Equine proliferative enteropathy: a cause of weight loss, colic, diarrhoea and hypoproteinaemia in foals on three breeding farms in Canada.
Authors: Lavoie J P, Drolet R, Parsons D, Leguillette R, Sauvageau R, Shapiro J, Houle L, Hallé G, Gebhart C J
Journal: Equine veterinary journal
Summary
# Editorial Summary: Equine Proliferative Enteropathy in Canadian Foals Lawsonia intracellularis, a transmissible bacterium responsible for proliferative enteropathy, emerged as a significant disease threat in weanling foals across three Canadian breeding farms, presenting with a constellation of clinical signs including rapid weight loss, diarrhoea, colic, depression and characteristic subcutaneous oedema. The research team employed postmortem histopathology (silver staining, immunohistochemistry), PCR analysis of faecal and tissue samples, and serological testing to confirm diagnosis in affected foals, whilst documenting associated haematological abnormalities such as hypoproteinaemia, transient leucocytosis, anaemia and elevated serum creatinine kinase. Most notably, all seven serum samples from affected foals tested positive for L. intracellularis antibodies, and faecal PCR confirmed the organism in six of eighteen foals tested, establishing robust diagnostic markers for field practitioners. Long-acting macrolide therapy—erythromycin estolate, often combined with rifampin—administered for a minimum of 21 days proved highly effective, with survival rates exceeding 95% in treated animals. This landmark study underscores the importance of including proliferative enteropathy in the differential diagnosis when encountering outbreaks of hypoproteinaemia and rapid deterioration in weanling foals, particularly as clinical presentation can closely mimic parasitism and common enteric infections, and demonstrates that early recognition and appropriate antimicrobial intervention can substantially improve outcomes on affected operations.
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Practical Takeaways
- •Include proliferative enteropathy in the differential diagnosis for weanling foals presenting with rapid weight loss, diarrhoea, colic and hypoproteinaemia, particularly in outbreak situations on breeding farms.
- •Consider erythromycin estolate ± rifampin as effective treatment for suspected equine PE, with prolonged therapy (≥21 days) required for clinical recovery.
- •Use faecal PCR and serology (antibody testing) for antemortem diagnosis alongside clinical signs and biochemical findings; hypoproteinaemia is a consistent marker of the disease.
Key Findings
- •Equine proliferative enteropathy caused by Lawsonia intracellularis was identified in foals from 3 breeding farms with clinical signs of depression, rapid weight loss, subcutaneous oedema, diarrhoea and colic.
- •Faecal PCR detected L. intracellularis in 6 of 18 foals (33%), while all 7 serologically tested foals with PE had antibodies against the pathogen.
- •Erythromycin estolate monotherapy or combined with rifampin for minimum 21 days achieved survival in all but 1 foal treated (>94% survival rate).
- •Postmortem confirmation required identification of characteristic intracellular bacteria in intestinal crypt epithelial cells by silver stains, PCR and immunohistochemistry.