Proliferative Hemorrhagic Enteropathy in Pigs: Sudden Bleeding from Ileitis

Proliferative hemorrhagic enteropathy, often called PHE, is a severe and sudden form of porcine ileitis. It is linked to Lawsonia intracellularis, a bacterium that infects cells lining the intestine. In this form of disease, the lower small intestine becomes thickened and fragile, and pigs can bleed into the gut very quickly.

This condition is most often reported in older growing pigs, replacement gilts, and young adults, rather than very young piglets. Some pigs are found dead with little warning. Others show weakness, pale skin, dark or bloody manure, or a rapid drop in appetite and activity over a short period.

PHE is part of the broader disease group called porcine proliferative enteropathy. Other forms may cause chronic diarrhea and poor growth, but the hemorrhagic form is more dramatic and more dangerous. Because blood loss can be severe, fast veterinary involvement matters.

For pet pigs and small herds, this can feel especially alarming because the change may happen within hours. Your vet can help confirm whether ileitis is the likely cause and guide both emergency care for the sick pig and prevention steps for other pigs in contact.

The underlying cause is infection with Lawsonia intracellularis, an obligate intracellular bacterium. It spreads mainly by the fecal-oral route, meaning pigs pick up the organism from manure-contaminated environments, equipment, boots, water, or direct contact with infected pigs. The bacterium targets intestinal cells and causes abnormal thickening of the intestinal lining.

Not every infected pig develops the hemorrhagic form. Disease expression depends on several factors, including age, exposure level, stress, stocking density, sanitation, mixing of pigs, and whether other intestinal infections are present. In many groups, Lawsonia causes milder poor-growth or diarrhea problems first, while a smaller number of pigs develop sudden bleeding.

PHE tends to affect older growing pigs and young adults, especially when immunity is incomplete or herd exposure pressure is high. Mixed infections can also complicate the picture. Your vet may want to rule out other causes of bloody diarrhea or sudden death, such as Salmonella or swine dysentery, because these can occur at the same time.

For pet pigs, risk can rise when new pigs are introduced without quarantine, manure control is poor, or pigs are exposed to contaminated housing. Good management does not remove all risk, but it can lower the chance of a severe outbreak.

Diagnosis starts with the story and the pattern. Your vet will consider the pig’s age, sudden weakness or death, dark or bloody manure, and whether other pigs in the group are affected. On exam, a sick pig may look pale, weak, dehydrated, or in shock. Bloodwork may show anemia from blood loss.

Testing often includes fecal PCR or intestinal tissue testing for Lawsonia intracellularis. However, a positive fecal test alone does not always prove that Lawsonia is the cause of severe disease, because the organism can be present in herds without causing the hemorrhagic form at that moment. That is why your vet may combine lab results with clinical signs and herd history.

A definitive diagnosis is strongest when Lawsonia is detected directly in intestinal lesions, usually through histopathology with special staining or immunohistochemistry on tissue samples. If a pig dies, necropsy can be very helpful. Typical findings may include a thickened lower small intestine and blood within the intestinal contents.

Your vet may also recommend testing to rule out other important causes of enteric disease, especially Salmonella infection and swine dysentery. In herd situations, this broader workup helps guide treatment choices and prevention planning for the rest of the pigs.

Prevention focuses on lowering exposure to Lawsonia intracellularis and reducing the stressors that let ileitis spread. Good manure management, regular cleaning of feeders and waterers, avoiding overcrowding, and limiting mixing of age groups can all help. New pigs should be quarantined before joining the group, especially in small herds and pet pig homes.

Vaccination can be an important option in some settings. Commercial Lawsonia vaccines are available for swine, including oral live and injectable products, and your vet can help decide whether they fit your herd size, age group, and disease history. Vaccination does not replace sanitation, but it can reduce disease impact and shedding.

Because Lawsonia is common in pig populations, prevention is usually a herd strategy, not a one-time fix. Your vet may recommend reviewing feed changes, stocking density, movement patterns, and timing of stress events like transport or regrouping. Consistent routines often help more than dramatic short-term changes.

If your pig has had ileitis before, or if another pig on the property died suddenly, ask your vet about a practical prevention plan. That may include quarantine, targeted diagnostics, medication protocols for outbreaks, and a vaccination schedule tailored to your situation.