Agriculture Information Bulletin No. 799

United States Department of Agriculture

Animal and Plant Health Inspection Service

Feral/Wild Pigs:

Potential Problems for 

Farmers and Hunters

at risk when they field-dress and butcher wild pigs 

and should take the following precautions:

1. Always wear disposable plastic or rubber gloves 

when field-dressing, cleaning, and butchering a 

wild pig carcass. Avoid direct contact with blood 

and reproductive organs.

2. As soon as possible, wash hands with soap and 

hot water after dressing wild pigs.

3. Burn or bury gloves and remains from butchered 

wild pigs.

4. Cook wild pig meat thoroughly.

 The symptoms of swine brucellosis in humans 

are not distinctive enough for a clear-cut diagnosis. 

Most people report recurring fever, chills, sweating, 

weakness, headaches, pains in muscles or joints, 

loss of appetite, and weight loss. People with 

these symptoms who have been exposed to wild 

pigs should consult their doctor about swine 

brucellosis.

Pseudorabies

Another important disease harbored by wild pigs 

is pseudorabies. Despite its name, this disease, 

caused by a herpesvirus, is not related to rabies 

and does not affect people. However, pseudorabies 

is of great economic importance to the domestic 

swine industry. It weakens pigs, leaving them 

susceptible to other problems, and causes 

abortions and stillbirths.

 A cooperative State, Federal, and industry 

program managed by the USDA’s Animal and Plant 

Health Inspection Service (APHIS) has eradicated 

pseudorabies from commercial-production swine 

herds in the United States. Because commercialproduction swine are now free of pseudorabies, 

reinfection via feral pig exposure would be 

economically devastating to the pork industry.

 Adult swine can be silent carriers of 

pseudorabies and will periodically shed the virus 

through the nose and mouth. Once infected, the 

pig is a lifetime carrier, and there is no effective 

treatment. Pseudorabies can be detected by blood 

testing, and evidence of pseudorabies infection in 

wild pigs has been found in at least 11 States.

 Pseudorabies is a fatal disease in other farm 

animals, such as cattle, sheep, and goats, and in 

dogs and cats. Wild mammals, such as raccoons, 

The U.S. Department of Agriculture (USDA) prohibits 

discrimination in all its programs and activities on the basis 

of race, color, national origin, age, disability, and where 

applicable, sex, marital status, familial status, parental 

status, religion, sexual orientation, genetic information, 

political beliefs, reprisal, or because all or part of an 

individual’s income is derived from any public assistance 

program. (Not all prohibited bases apply to all programs.) 

Persons with disabilities who require alternative means for 

communication of program information (Braille, large print, 

audiotape, etc.) should contact USDA’s TARGET Center at 

(202) 720–2600 (voice and TDD). To file a complaint of 

discrimination, write to USDA, Director, Office of Civil Rights, 

1400 Independence Avenue, S.W., Washington, D.C. 20250–

9410, or call (800) 795–3272 (voice) or (202) 720–6382 

(TDD). USDA is an equal opportunity provider and employer.

This publication supersedes “Wild Pigs: Hidden Danger for 

Farmers and Hunters” (Agriculture Information Bulletin No. 

630), published in 1991 and revised in 1999.

Photo credits: All images in this brochure come from the 

APHIS photo library.

Additional copies of this brochure are available at no 

charge from:

Publications Distribution

USDA, Animal and Plant Health Inspection Service

Unit 1

4700 River Road

Riverdale, MD 20737–1229

Issued October 2005

skunks, foxes, opossums, and small rodents, 

also can be fatally infected. The virus attacks 

the nervous system in these animals and can 

produce intense itching followed by paralysis and 

death. Although people are not directly at risk, 

hunters need to know that their dogs could become 

fatally infected through exposure to wild pigs with 

pseudorabies.

 To minimize the threat wild pigs pose to 

domestic swine operations, farmers should take 

the following precautions:

1. Do not introduce wild pigs into herds or attempt 

to market pigs caught in the wild.

2. Before transporting breeding swine, have blood 

tests performed according to State or Federal 

guidelines.

3. Blood-test all new stock before adding them to 

the existing herd.

4. Fence out feral and wild pigs from areas with 

domestic swine.

5. Do not butcher wild pigs on the farm or feed 

offal from field-dressed wild pigs to domestic 

swine.

 Both State and Federal laws govern disease 

control programs for swine brucellosis and 

pseudorabies in all classes and types of swine. 

Relocating wild pigs without negative blood tests 

for these diseases violates the law. Before wild 

pigs are moved, they should be blood-tested by 

a veterinarian to certify that they are free from 

disease.

 Wild pigs are highly adaptable, prolific animals. 

Thus, wild pig control requires a sustained and 

integrated approach, which may include various 

forms of exclusion fencing and cage traps, plus 

ground shooting, trained hunting dogs, and aerial 

hunting. Check State laws and regulations 

concerning feral or wild pig hunting permits, if 

required, for the various control techniques. 

Individuals should contact their State Veterinarian 

or the Wildlife Services unit of APHIS before moving 

wild pigs intrastate or interstate.

 Following the sanitary procedures outlined in this 

brochure is important to prevent human infection 

with swine brucellosis and to make sure that 

this disease, pseudorabies, and other potential 

infections do not make their way into farm livestock 

and companion animals from infected feral pigs. 

