Treating Equine Proliferative Enteropathy

If a foal comes down with signs of equine proliferative enteropathy (EPE), confirm the diagnosis, treat the affected foal, and monitor the herd for additional cases, Connie Gebhart, PhD, said at the 2010 ACVIM Forum, held June 9-12 in Anaheim, Calif.

Clinical signs include peripheral swelling, weight loss or slow growth, lethargy, loss of appetite, fever, colic, diarrhea, and low blood protein levels. Serum and fecal samples must be collected to confirm the diagnosis.

EPE usually occurs in weaned foals younger than 12 months of age, although occasionally it is seen in adult horses. Because of its link to weaning, most U.S. cases occur from September to December.

"We rarely diagnose it in a horse that hasn't been weaned," said Gebhart, associate professor at the University of Minnesota, "but we don't know if that is because of the stress of weaning or a change in the foal's immune status."

A history of recent transport, which could be linked to stress, is also common among infected foals.

"Usually the disease is self-limiting, although sometimes it can be chronic, and sometimes, the horses must be euthanized due to extreme weight loss," Gebhart said. "These foals are just poor doers."

EPE can be difficult to diagnose based on clinical signs alone, and veterinarians should send blood and/or fecal samples to a diagnostic laboratory to look for the Lawsonia intracellularis bacteria to confirm the diagnosis.

Foals respond best if treated early with antibiotics. "Macrolides (+/- rifampin) are effective in horses, and they will clear the infection, but if you wait too long, the damage [to the intestinal tract] is done," she said.

Doxycycline, choramphenicol, or oxytetracycline can also be used. Horses also need supportive care, such as intravenous fluids, plasma transfusions, parenteral nutrition and anti-ulcer drugs.

Treated foals sell for an average of 68% less than the average price of an unaffected foal by the same stallion, she added.

"Up to 65% of herd mates are positive after identification of a clinical case in a herd," she said, so monitor the rest of the weanlings to identify more cases.

  • Check foals for early clinical signs (depression, anorexia, peripheral edema);
  • Collect serum samples monthly for all weaned foals up to 12 months of age and test for protein levels and/or serology;
  • Also collect manure for PCR from any foals with clinical signs; and
  • Send any animals that died from EPE to a laboratory for necropsy.

There is no equine vaccine, but Boehringer Ingelheim Vetmedica distributes Enterisol Ileitis, a swine vaccine, which protects vaccinated pigs.

Vaccine studies in horses are only just beginning, but a study reported here by Nicola Pusterla, DVM, Dipl. ACVIM, at UC Davis, found that the vaccine was safe in horses when given orally or rectally and induced an immune response.

About the Author

Marie Rosenthal, MS

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