Editorial: Foreign animal disease

Non refereed

Risks and responsibilities

Paul J. Armbrecht, DVM, and the AASV FAD Committee

1103 West Main, Lake City, IA 51449. Tel: 712-464-8911; Fax: 712-464-8016

Armbrecht PJ. Foreign animal disease J Swine Health Prod. 2001;9(6):293-294.

One function of the United States Department of Agriculture (USDA) and the Animal and Plant Health Inspection Service (APHIS), an agency of the USDA, is to protect the health status of United States agricultural animals. An exotic or foreign animal disease (FAD) is defined as an important transmissible disease of livestock or poultry believed to be absent from the United States and its territories. Animal and Plant Health Inspection Service officials work with state animal health authorities and veterinarians to protect the long-term health and profitability of United States animal agriculture. If an FAD does enter the United States, these officials work to rapidly control and eradicate the disease.

Foreign animal diseases are considered a threat to the United States when they significantly affect human health, or when there is appreciable cost associated with control or eradication of disease in livestock. In addition to disease control costs, the most immediate consequence of an FAD in the United States is the loss of exportmarkets. As the percent of total production destined for export grows, the impactof an FAD outbreak also grows. The 1997 outbreak of foot-and-mouth disease in Taiwan was devastating for that country's pork industry, as 4 million pigs were destroyed and virtually all export markets were lost. Classical swine fever, formerly known as hog cholera, caused the same type of industry catastrophe in the Netherlands in 1997. Foot-and-mouth diseaseis currently causing similar consequences in the United Kingdom and the European Union. In addition to the loss of markets, FADs such as classical swine fever, foot-and-mouth disease, and highly pathogenic avian influenza can cause high death rates, severe illness, and (or) production losses. Loss of production increases the domesticcost of food products.

The world is moving toward increasingly open market access. Free trade agreements, such as the North American Free Trade Agreement (NAFTA) and the General Agreement on Trade and Tariffs (GATT), allow restriction of trade only if there is a valid human or animal health risk to the importing country. This situation allows for the increased flow of animals and animal products into the United States, and the requirement and responsibility for evaluating and monitoring health risks increases accordingly.

Commercial airlines report that the number of international travelers arriving in the United States has nearly tripled in the last 20 years. Contaminated foodstuffs brought into the United States can serve as the source of an FAD. An infection at one premise can involve hundreds or thousands of animals. Frequent and rapid interstate movement of animals occurs routinely in the United States, allowing an infectious agent to spread into many states before the source herd shows clinical signs of disease. Importation of some non-production animals, such as reptiles, can introduce ticks or other disease vectors that transmit FADs to mammals, including livestock.

Natural selection pressure is causing infectious disease agents to adapt and change. A recent example is the swine-specific strain of foot-and-mouth disease virus in Taiwan. As production practices in US animal agriculturecontinue to change, geneticresistance or susceptibility of US livestock also changes.

Disease surveillance is very important for early FAD detection and for accurate risk analysis. The USDA-APHIS constantly explores new methods for monitoring the health of the US livestock and poultry population. Improved educational programs and awareness by all segments of the livestock industry are becoming much more important. As traditional program diseases such as brucellosis and tuberculosis (and very soon pseudorabies) are eradicated and the current surveillance funding decreases, new surveillance systems for disease monitoring will be needed.

The USDA, state animal health officials, universities, diagnostic centers, and everyone associated with the livestock industry must recognize the changing risks and threats. Educational programs for producers and herd veterinarians are becoming essential, as these people are the first line of defense. Protecting the livestock and poultry industries of the United States from FADs involves four basic principles or phases of emergency management: Prevention, Preparedness, Response, and Recovery. Effective support and implementation of these principles depends on the cooperation of everyone from governmental authoritiesto industry personnel and the traveling public.

Prevention

Responsibility for preventing the introduction of an FAD into the United States has been primarily assigned to USDA-APHIS Veterinary Services. Other organizations within APHIS administer laws and regulations pertaining to importation of animals or animal products. Inspection of luggage, cargo, and passengers is conducted by the Plant Protection and Quarantine (PPQ) service of the USDA. Veterinary Services cooperates with other agencies to ensure that materials imported from foreign countries are free of certain disease agents or vectors.

Preparedness

Training and education of livestock owners, private veterinarians, and industry personnel are the responsibilities of state animal health officials and USDA-APHIS. Thus, EVERYONE has a stake in being aware of and prepared for suspicious health problems that could indicate an FAD.

Response

When the suspicion of an FAD is reported to state officials, FAD diagnosticians are called upon to investigate the herd or flock. Specimens are collected for submission to the appropriate laboratory. If an FAD is confirmed, the secretary of the USDA may declare an emergency which releases federal funds to be used for control and (or) eradication of the disease.

