How Are We Protecting the U.S. Swine Herd?

By Beth Lautner, DVM, MS


The occurrence of a foreign animal disease (FAD) in the U.S. would be devastating to pork producers. Recent events, the Classical Swine Fever (CSF) outbreaks in The Netherlands, Haiti, and the Dominican Republic, Foot-and Mouth Disease (FMD) in Taiwan, the Nipah virus outbreak in Malaysia, and FMD in the U.K. and Europe have heightened interest by producers and practitioners in what the U.S. is doing to prevent the incursion of a FAD. Many would view the risk of entry of a FAD or an emerging disease as increasing.


Risks to U.S. Swine Herds


The increased risk is attributed to several factors. There are many international visitors to the U.S. that may have contact with U.S. herds and recently been on farms in their own country. Tour groups of producers from other countries to view U.S. animal agriculture are extremely common. In addition, many U.S. producers travel internationally to view production practices in other countries. Veterinarians, animal scientists, and animal agriculture students are frequently consulting with or conducting research in other countries and then returning to work with U.S. herds. With “free trade” agreements, there is the potential for an increase in the flow of various products from a larger number of countries. This increase in diversity may contribute to increased risk. A major concern is the illegal importation of products that may carry infectious diseases. Border controls are critical to intercept this type of contraband. Animals may also be illegally imported and therefore, not be subjected to U.S. import testing requirements. Recently, there has been a heightened awareness of the potential for bioterrorism to be directed to animal populations.


Key Diseases of Concern to the U.S. Pork Industry


The three main diseases of concern to the U.S. pork industry are Foot-and-Mouth Disease (FMD) and other vesicular diseases, Classical Swine Fever (Hog Cholera) and African Swine Fever.


FMD is a highly contagious viral disease that affects cloven-hoofed animals such as cattle, swine, sheep, goats and deer. Signs of the disease include fever and blister-like lesions on the tongue and lips, in the mouth, on the teats and between the hooves. Animals can recover from the disease, but FMD causes severe losses in meat and milk production and leaves the animal debilitated. Due to the contagious nature of the disease and its drastic consequences, infected herds are normally destroyed. Humans can potentially serve as carriers if the virus contaminates clothes, footwear and the body, particularly the throat and nasal passages.


Foot-and-Mouth Disease can be confused with other vesicular diseases, Vesicular Stomatitis, Swine Vesicular Disease, and Vesicular Exanthema. Whenever mouth or feet blisters or other typical signs are seen, laboratory tests must be completed to determine whether the disease causing them is FMD. Animals, people, or materials such as contaminated clothing, footwear, equipment, vehicles, hay, or meat products can spread the FMD virus. The virus can persist in contaminated products for significant times depending on the temperature and pH conditions. There are seven separate types and more than 60 subtypes of the FMD virus. Immunity to one type does not protect against other types.


The control strategies for FMD include stamping out (depopulation), pre-emptive slaughter, ring vaccination with later depopulation, and routine vaccination. There are many reasons why FMD vaccine is not used routinely or in outbreaks. They include trade restrictions, the need for repeated vaccinations, availability of differential tests, continued costs of vaccinations, ability for vaccinated animals to become infected, and the need to match the type of vaccine with the FMD virus.


Classical Swine Fever (CSF), also known as Hog Cholera, is a highly contagious viral disease of swine. CSF was eradicated from the U.S. in 1978 after a 16-year effort. It is transmitted most commonly by direct contact with infected swine. It also can be transmitted through contact with body secretions or consumption by swine of untreated food wastes containing pork from infected animals. The disease may be either acute or chronic or congenital. Clinical signs may vary and include high temperatures, piling, conjunctivitis, purplish discoloration of the skin, alternating constipation and diarrhea, a staggering gait, and reproductive problems.


CSF may be confused with several other swine diseases. These include African Swine Fever, erysipelas, Salmonella septicemia, Porcine Reproductive and Respiratory Syndrome, and Porcine Dermatitis and Nephropathy Syndrome.


African Swine Fever (ASF) is a tick-borne, contagious viral disease of swine. It can have either an acute or chronic form. Clinical signs include fever, reddened skin, diarrhea, and abortion. ASF can be confused with CSF and similar diseases.


Role of Government


Many animal diseases have been eradicated from the U.S. through government programs. Until recently, industry also viewed foreign animal disease (FAD) prevention and response as solely a government responsibility. U.S. government efforts to prevent the entry of a FAD focus on people movement, importation of live animals, and importation of animal products. Within the U.S. Department of Agriculture (USDA), there are numerous agencies that have important responsibilities in emergency management. Veterinary Services (VS) is the animal health arm of the Animal and Plant Health Inspection Service (APHIS), USDA. VS personnel in the field, headquarters, or laboratories work to prevent entry of pests and pathogens, to diagnose and control outbreaks, evaluate risks of FADs, provide FAD training and information, monitor for diseases, and respond to potential FAD emergencies.


If a FAD were diagnosed in the U.S., one of the two Regional Emergency Animal Disease Eradication Organizations (READEO) would be activated. READEO team members are trained to confirm the presence of the disease, conduct epidemiological studies, appraise the value of animals that may have to be destroyed, dispose of infected and exposed animals, clean and disinfect premises, set and enforce regulations against disease spread, and conduct vaccination programs.


