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International Travel: A Disease Risk for Livestock

Samantha ShieldsFarm Visitors, Livestock diseases Leave a Comment

During October 2019, Australia’s agriculture minister cancelled a Vietnamese woman’s visa after authorities found 22 pounds of undeclared food products in her luggage. The luggage contained pork, quail, squid, pâté, fruit, eggs and garlic (Griffiths, 2019). International travel and trade increases the risks of introducing a foreign/exotic disease or pest into another country. Australia had to develop an extensive eradication program in 2010, after the fungal disease chestnut blight was brought into the country and then detected on native trees.

Native Ecosystems, Agriculture Impacted by Disease Introductions

Often, native ecosystems do not have the ability to resist these foreign threats. Exotic diseases and pests are also significant threats to global agricultural production. African swine fever (ASF) is a foreign animal disease of pigs that has forced countries to increase their border security, in response to several rapid and deadly outbreaks.

International Outbreaks of African Swine Fever

Historically, ASF outbreaks have been reported in Africa and parts of Europe, South America and the Caribbean. Since 2007, the disease has been reported in multiple countries across Africa, Asia and Europe, in both domestic and wild pigs (World Organisation for Animal Health (OIE)). Concerns about ASF being introduced to the United States have greatly increased since recent international outbreaks during 2018 (Feedstuffs, 2019). As of December 2019, the United States has not been affected by ASF.

If African swine fever should enter the United States, it has the potential to severely impact livestock producers, consumers and the economy. There could be a pork and pork by-product shortage, an increase in pork prices, and a tremendous loss of income for pork producers. ASF might already be reaching United States borders; all ports of entry are possible inlets for its introduction. Five U.S. airports account for 90 percent of the potential risk (Jurado C., et al., 2019):

  • Newark Airport (New Jersey).
  • George Bush-Houston Airport (Texas).
  • John F Kennedy Airport (New York).
  • San Jose (California).
  • Los Angeles (California).

USDA and CBP Response

Thanks to the United States Department of Agriculture (USDA) and United States Customs and Border Protection (CBP), ASF has not entered the U.S. and caused an outbreak yet. International travelers entering or re-entering the United States must fill out a form to declare who they are, and what they are bringing into the U.S. with them. The declaration form is used as a means to prevent the entry of dangerous agricultural pests and prohibited wildlife, by screening for restricted items such as:

  • Fruits.
  • Vegetables.
  • Plants.
  • Plant products.
  • Soil.
  • Meat.
  • Meat products.
  • Birds.
  • Snails.
  • Other live animals or products.

Any of these restricted items can harbor harmful diseases, such as ASF on pork products. The USDA and CBP also use specially trained dog teams for secondary inspections, to investigate incoming luggage for restricted agricultural and wildlife products. In response to ASF, 60 more beagle teams will be added in the coming year.

Biosecurity Measures for Farm Visitors

The USDA and CBP are the first lines of defense at the U.S. borders to stop the importation of foreign diseases and pests. Producers can be their own lines of defense in minimizing disease introductions to livestock. All farm visitors are potential carriers of infectious disease agents, but visitors who traveled internationally pose a greater risk of bringing foreign animal diseases with them. Visitors can carry disease agents in their throats, nasal passages, on personal belongings and on food products for several days after leaving a foreign country. Livestock producers should practice the following biosecurity measures to lower the risk of disease introductions from visitors (CFSPH, 2019):

  • Pre-approve visitors before they arrive.
  • Ask visitors if they traveled internationally, and when they returned; visitors should wait at least five days after international travel before visiting a farm.
  • Ask visitors to shower, wash their hair and blow their nose before arrival.
  • Create a separate parking area away from farm facilities.
  • Do not allow visitors to bring food products and personal items with them.
  • Have site-specific protective gear including specific footwear and coveralls available for visitors to wear.
  • Keep an escort with visitors at all times.
  • Prevent visitors from having any direct contact with livestock.

Travelers Can Help Prevent Disease Introductions

International travelers and other visitors can do their part to protect farm livestock as well. (CDFA, 2016). Biosecurity measures visitors and travelers can take include:

  • Avoid wearing any items on a trip that will be worn again on a farm after returning.
  • Use disposable protective gear during farm visits.
  • Declare an international farm visit on the customs form to have items disinfected properly.
  • Declare any items being brought into the U.S.
  • Avoid bringing prohibited items across borders.