Recovery

After the FAD is eradicated, more intense surveillance is undertaken to be certain that the FAD has been completely eliminated. Review of prevention procedures reduces the risk of disease re-entry.

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Foreign Animal Disease Training School: A practitioner's perspective

Paul J. Armbrecht, DVM

FAD School

In January and February of 2000, I was fortunate to be invited to attend a Foreign Animal Disease (FAD) training course offered at the Plum Island Animal Disease Center by the Foreign Animal Disease Diagnostic Laboratory, one of the National Veterinary Services Laboratories. The Plum Island Animal Disease Center, located on Plum Island, New York, off the coast of Long Island, is a former military post now owned and occupied by the USDA. This facility houses research and diagnostic facilities for foreign animal diseases. The training school has been used mainly to train state and district veterinarians, laboratory diagnosticians, and federal animal health employees in the recognition of FADs. Through the efforts of NPPC and AASV, the recent program, with emphasis on foreign swine diseases, was made available to swine practitioners. I was honored and humbled to have been accepted to attend this training program. However, it did require me to be away from my practice for more than 3 weeks. Because of the nature of diseases that were observed, all participants were required to stay away from birds and cloven-hoofed animals for 5 days after the 2-week program.

Why is there concern about FADs?

The United States livestock industry is at risk to FADs because of high animal density and high susceptibility (zero immunity!). World trade agreements have fostered and created global markets for many goods, including foodstuffs of animal origin.World travel occurs regularly among people who have had direct contact with animals (ie, on safaris, at zoos, in pet stores, on livestock farms). People may transport or ship food products that put livestock at risk of exposure to FADs via waste discarded from planes or ships, or by individuals. Uncooked food products, such as sausages, are high-risk items that may harbor FAD agents. These materials can and do enter the United States illegally and threaten the health of the livestock population. Thus, producers and practicing veterinarians must be aware of the risk of FADs and of the correct procedures for reporting a suspected FAD and for requesting assistance in dealing with the situation.

Many FADs have clinical signs very similar to common health problems. Classical swine fever and paramyxovirus (blue eye) can produce signs similar to those associated with salmonellosis, swine influenza virus, porcine reproductive and respiratory syndrome, or circovirus. Other FADs, such as foot-and-mouth disease, vesicular stomatitis, and African swine fever, may be virtually asymptomatic because of variation in the virulence of the disease and the effects of environment. The risk of FAD entering the United States is real! We all must cooperate and understand the importance of recognizing unusual health problems or disease signs, submitting tissues to appropriate laboratories, and involving the appropriate authorities in a timely manner. This task will involve producers, regulatory officials, and private practitioners. Coordination of activities and the educational process can be a cooperative effort of university groups, industry, and state and federalofficials.

What about Plum Island?

Many researchers at the facility had a misperception of the United States pork industry. While swine veterinarians realize that 5 to 7% mortality is common in finishers, and that pigs often do not receive individual veterinary care, the Plum Island personnel believed that diagnostics are performed frequently on any and all dead pigs. Researchers and many government employees do not understand that "pigs are on wheels" and are moving daily. They talked about the "night of lights" in the Netherlands, when the classical swine fever outbreak occurred and producers transported pigs at night to avoid enforcement of restricted movement. The state of Iowa alone receives nearly 1 million pigs monthly in addition to the intrastate movement of another million. Thus, pigs are on the move and the risk of an FAD outbreak is amplified.

Foreign animal diseases studied and observed during the training school were exoticNewcastle disease and highly pathogenic avian influenza of poultry, foot-and-mouth disease, classical swine fever, African swine fever, heartwater disease, African horse sickness, rinderpest, sheep pox, and related pox viruses. These diseases were observed in live animals, and the progress of the disease was recorded daily. All animals were necropsied at death or were euthanized for tissue collection. Each day classes were held for 2 to 4 hours to review the many other diseases that occur around the world. Because of the nature and the biosecurity risk of these infectious agents, numerous showers were taken each day and clothing was discarded. All animal tissue at the facility is disposed of by incineration. The daily trip to the island was by boat. Rough seas apparently are common during the winter because of the "nor'easters", which are storms coming from the northeast. High waves caused some people to experience classical seasickness daily, which made class long and miserable!

This experience was special because it allowed me to be involved with the training process and to provide some of the teachers and researchers with information about the pork industry. I learned about foreign animal diseases and realized that diagnostics will be vitally important to differentiate FADs from commonly seen diseases. Since our industry is at risk, everyone with a stake in the industry must cooperate to become better educated about FADs and more familiar with the FAD response and reporting system. I encourage other swine practitioners to attend this school.