About 20 percent of Vermont dairy farms raise pigs as well as dairy cows. Ninety percent of these farms raise pigs seasonally, and their health concerns may not be a priority for farmers. However, there is growing concern about the global spread of African swine fever (ASF), a deadly foreign animal disease (FAD) of pigs that was identified in two Caribbean countries during 2021.
Since August 2018, ASF has been reported in China, Mongolia, Vietnam, the Philippines, India, Nepal, and other countries. These nations have all taken different actions to prevent its spread, prohibiting the movement of pork products and live pigs. Some nations like China and the Philippines have created regions where pigs and their products cannot leave (ASF situation in Asia & Pacific update, 2023). Despite these measures, in July 2021 ASF reached the Dominican Republic, a Caribbean nation which is on the eastern side of the island of Hispaniola. By September of that year, ASF was confirmed in Haiti which shares the island to the west.
The threat of ASF entering the U.S. has increased because Hispaniola is close to the southern tip of Florida, a distance similar to traveling from New York City to Chicago. As a result, USDA APHIS officials have suspended imports of pork products, byproducts, and semen from Puerto Rico and the U.S. Virgin Islands (USDA APHIS Protect Our Pigs, n.d.). The USDA announced a $500 million investment to prevent ASF from entering the U.S. These funds will be used to monitor, survey, quarantine, or if need be, eradicate the disease (Cima, 2021).
African swine fever can look deceptively like other common pig diseases. A high fever, decrease in appetite and fatigue are the most typical signs. Other common pig diseases with these signs include:
- Porcine reproductive and respiratory syndrome (PRRS).
- Salmonella choleraesuis.
- Erysipelas.
- Porcine dermatitis and nephropathy syndrome (PDNS).
It also looks like classical swine fever, another foreign animal disease. Signs of ASF include red, blotchy skin, diarrhea/vomiting, coughing and difficulty breathing, and sudden death (African Swine Fever (ASF), 2022). The incubation period can be anywhere from four to 19 days. In some of the worst cases, there is sudden death with minimal signs. While not as infectious as some viruses, it is almost always deadly.
ASF signs in pigs. Image source: USDA Protect Our Pigs program.
Although ASF is a serious threat to both domestic and feral pigs, it does not spread to humans or other livestock such as cows. The virus can live in the environment for days to weeks and can be spread by contact with an infected animal’s body fluids either directly or indirectly. Direct transmission, as it sounds, means there is contact between sick and healthy animals, leading to a spread in the virus. Indirect transmission occurs when there is a transfer to animals from objects—also called fomites—such as feed, boots, water troughs, buckets, shovels, tractor tires, etc.
Transmission of diseases to farm animals by indirect contact from boots, farm vehicles or water troughs.
If someone walks into a virus contaminated barn and does not change their shoes before walking into a barn with healthy animals, they can spread the virus. Garbage feeding, where byproducts of pork are fed back to pigs, is another potential means of transmission. In some areas of the world, ASF is spread by certain species of soft-bodied ticks. It is unknown if soft-bodied ticks in the U.S. could be vectors to spreading the disease organisms (CDC, 2015; Beltrán-Alcrudo et al., 2017).
The horrifying truth is that there is no cure for ASF. There is no treatment or commercially available vaccine. Once pigs are infected they are a risk to others, and in many countries infected pigs are culled (African Swine Fever, n.d.).
Farmers who raise pigs in addition to other species of livestock on their farms, even if it is one or two pigs for family consumption, can be proactive:
- Practice biosecurity to prevent disease introductions in farm animals.
- Become familiar with the signs of foreign animal disease infections by learning about “BUDDIES.” These are clinical signs that are unusual or occur at unusual frequency in animals, and may show serious disease or an emerging or foreign animal disease.
- Visit the USDA Protect Our Pigs website for helpful information about ASF and how to prevent it.
References
ASF situation in Asia & Pacific update. (2023, March 16). AnimalHealth. https://www.fao.org/animal-health/situation-updates/asf-in-asia-pacific/en
Beltrán-Alcrudo, D., Arias, M., Gallardo, C., Kramer, S. & Penrith, M. L. (2017). African swine fever: detection and diagnosis – A manual for veterinarians. FAO Animal Production and Health Manual No. 19. Rome. Food and Agriculture Organization of the United Nations (FAO). 88 pages. https://www.fao.org/3/i7228e/i7228e.pdf
CDC. (2015, October 15). Tick-borne relapsing fever distribution. Centers for Disease Control and Prevention. Retrieved Jan. 2023 from https://www.cdc.gov/relapsing-fever/distribution/index.html
Cima, G. (2021, October 13). African swine fever confirmed in Haiti. American Veterinary Medical Association. Retrieved Jan. 2023 from https://www.avma.org/javma-news/2021-11-01/african-swine-fever-confirmed-haiti
Iowa Department of Agriculture & Land Stewardship. (n.d.). African Swine Fever. https://iowaagriculture.gov/animal-industry-bureau/african-swine-fever
Smith, J. & Cummings, J. (n.d.). General Biosecurity. Healthy Farms Healthy Agriculture. Retrieved from https://www.healthyagriculture.org/prevent/biosecurity/
USDA APHIS. (2022, August 31). African Swine Fever (ASF). https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/swine-disease-information/african-swine-fever/seminar
USDA APHIS. (n.d.). Protect Our Pigs. Fight African Swine Fever. https://www.aphis.usda.gov/aphis/resources/pests-diseases/asf
World Organization for Animal Health. (n.d.). African swine fever. WOAH – World Organization for Animal Health. Retrieved Jan. 2023 from https://www.woah.org/en/disease/african-swine-fever/
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