Ileitis in Pigs: Symptoms, Causes, and Treatment
- See your vet immediately if your pig has black, tarry stool, visible blood in the manure, sudden weakness, pale skin, or collapse. Hemorrhagic ileitis can become life-threatening fast.
- Ileitis in pigs is usually caused by *Lawsonia intracellularis*, a bacterium that damages and thickens the intestines, especially the ileum.
- Common signs include sudden diarrhea, poor growth, weight loss, reduced appetite, and a rough hair coat. Some pigs have mild disease, while others develop chronic wasting or sudden bleeding.
- Diagnosis often combines herd history, exam findings, fecal or oral-fluid PCR, and confirmation with intestinal histopathology or immunohistochemistry when needed.
- Treatment options may include fluids, supportive care, and vet-directed antimicrobials for affected pigs and sometimes the group. Vaccination and biosecurity are important for prevention and herd control.
What Is Ileitis in Pigs?
Ileitis in pigs is a common intestinal disease also called porcine proliferative enteropathy. It most often affects growing-finishing pigs and young breeding pigs. The disease is linked to abnormal thickening and inflammation of the intestinal lining, especially in the ileum, but lesions can also involve the jejunum, cecum, and colon.
The usual cause is Lawsonia intracellularis, a small gram-negative bacterium that lives inside intestinal cells. As infected cells keep dividing instead of maturing normally, the gut lining becomes thickened and less effective at absorbing nutrients. That is why some pigs show diarrhea and poor growth, while others lose body condition over time.
Ileitis can look very different from pig to pig. Some cases are mild and self-limiting. Others become chronic with ongoing weight loss, or acute and hemorrhagic with dark, tarry manure, weakness, and sudden death. Because the severe form can progress quickly, any pig with blood in the stool, pallor, or collapse needs urgent veterinary attention.
Symptoms of Ileitis in Pigs
- Loose or watery diarrhea
- Reddish-brown stool or stool lightly tinged with blood
- Black, tarry manure or obvious intestinal bleeding
- Poor growth rate or falling behind pen mates
- Progressive weight loss or poor body condition
- Reduced appetite
- Weakness, lethargy, or reluctance to move
- Pale skin or pallor
- Sudden death in severe hemorrhagic cases
Mild ileitis may look like a short bout of diarrhea with slower weight gain. More serious cases can cause chronic wasting, while hemorrhagic ileitis may cause black or tarry manure, pale skin, weakness, and sudden collapse. See your vet immediately if you notice blood in the stool, marked weakness, rapid weight loss, or any pig that seems suddenly pale or distressed.
What Causes Ileitis in Pigs?
The main cause of ileitis in pigs is infection with Lawsonia intracellularis. This bacterium spreads mainly by the fecal-oral route. Once inside the intestine, it infects cells lining the gut and drives abnormal cell growth, which thickens the intestinal wall and interferes with digestion and absorption.
Not every exposed pig gets equally sick. Disease expression often depends on age, immune status, stocking density, sanitation, stress, feed changes, and other infections present in the herd. Mixed infections are common, so your vet may also consider problems such as salmonellosis or swine dysentery when a pig has diarrhea or blood in the manure.
Ileitis is especially common in growing pigs. Some pigs have subclinical infection with reduced performance rather than dramatic diarrhea. Others develop chronic necrotic enteritis or an acute hemorrhagic form. That range is one reason herd history and testing matter so much.
How Is Ileitis in Pigs Diagnosed?
Diagnosis starts with the pattern of disease in the pig or herd. Your vet will look at age group, manure changes, growth performance, appetite, body condition, and whether there are sudden deaths or signs of intestinal bleeding. Because ileitis overlaps with several other swine intestinal diseases, symptoms alone are not enough for a firm diagnosis.
Testing often includes PCR for Lawsonia intracellularis on feces or oral-fluid samples. PCR can confirm that Lawsonia nucleic acid is present, but a positive result does not always prove it is the only cause of illness because the organism is common in many herds. That is why your vet may pair PCR with other testing to rule out Salmonella, swine dysentery, or additional causes of diarrhea.
For the most definitive diagnosis, your vet may recommend intestinal histopathology, silver stain, or immunohistochemistry on tissue samples, especially in severe, chronic, or fatal cases. Necropsy can be very helpful. Typical findings include thickened intestine, especially in the ileum, enlarged mesenteric lymph nodes, and in severe cases fibrinonecrotic or hemorrhagic intestinal lesions.
Treatment Options for Ileitis in Pigs
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm call or herd-health consultation
- Physical exam and review of age group, manure pattern, and recent stressors
- Isolation or closer observation of affected pigs
- Supportive care such as hydration support, easier access to water, and environmental cleanup
- Targeted fecal PCR for *Lawsonia intracellularis* when testing budget is limited
- Vet-directed medication plan focused on the sickest pigs first
Recommended Standard Treatment
- Full veterinary exam and herd assessment
- PCR testing plus additional fecal or necropsy-based diagnostics as needed
- Vet-directed antimicrobial treatment for affected pigs and sometimes in-feed or water medication for the group
- Supportive care for dehydration, appetite loss, and body condition decline
- Review of feed, stocking density, sanitation, and movement patterns
- Vaccination planning for future control if appropriate for the herd
Advanced / Critical Care
- Urgent veterinary evaluation for hemorrhagic, collapsing, or rapidly deteriorating pigs
- Individual intensive supportive care such as injectable medications, aggressive fluid support, and close monitoring
- CBC/chemistry or additional lab work when available for valuable individual pigs
- Necropsy and histopathology with immunohistochemistry for definitive diagnosis in deaths or complex outbreaks
- Expanded testing for coinfections such as Salmonella or swine dysentery
- Detailed herd-control plan including vaccination, medication timing, and biosecurity redesign
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Ileitis in Pigs
Bring these questions to your vet appointment to get the most out of your visit.
- Does this pig's history and age fit ileitis, or do you think another intestinal disease is more likely?
- Which tests would give the most useful answer right now: fecal PCR, oral-fluid PCR, necropsy, or tissue histopathology?
- Do you suspect coinfections such as Salmonella or swine dysentery, and should we test for those too?
- Which pigs need individual treatment, and when does it make sense to treat the whole group?
- What supportive care changes should we make today for hydration, feed access, pen hygiene, and stress reduction?
- Is vaccination appropriate for this herd, and if so, when should it be given relative to weaning or movement?
- What warning signs mean a pig needs emergency reevaluation right away?
- What is the expected cost range for testing, treatment, and prevention over the next few weeks?
How to Prevent Ileitis in Pigs
Prevention focuses on lowering exposure to Lawsonia intracellularis and reducing the conditions that let it spread. Good manure management, regular cleaning, limiting overcrowding, careful pig flow, and reducing mixing stress all help. Consistent feed and water access also matter, because stressed pigs are more likely to show clinical disease.
Work with your vet on a herd-level plan. Commercial vaccines are available and can be highly effective in reducing disease impact. Vaccination timing should fit the age of risk in your pigs and the rest of the herd's health program, so it is worth reviewing the schedule rather than guessing.
Monitoring is also part of prevention. If pigs are growing poorly, have intermittent loose stool, or there has been a past history of ileitis, your vet may recommend periodic surveillance with PCR or necropsy of losses to catch problems early. Early recognition can prevent chronic intestinal damage and reduce the chance of severe hemorrhagic cases.