Brucellosis in Pigs: Brucella suis Infection, Reproductive Signs, and Safety
- See your vet immediately if a pig has abortion, infertility, swollen testicles, lameness, or exposure to feral swine.
- Brucellosis in pigs is caused by *Brucella suis*, a bacterial infection that can spread to people through tissues, fluids, and carcass handling.
- Reproductive problems are common, including smaller litters, stillbirths, weak piglets, temporary or permanent sterility, and boar infertility.
- There is no practical curative treatment or vaccine for swine brucellosis. Management usually focuses on testing, isolation, herd control, and public health reporting.
- Typical veterinary cost range for exam, sample collection, and laboratory screening is about $150-$500 per pig, with herd investigation and regulatory testing often adding substantial costs.
What Is Brucellosis in Pigs?
Brucellosis in pigs is a contagious bacterial disease caused by Brucella suis. It mainly affects the reproductive tract, but it can also involve joints, bones, and other tissues. In pigs, the disease is best known for causing abortion, infertility, stillbirths, weak piglets, orchitis, and lameness.
This is also a zoonotic disease, which means people can get infected. Human exposure can happen during farrowing, handling aborted tissues, processing carcasses, butchering feral swine, or contacting contaminated fluids. That makes brucellosis more than a herd health issue. It is also a family, farm, and workplace safety issue.
In the United States, infection in commercial domestic swine is now rare, but feral swine remain an important reservoir. Pigs with outdoor access or contact with wild or feral pigs have higher risk. Because the disease can persist in a herd and has reporting implications, early veterinary involvement matters.
Symptoms of Brucellosis in Pigs
- Abortion, especially after breeding or during pregnancy
- Smaller litters, stillbirths, or weak piglets
- Temporary or permanent infertility
- Swollen testicles, orchitis, or swollen accessory sex glands in boars
- Lameness or reluctance to move
- General poor breeding performance in a herd
Brucellosis can be hard to spot early because some pigs look normal until breeding problems appear. In many cases, the first signs are reproductive: abortion, infertility, smaller litters, stillbirths, or weak newborn piglets. Boars may develop swollen testicles or reduced fertility, and some pigs show lameness instead of obvious reproductive signs.
When to worry: see your vet immediately if a pig aborts, a boar develops testicular swelling, several pigs show fertility problems, or your pigs may have had contact with feral swine. Because this disease can spread to people, wear gloves when handling birthing fluids, placentas, aborted material, or carcasses, and keep children and immunocompromised family members away until your vet advises next steps.
What Causes Brucellosis in Pigs?
Brucellosis in pigs is caused by infection with Brucella suis. The bacteria spread mainly through contact with infected tissues and fluids. That includes placentas, aborted fetuses, vaginal discharge, semen, blood, and contaminated environments. Infected boars can spread the organism during breeding, and pigs may also become infected by eating contaminated tissues.
In the United States, feral swine are the main source of infection risk for domestic pigs. Outdoor pigs, backyard pigs, hunting dogs that move between feral swine and home settings, and farms with weak perimeter fencing may all face higher exposure risk. Bringing in replacement pigs from unknown health backgrounds also raises risk.
Once infected, pigs can carry the bacteria for long periods and may shed it for years. That is one reason herd control is challenging. A single sick pig may represent a larger herd problem, so your vet may recommend testing herd mates and reviewing biosecurity at the same time.
How Is Brucellosis in Pigs Diagnosed?
Diagnosis usually starts with history and risk assessment. Your vet will ask about abortions, infertility, boar fertility, lameness, recent pig purchases, outdoor housing, and any possible contact with feral swine. Because several pig diseases can cause reproductive loss, brucellosis cannot be confirmed by signs alone.
The main screening tools are serologic blood tests, such as the brucellosis card test and other agglutination or complement fixation tests. In some cases, confirmatory testing may include culture, PCR, or testing of tissues from aborted fetuses, placenta, lymph nodes, or reproductive organs through a veterinary diagnostic laboratory.
This disease has regulatory and public health importance. If your vet suspects brucellosis, they may need to involve the state animal health official or USDA APHIS, depending on the situation and local rules. That can feel stressful, but it helps protect your pigs, nearby herds, and the people handling them.
Treatment Options for Brucellosis in Pigs
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Urgent veterinary exam and risk review
- Isolation of affected pigs from the rest of the herd
- Basic blood testing on the affected pig or highest-risk animals
- Strict glove use and limited handling of reproductive tissues
- Immediate stop to breeding until your vet advises next steps
- Fence and contact review to reduce exposure to feral swine
Recommended Standard Treatment
- Veterinary exam plus herd-level history and exposure mapping
- Serologic testing of affected and exposed pigs
- Diagnostic lab submission of tissues when available
- Isolation or removal of positive or suspect animals as directed by your vet and animal health officials
- Breeding pause and biosecurity plan
- Cleaning and disinfection of contaminated farrowing or breeding areas
- Coordination with state or federal animal health authorities when required
Advanced / Critical Care
- Full herd investigation with serial testing plans
- Regulatory case management and trace-back or trace-forward review
- Removal or depopulation planning when advised by animal health officials
- Advanced perimeter biosecurity, double fencing, and feral swine exclusion upgrades
- Necropsy and expanded laboratory workup to rule out other reproductive diseases
- Occupational safety planning for family members, staff, and handlers
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Brucellosis in Pigs
Bring these questions to your vet appointment to get the most out of your visit.
- Based on my pig's signs and history, how likely is brucellosis compared with other causes of reproductive loss?
- Which pigs should be tested first, and what blood or tissue tests do you recommend?
- Do I need to isolate this pig right now, and how should I handle bedding, placentas, or aborted material safely?
- Could exposure to feral swine be part of the risk on my property?
- Are there any reporting requirements in my state if brucellosis is suspected or confirmed?
- What should family members, farm workers, or anyone handling this pig do to reduce human exposure risk?
- Should breeding stop for the whole herd until test results are back?
- What biosecurity changes would most reduce the chance of this happening again?
How to Prevent Brucellosis in Pigs
Prevention is the most important strategy because there is no vaccine and no practical curative treatment for swine brucellosis. The biggest steps are keeping domestic pigs away from feral swine, buying pigs from known low-risk sources, and using strong biosecurity around breeding animals. Double fencing, secure feed storage, and avoiding nose-to-nose contact with wild pigs can make a real difference.
If you add pigs to your group, talk with your vet about testing and quarantine before mixing them with the herd. Breeding boars should come from herds with strong health records, and any pig with reproductive problems should be evaluated before further breeding. Good records on breeding dates, litter size, abortions, and boar fertility help your vet spot patterns early.
Human safety matters too. Wear gloves when helping with farrowing, handling placentas, cleaning up abortions, butchering feral swine, or touching carcasses. Wash hands well, protect cuts, and avoid splashes to the eyes or mouth. If anyone in the household develops fever, sweats, fatigue, joint pain, or feels ill after pig or carcass exposure, they should contact a physician promptly and mention possible Brucella suis exposure.
For meat safety, avoid feeding raw feral swine tissues to pigs or dogs, and cook wild hog meat thoroughly. USDA APHIS advises gloves during carcass handling, and APHIS notes cooking feral swine meat to at least 160°F for safety. Freezing, smoking, drying, or pickling does not reliably kill Brucella.