Equine proliferative enteropathy: a cause of weight loss, colic, diarrhoea and hypoproteinaemia in foals on three breeding farms in Canada.

The research investigates a disease outbreak in foals across three breeding farms in Canada, caused by a bacterial infection known as Proliferative enteropathy (PE), or Lawsonia intracellularis, causing symptoms such as rapid weight loss, diarrhoea, colic, and a decrease in plasma proteins (hypoproteinaemia).

Research Focus

• The research focused on studying an outbreak of equine Proliferative enteropathy (PE) that occurred at three breeding farms in Canada.
• PE, a disease caused by Lawsonia intracellularis – a type of intracellular bacteria, was diagnosed in foals (young horses), leading to various symptoms including depression, severe weight loss, subcutaneous oedema, diarrhoea and colic.
• The study also recorded some additional symptoms in the affected foals, like poor body condition, a rough hair coat, a potbellied appearance, respiratory tract infection, dermatitis and intestinal parasitism.

Methods

• The researchers diagnosed PE postmortem on four foals based on the discovery of intracellular bacteria in the apical cytoplasm of expanding crypt epithelial cells in the intestinal mucosa. This diagnosis was made using silver stains, Polymerase Chain Reaction (PCR) analysis, and immunohistochemistry testing techniques.
• For an antemortem (before death) diagnosis of equine PE, assessments were based on clinical signs, hypoproteinaemia evaluations, and exclusion of common enteric (intestinal) infections.

Findings

• Fecal PCR analysis confirmed the presence of L. intracellularis in 6 out of 18 foals tested, indicating that the infection had likely spread among the equine population at the farms.
• Antibodies against L. intracellularis were found in the blood serum of all 7 foals suffering from PE that were evaluated, confirming their infection.
• Mostly, the infected foals were treated with the antibiotic erythromycin estolate, either alone or mixed with rifampin, for a minimum of 21 days.
• While additional symptomatic treatments were administered as necessary, it was found that all but one foal responded positively to the erythromycin treatment and survived the infection.

Conclusion

• The study concludes that PE should be considered in the differential diagnosis of outbreaks causing rapid weight loss, diarrhoea, colic and hypoproteinaemia in weanling foals.
• This is because PE produces symptoms similar to these conditions, which were collectively observed in foals on three different breeding farms in Canada.