While VS has a prominent role in emergency management, other USDA agencies provide valuable services. APHIS, Plant Protection and Quarantine (PPQ) inspectors are responsible for inspections at U.S. ports of entry. One of the aids in this detection is the PPQ Beagle Brigade, dogs especially trained to sniff passengers and luggage and detect meat products. In addition, disposal of foreign garbage at ports and airports is closely supervised. APHIS, International Services (IS) maintains officers in foreign countries to facilitate trade and provide assistance and information on FAD outbreaks in other countries.


The USDA’s Agricultural Research Service (ARS) conducts research on foreign animal diseases primarily at its Plum Island, New York facility. Currently, the two major research programs at Plum Island are African Swine Fever and FMD. ARS scientists participate with APHIS in FAD training programs and development of FAD diagnostic tests.


Checkoff Funded Foreign Animal Disease and Biosecurity Activities


Pork producer activities have focused on educational initiatives for producers and veterinarians, research, and national coordination. Checkoff funds have been used to develop a variety of resources to help producers keep their herds safe. A key emphasis has been on biosecurity information for producers. Educational initiatives include:

  • PORK QUALITY ASSURANCE Program – New section on biosecurity including prevention of foreign animal diseases
  • World Pork Expo Directory Information – Section on foreign animal disease and on-farm biosecurity
  • Pork Report Article – “Step Up Your Biosecurity Measures” Sent to 110,000 producers and stakeholders
  • Radio Interviews with Farm Broadcasters and News Hotline Tape
  • Presentations on Biosecurity and Foreign Animal Disease Prevention
  • Foreign Animal Disease Awareness Video – Educates producers about the threat of foreign animal diseases and what producers need to do to protect their farms
  • Foreign Animal Disease and Biosecurity Sections on Web Site –
  • Mailings to American Association of Swine Veterinarians (AASV) – Information on foreign animal diseases sent to all AASV members


Biosecurity information has focused on preventing entry of both domestic and foreign animal diseases. Specific precautions related to foreign animal disease prevention include:

  • Limit Visitors – Use a Sign-in Log
  • Require International Visitors to Observe Pig “Free” Times Based on Diseases Present in Country Are From or Have Visited – USDA Recommends Five Days for FMD Countries
  • Require International Visitors or Employees Who Have Traveled Internationally to Shower and Wear Farm-Supplied Clothing
  • Prohibit International Visitors or Employees From Bringing Imported Food Onto Pork Production Site
  • Prohibit Bringing Any Clothing or Equipment Used at International Pork Production Sites


With regard to research, checkoff funds have been invested in research projects on FMD at the USDA Agricultural Research Service’s Plum Island Animal Disease Center. This research has focused on development of vaccines and improved diagnostic tools. In addition, detailed pork producer biosecurity research priorities have been presented to USDA. The National Pork Board also participated in a review of the FAD research programs at Plum Island. A literature review has been conducted by Dr. Sandy Amass at Purdue University to summarize the current state of knowledge with regard to biosecurity precautions needed for disease prevention.


At the national level, the pork industry has worked with other commodity groups, State and Federal animal health officials and veterinarians to ensure implementation of critical prevention and response capabilities. The industry has been involved in several activities working to prevent an outbreak, including representation on the Secretary of Agriculture’s Advisory Committee on Foreign Animal and Poultry Diseases, participation in the Animal Health Safeguarding Review, and participation in foreign animal disease test exercises for Classical Swine Fever and FMD at the state and national level. The most recent FMD exercise in November 2000 tested the response capabilities of the U.S., Canada and Mexico. During the exercise, the National Pork Board’s Swine Health Committee offered input and producer views on various control and eradication strategies and on how best to communicate with producers during an outbreak.


Since 1996, pork producers have been very active participants in the National Animal Health Emergency Management System (NAHEMS) Steering Committee’s programs to develop a unified Federal and State government and industry approach to preventing and responding to foreign animal diseases. The NAHEMS Steering Committee is composed of animal agriculture industry associations, State veterinarians, veterinary practitioners, and USDA. Recently, the Federal Emergency Management Agency and the National Emergency Management Association have joined the Steering Committee. The Steering Committee believes that a sense of shared responsibility between the animal industry, practitioners, and State and Federal government animal health officials should replace the attitude of emergency management being solely a Federal responsibility. The Steering Committee has been very active in the last four years. Conference calls are held monthly. Two-day meetings take place quarterly. Topical subcommittees carry out specific projects as needed. Key accomplishments include the development of the model for shared emergency management responsibilities, drafting a strategic plan for the U.S. National Animal Health Emergency Management System (NAHEMS), and development of Standards for State Animal Health Emergency Management Systems. Currently, pork producers are taking the lead in developing standards for animal agriculture industry to meet to participate in emergency management activities.


Pork Producer Response to Recent FMD Outbreak in Europe


The National Pork Board was very actively working to ensure that all precautions were taken to ensure that the U.S. remain free of FMD during the recent outbreak in Europe. The National Pork Board’s Swine Health Committee communicated its concerns to USDA and several meetings were held with USDA’s Veterinary Services and Plant Protection and Quarantine and U.S. Customs Service. Information on FMD was sent to swine veterinarians to increase their awareness of the disease and their reporting responsibilities. The pork industry reviewed its communication and response plans. The importance and need for state plans was discussed with state producer associations.




Pork producers have a role in preventing and responding to a foreign animal disease. It is important that each producer institute appropriate biosecurity measures in their operations and that their producer organization is actively engaged with other industry groups, veterinarians, and State and Federal animal health officials in addressing foreign animal disease threats.