Feral Swine Disease Risks to Domestic Swine

Feral Swine Disease Risks to Domestic Swine
Why should I worry about feral swine?
Feral swine and domestic swine are both the same species (Sus scrofa) meaning they
can be infected with the same diseases. Pasture-raised pigs, non-confined domestic
swine, and other outdoor swine practices can increase the risk of feral swine transmitting
pathogens and parasites. Since feral swine roam freely, they can also contaminate
accessible feed and water sources meant for domestic pigs.

Disease impacts to domestic swine production
Swine are social animals; domestic swine may interact with feral swine in pastures or through fences.
Feral boar will even breed with domestic sows if they can access them. These interactions can result
in transmission of pathogens not usually found in domestic swine. Infections can result in reduced
productivity, abortions, reduced number of piglets, or even death. Pasture-raised pigs are also
susceptible to acquiring parasites from feral swine, which can result in consumer health concerns
and market losses.

Diseases of concern for domestic swine production
Disease

Routes of Transmission

Symptoms

Brucellosis (Brucella
species bacteria)

Direct contact with aborted fetuses, afterbirth, or
vaginal discharges. Ingestion of contaminated feed,
water, or tissues.

Infertility, abortion, vaginal discharge,
lameness, and swollen testicles.

Pseudorabies (Aujeszky’s
disease or “mad itch”)

Nose-to-nose or sexual contact. Ingestion of
contaminated water, feed, or infected tissues.
Through contaminated equipment or clothing or by
airborne virus.

Abortions, infertility, fever, sneezing,
coughing, pneumonia, incoordination;
stillbirth, abortion, piglet mortality.

Porcine Reproductive
and Respiratory
Syndrome

Direct contact with nasal discharge, feces, urine,
saliva or through sexual contact. Contaminated
feed, water, or equipment or by airborne virus.

Lack of appetite, lethargy, coughing,
pneumonia, skin discoloration, stillbirth,
weak piglets, and reduced milk production.

Porcine Circovirus
Type 2

Direct contact with infected animals, through nasal
discharge, feces, urine, or saliva.

Weight loss, jaundice, diarrhea, respiratory
distress, and swollen lymph nodes.

Giant Kidney Worm

Ingestion of larvae, penetration through the skin, or
through infected earthworms.

Loss of appetite, weight loss, blood in urine.

Porcine Epidemic
Diarrhea Virus

Contact with infected feces directly or through
contaminated, feed, water, soil, or surfaces.

Acute watery diarrhea and vomiting.

Trichinellosis

Ingestion of muscle tissue infected with the
encysted larval stage of the parasite.

Vomiting and diarrhea, larvae may migrate
and form cysts in muscle tissue.

Toxoplasmosis

Ingestion of tissue cysts in undercooked or raw
meat, or of food and water contaminated with
oocysts. Also, the consumption of rodents.

Clinical signs are uncommon in adults but
may cause an increase in stillbirths or
premature, weak piglets. Diarrhea may occur.

Salmonellosis

Ingestion of contaminated feces, food or water.

Fever, lethargy, lack of appetite, and rancid,
watery or bloody diarrhea.

Animal and Plant Health Inspection Service

Feral Swine Disease Risks to Domestic Swine
What is at risk?
The United States is the second largest producer of pork in the world,
generating $34 billion of revenue in the United States per year. An increasing
amount of pork producers in the United States, nearly 37%, are located in
regions where feral swine are common. Disease introductions from feral swine
could have a huge financial impact on your farm through losses in
productivity and trade. It is important to protect your livestock by reducing
any potential for exposure to feral swine.

How can I protect my domestic swine from becoming infected?
• Take additional precautions to prevent interactions with your pigs if feral swine are found in your area.
See the map to determine where feral swine currently exist.

• Store feed in barns or prevent feral
swine from accessing feed.

•

Avoid feeding in troughs or on the
ground which can increase the risk
of pathogen transmission since feral
swine can easily access the feed.

• Prevent feral swine access to water
sources used by domestic swine.

• Prevent direct contact between

feral swine and domestic swine by
maintaining fences and keeping
pigs confined, especially at night.

Want to learn more?
Call Wildlife Services, a program within the U.S. Department of Agriculture's
(USDA) Animal and Plant Health Inspection Service, at 1-866-4-USDA-WS or visit
www.aphis.usda.gov/wildlife-damage/stopferalswine to learn more about
the problems caused by this invasive animal, as well as to seek advice and
assistance in dealing with feral swine.