The following Web sites are available for additional 

information about wild pigs:

APHIS:

http://www.aphis.usda.gov/programs/programs.

html

Southeastern Cooperative Wildlife Disease Study: 

http://www.uga.edu/scwds

Texas Animal Health Commission:

http://www.tahc.state.tx.us

Noble Foundation:

http://www.noble.org

You may also phone APHIS’ Wildlife Services toll 

free at 1–866–4USDA–WS (1–866–487–3297) for 

assistance in dealing with feral pigs.

Figure 3—

Before you 

move wild 

pigs, get them 

blood-tested by 

a veterinarian 

to be sure 

they are free 

from diseases 

that could be 

transmitted to 

domestic pigs 

or people.

Figure 4—

Cage traps 

are effective 

in trapping 

wild hogs, 

especially 

when food 

supplies are 

limited, as 

in winter.
Important Diseases

Wild pigs are susceptible to several serious swine 

diseases: swine brucellosis, pseudorabies, 

classical swine fever, and African swine fever.

 African swine fever—a major foreign animal 

disease—has never been found in the United 

States. The U.S. Department of Agriculture (USDA) 

eradicated classical swine fever (formerly known as 

hog cholera) from this country in 1976. Although 

swine brucellosis and pseudorabies have been 

eliminated from U.S. commercial-production swine 

herds, hunters and farmers need to be aware that 

wild pigs may be infected with these diseases and 

can readily transmit them to domestic pigs. Moving 

untested wild pigs to new areas or allowing them 

onto farms that have domestic pigs is illegal and 

can have disastrous consequences.

Swine Brucellosis

Swine brucellosis is caused by bacteria very similar 

to the organism that causes brucellosis in cattle, 

and both diseases are a public health concern. 

Swine brucellosis causes abortions in sows and 

infertility in boars. Although this disease does not 

kill pigs outright, it causes losses in reproduction 

that decrease profits for swine producers.

 The swine brucellosis organism is transmitted in 

reproductive discharges, particularly the afterbirth, 

from infected sows or in semen from infected 

boars. Infected swine are disease carriers for life, 

and there is no effective treatment. Detecting 

infected swine through blood tests and culling 

these animals is the only way to remove the 

disease from the herd.

 Swine brucellosis has been reported in wild 

pig populations in at least 14 States based 

primarily on serological prevalence. The disease 

can be spread to domestic swine if wild pigs are 

introduced into local herds. Introduction could be 

intentional, or wild pigs could break into pastures or 

pens to breed with domestic sows.

 Pigs infected with swine brucellosis can serve as 

a source of infection to domestic animals. Cattle 

can also become infected if they come in close 

contact with infected wild pigs.

 Humans can get swine brucellosis through 

handling infected tissues of wild pigs. Hunters are 

ree-ranging populations of wild pigs 

(also called feral swine) exist in at 

least 39 States in this country. Some 

Figure 1—In 1998, feral swine could be found in parts of all the counties shown here in green. By 2004, wild pigs had 

increased their range to counties shown in yellow, while remaining in the green-colored areas as well. Note that wild pigs 

are now found in two counties in Iowa—America’s #1 swine-producing State. (Map adapted from originals created by the 

Southeastern Cooperative Wildlife Disease Study, Athens, GA.)

banks and areas along streams. These 

destructive animals have been known to 

tear through livestock and game fences and 

consume animal feed, minerals, and protein 

supplements.

 Not only do wild pigs feast on field 

crops such as corn, milo, rice, watermelon, 

peanuts, hay, turf and wheat, but they are 

also efficient predators and—when given the 

opportunity—will prey upon young livestock 

and other small animals.

Figure 2—Wild pigs don’t all look alike. Some 

take after the Eurasian wild boar (top left); others 

(bottom left) look almost like domestic pigs. The 

javelina, or collared peccary (above) is native to the 

Southwestern United States.

Wild pigs in the United States are referred to 

by many names, largely because of their mixed 

ancestry. Wild pigs are not native to the United 

States and should not be confused with the 

collared peccary (javelina) of the Southwest. 

Swine were first introduced to the United States 

in 1539, when Spanish explorer Hernando de 

Soto brought them to Florida. After that, it 

was common practice for settlers to allow their 

domestic swine to roam freely. Many years later, 

sport hunters introduced true Eurasian wild boars 

into certain areas of the United States, and their 

bloodlines have become mixed with those of the 

wild pig.

 The feral swine population that exists today is 

a combination of domestic, escaped, or neglected 

domestic swine, Eurasian wild boar, or feral 

pigs that have been captured for the purpose of 

starting wild, free-living populations.

 The intentional movement of trapped feral pigs 

has resulted in extensive crossbreeding of feral 

populations, producing variations in appearance. 

Wild pigs today are often hybrids: some look 

like wild boars, and others look more like the 

common domestic pig in body shape and color. 

It is often difficult to distinguish wild pigs from 

domestic swine based on appearance alone.

experts estimate their numbers at over 4 

million, with the largest populations located 

in California, Florida, Hawaii, and Texas.

 Hunters, farmers, and landowners need to 

be aware of the extensive damage wild pigs 

can cause to their property and livestock. 

The rooting and wallowing activities of 

wild pigs cause serious erosion to river 

F Wild Pig, Russian Boar, Razorback, Piney-Woods Rooter...

Continued