Salmonellosis in Pigs: Intestinal Salmonella Infection and Diarrhea
- Salmonellosis is a bacterial intestinal infection that often affects pigs from weaning to about 5 months of age, though pigs of any age can get sick.
- Common signs include fever, reduced appetite, watery yellow diarrhea, dehydration, and a pig that seems weak or less interested in food.
- See your vet promptly if your pig has diarrhea plus fever, blood, weakness, repeated episodes, or signs of dehydration.
- Diagnosis usually needs fecal or tissue testing, because other pig diseases can look very similar.
- Salmonella can spread to people and other animals, so careful handwashing, isolation, and manure hygiene matter.
What Is Salmonellosis in Pigs?
Salmonellosis is an infection caused by Salmonella bacteria. In pigs, it often affects the intestines and can lead to fever, poor appetite, and diarrhea. Some pigs have mild disease, while others become much sicker and may need urgent supportive care.
Intestinal salmonellosis is most often linked to Salmonella Typhimurium, Salmonella Choleraesuis, and the serotype Salmonella enterica 4,[5],12:i:-. Merck notes that pigs from weaning to about 5 months of age are most commonly affected, but disease can occur at other ages too.
One challenge is that some pigs can carry Salmonella without looking sick. These carrier pigs may still shed bacteria in manure and spread infection to pen mates, the environment, and people handling them. That makes early veterinary guidance, isolation, and sanitation especially important for both herd health and household safety in pet pigs.
Symptoms of Salmonellosis in Pigs
- Watery or liquid yellow diarrhea
- Fever
- Reduced appetite or not finishing meals
- Lethargy or weakness
- Dehydration, including tacky gums or sunken eyes
- Feces with mucus, necrotic shreds, or occasionally blood
- Weight loss or poor growth if illness is prolonged
- Recurring bouts of diarrhea over several days
Many pigs with intestinal salmonellosis have fever plus diarrhea, not diarrhea alone. Merck describes diarrhea that can last 3 to 7 days in an individual pig and may come back in repeated bouts. Some pigs also pass stool with mucus or tissue debris.
See your vet urgently if your pig is weak, not drinking, has bloody stool, seems painful, or is getting dehydrated. Young pigs can decline quickly. Because diarrhea in pigs can also be caused by other infectious diseases, your vet may recommend testing rather than treating based on signs alone.
What Causes Salmonellosis in Pigs?
Pigs usually become infected by swallowing Salmonella from contaminated manure, feed, water, housing surfaces, or equipment. Merck also notes that asymptomatic carrier pigs are a major source of infection. Rodents and contaminated premises can help keep the bacteria circulating.
Stress often plays a role in when disease shows up. Weaning, transport, crowding, mixing pigs, poor sanitation, and other illness can all increase the chance that a pig exposed to Salmonella will become clinically sick.
Not every pig exposed to Salmonella develops severe disease. Some have mild diarrhea, some become carriers, and some develop more serious intestinal inflammation. The exact outcome depends on the strain involved, the pig's age and immune status, the infectious dose, and overall management conditions.
How Is Salmonellosis in Pigs Diagnosed?
Your vet usually starts with a physical exam, temperature check, hydration assessment, and a review of age group, housing, recent stressors, and how many pigs are affected. That history matters because salmonellosis can overlap with other causes of pig diarrhea, including swine dysentery, proliferative enteropathy, coccidiosis, and dietary problems.
A diagnosis is typically confirmed with culture and serotyping of feces or tissue. Merck specifically recommends culture for confirmation, and histologic examination of affected intestine and liver can be very helpful when trying to separate salmonellosis from look-alike diseases.
In practical terms, your vet may suggest a fecal sample, rectal swab, or testing through a veterinary diagnostic lab. Depending on the case, they may also recommend necropsy of a deceased pig from the group, because that can provide the clearest answer during an outbreak. A one-time positive fecal result may not tell the whole story in a pig without signs, so your vet will interpret test results alongside symptoms and herd context.
Treatment Options for Salmonellosis in Pigs
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Office or farm-call exam with hydration and temperature assessment
- Isolation of the sick pig and manure-control guidance
- Supportive care plan from your vet, often focused on fluids, warmth, easy access to water, and monitoring
- Targeted fecal testing when feasible, or initial stabilization before more diagnostics
- Discussion of whether antimicrobials are appropriate based on severity and herd risk
Recommended Standard Treatment
- Veterinary exam plus fecal or tissue culture through a diagnostic lab
- Fluid therapy plan, often oral or injectable depending on hydration status
- Antimicrobial selection guided by your vet, ideally with culture or susceptibility information when possible
- Group-management recommendations for exposed pigs, sanitation, and rodent control
- Recheck exam or follow-up testing if diarrhea persists or recurs
Advanced / Critical Care
- Hospitalization or intensive on-farm care for severe dehydration, weakness, or systemic illness
- IV fluids or more aggressive fluid support
- CBC, chemistry, and additional diagnostics as available
- Necropsy and herd-level outbreak workup when multiple pigs are affected
- Expanded biosecurity planning, environmental decontamination strategy, and close veterinary follow-up
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Salmonellosis in Pigs
Bring these questions to your vet appointment to get the most out of your visit.
- Does my pig's diarrhea pattern fit salmonellosis, or are other causes more likely?
- What tests would give us the most useful answer right now: fecal culture, PCR, bloodwork, or necropsy?
- Is my pig dehydrated, and what signs should I monitor at home today?
- Does my pig need antimicrobial treatment, or is supportive care the better first step in this case?
- How should I isolate my pig and clean the enclosure to reduce spread?
- Are other pigs in contact at risk, and should any of them be monitored or tested?
- What zoonotic precautions should my household take, especially around children, older adults, or anyone immunocompromised?
- What would make you want to recheck my pig or escalate care right away?
How to Prevent Salmonellosis in Pigs
Prevention focuses on biosecurity, sanitation, and stress reduction. Clean manure promptly, keep feed and water sources from becoming contaminated, control rodents, and avoid mixing pigs from different sources without a plan from your vet. Good ventilation, lower stocking density, and careful weaning management can also help reduce disease pressure.
If one pig develops diarrhea, separate that pig as soon as possible and handle healthy pigs first. Wash hands well after contact, clean boots and tools, and avoid tracking manure between pens. This matters because Salmonella is zoonotic, meaning it can infect people.
Merck notes that live avirulent vaccines may help prevent disease caused by some important pig Salmonella strains and may reduce tissue contamination at slaughter. Vaccination is not the right fit for every pig or every setting, so it is best discussed with your vet as part of a broader prevention plan rather than used as a stand-alone fix.