Equine Proliferative Enteropathy (EPE) is a disease predominately of weanling foals in the 3-8 month age group. Although less common, it can also be seen in yearlings and adult horses. It can affect individual animals or can be associated with outbreaks. In some regions the disease can affect up to 10-15% of a foal crop, even on well-managed stud farms. The disease has been reported in numerous countries, including Australia. EPE is caused by the bacteria Lawsonia intracellularis, a Gram negative obligate intracellular organism found in the cytoplasm of proliferative crypt epithelial cells of the jejunum and ileum.
The bacteria causes a similar disease in other species, particularly pigs. It is not uncommon for affected foals to be burdened by concurrent disease or have some obvious recent stress, such as weaning.
Signs
Common signs of EPE include lethargy, rapid weight loss, oedema, diarrhoea, and colic. Poor body condition, a rough hair coat, and ‘potbelly’ appearance are additional reported signs. These signs are not seen in every affected foal, for example, diarrhoea occurs in about 50% of cases.
Diagnosis
Bloodwork features a profound hypoproteinaemia which can be attributed to intestinal loss of albumin, or both albumin and the larger globulin proteins. Typically the serum albumin concentration is less than 20 g/L. This is due to protein loss through the small intestine, decreased absorption and reduced feed intake. This leads to oedema of the ventral thorax and abdomen, limbs, and potentially the head.
Ultrasound reveals thickening of the small intestine.
EPE should be suspected in any weanling foal with weight loss and moderate to severe hypoalbuminemia. Faecal PCR or serology (serum IFA or IMPA) can provide additional support for the diagnosis. Although all tests are specific, they also lack sensitivity. Faecal PCR testing can become negative in affected foals within 4 days of antimicrobial therapy, and antibody responses take time to develop. Carbohydrate absorption testing is usually normal because the lesions are more common in the distal small intestine.
Treatment and Outcomes
Antimicrobial therapy includes azithromycin or clarithromycin; oxytetracycline, doxycycline, or minocycline; metronidazole; or chloramphenicol. Recent reports support the use of intravenous oxytetracycline, followed by oral doxycycline or minocycline. Duration of therapy is typically 2 to 4 weeks.
The use of plasma may be indicated in the oedema becomes a concern, particularly if the gut is involved or the distended skin begins to ooze serum. Corticosteroid therapy is not indicated, as gut inflammation is typically mild.
Survival rates of 82-93% have been quoted.
Tags: Foals; Gastrointestinal diseases