The combined efforts of the USDA, CBP, livestock producers and travelers has helped to keep ASF from entering the United States. It is important for travelers to realize that upon return to the U.S., they could be carrying a foreign animal disease or pest with them.

Keeping biosecurity measures in mind when traveling or hosting farm visitors will limit the potential for foreign animal disease introductions like African swine fever.


Griffiths J. (October 2019). Australia expels Vietnamese Tourist Caught with Raw Pork in Her Luggage. Retrieved From: https://www.cnn.com/travel/article/australia-vietnam-pork-customs-intl-hnk-scli/index.html

California Department of Food and Agriculture (CDFA). (August 2016). International Travel Biosecurity Tips – Best Practices for Producers [PDF File]. Retrieved from: https://www.cdfa.ca.gov/ahfss/Animal_Health/pdfs/biotipsft.pdf

Swine Health/Pork Checkoff. (2019). Hosting International Visitors on Your Farm. Retrieved from https://www.swinehealth.org/wp-content/uploads/2018/08/TravelBiosecurity_Handout__International_Visitors_November2016_FINAL.pdf

Jurado, C., Mur, L., Pérez Aguirreburualde, M.S. et al. (2019). Risk of African swine fever virus introduction into the United States through smuggling of pork in air passenger luggage. Sci Rep 9, 14423. https://www.nature.com/articles/s41598-019-50403-w

World Organisation for Animal Health. Key Facts About African Swine Fever. Retrieved from https://www.oie.int/en/animal-health-in-the-world/animal-diseases/african-swine-fever/

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About the Author

Samantha Shields

Samantha Shields was an undergraduate student at the University of Vermont, studying for a Bachelor of Science in Biological Science, and a minor in Animal Science. She worked with ADBCAP Director Julie M. Smith, DVM, PhD, as an online outreach assistant intern. Samantha assisted with content development for the Healthy Farms Healthy Agriculture website by evaluating, summarizing, and presenting information about protecting animal health. At the University of Vermont, she was an active member of many programs including RALLYTHON, University of Vermont Program Board, Campus Recreation, and the Women’s Club Hockey. Samantha is interested in pursuing the field of epidemiology after graduation. She has a particular interest in the research of different factors that result in diseases, as well as public health emergency planning and response.

About the Editor

Joanna Cummings

Joanna Cummings received a Bachelor of Science in Horticulture from The Pennsylvania State University (PSU), with a specialization in vegetable crop and greenhouse production. At PSU, she was a research technician on no-tillage vegetable crop experiments, and a greenhouse assistant in the All-American Selections Research Gardens. Her career in the agriculture industry includes field research, work with dairy and vegetable farms, and as a greenhouse manager, estate gardener, landscaping and market garden entrepreneur. She transitioned to the science communication field after receiving a master of science degree in environmental communications from Antioch University New England. At Antioch, Joanna was a field botany laboratory teaching assistant, manager of the herbarium, and editor of the department's student newsletter, Notes and Niches. She currently works with Research Professor Julie M. Smith as a communications professional in the University of Vermont Animal and Veterinary Sciences Department. She is the webmaster for the Healthy Farms Healthy Agriculture website.

About the Editor

Dr. Julie Smith

Dr. Julie Smith is a research professor at the University of Vermont. Julie received her B.S. in biological sciences, D.V.M., and Ph.D. in animal nutrition at Cornell University. Since 2002, she has applied her veterinary background to programs in the areas of herd health, calf and heifer management, and agricultural emergency management. She has taught courses in animal welfare, calf biology and management, and ABCs of biosecurity to undergraduates, mostly in the Department of Animal and Veterinary Sciences. As a veterinarian and spouse of a dairy farmer, Julie is well aware of the animal health and well-being concerns of dairy animals. Julie has conducted trainings for Extension educators, livestock producers, and community members on the risks posed by a range of animal diseases, whether they already exist in the United States, exist outside of the United States, or pose a risk to both animal and human health. In all cases, she emphasizes the importance of awareness and prevention. In addition, she has led a number of projects on biosecurity and emergency disease preparedness.


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