation in 2002.9 Another improvement to diagnostic capabili­ties and research is the National Bio and Agro-defense Facility (NBAF), which is currently under construction, with the goal of being operational in December 2022.¹⁰ This state-of-the-art laboratory will replace the aging facilities at Plum Island and further enhance laboratory and discovery capabilities.

In 2005, the National Academies committee concluded that animal health has broad implications, ranging from the health of individual animals and the well-being of human communities to issues of global security and the adequacy of the global food supply. Planning carefully for the future is a significant need. That remains unchanged today. Given the changing nature of the risks to animal health in this country, it is unlikely that the current philosophy on how to protect animal health will be adequate in the future.

Extraordinary changes including continued globalization will continue to present new threats to U.S. agriculture and necessitate the continued vigilance of the veterinary and agricultural communities. Although state and federal govern­ments are working to provide more targeted, active surveillance programs, private veterinary practitioners, who on a daily basis provide health care to the national herd, will remain the core of the nation's early warning system for TAD surveillance. Therefore their awareness of TADs and willingness to serve in the critical role of being part of the nation's early warning system for TADs will continue to be a cornerstone of national defense against the intrusion and devastating impact of such diseases.