Equine proliferative enteropathy (EPE)

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Equine Proliferative Enteropathy (EPE)

Lawsonia Intracellularis, Proliferative Enteritis

Equine proliferative enteropathy (EPE) is an important intestinal disease of young foals, caused by a bacteria called Lawsonia intracellularis. The disease was first reported in horses in 1982. EPE is found worldwide, with cases reported in North and South America, Africa, Australia, and Europe. Foals with EPE will most often develop noticeable swelling (edema) under the skin, particularly in between the front legs, scrotal area in colts, at the throatlatch, and occasionally in the lower portions of the legs. Other clinical signs that are similar to several other gastrointestinal diseases of foals include fever (101.3°F (38.5°C)), loss of appetite, rough hair coat, diarrhea, colic, and weight loss. Foals with EPE may also have concurrent disorders such as gastric ulcers, intestinal parasites, and respiratory tract infection.

L. intracellularis is thought to be transmitted by fecal-oral route, from infected animals that shed the organism within their feces. Several domestic and wild animals are known to be carriers of the organism, which act as reservoirs, the most important being rabbits, dogs, cats, mice and rats. Exposure to pig feces is another potential source of infection for horses. L. intracellularis can survive for 1 to 2 weeks in the environment during the winter season.


Loss in appetite
Fever (>101.3°F (38.5°C))
Swelling between the front legs, throatlatch, sheath, and distal limbs
Mild to severe diarrhea
Weight loss


  • History
  • Clinical signs
  • Abdominal Ultrasound - Thickened intestinal wall
  • Total Protein - Low total protein level, usually less than 5.0 g/dL, and albumin less than 2.0 g/dL.
  • Lawsonia intracellularis culture/PCR
  • Intestinal biopsy
  • Histopathology



Supportive careIntravenous (IV) fluids, anti-ulcer drugs, parenteral nutrients, plasma transfusion
Antimicrobialssuch as macrolides, alone or in combination with rifampin, chloramphenicol, oxytetracycline, or doxycycline, administered for 2 to 3 weeks.


  • Vaccination
  • Don't house pigs near horses
  • Practice good rodent control
  • Biosecurity


Reported survival rates for affected horses with appropriate treatment range from 81 to 93%.

Scientific Research

General Overviews

Age Range

affects mainly young horses (between 2 to 9 months of age)

Risk Factors

  • High rodent populations near where horses are kept or feed is stored
  • Housing pigs on the same premises as horses