Hepatic Dicrocoelium dendriticum infection in a miniature horse.

This study reports on the first identified case of a liver infection by the parasite Dicrocoelium dendriticum in a miniature horse from North America.

Background of the Study

• The study concerns an investigation into the cause of death of a miniature horse from an Ontario farm, which had to be euthanized due to its poor health condition. The horse was emaciated and showed signs of serous atrophy of fat, an indication of severe weight or muscle loss.

Key Findings

• Upon post-mortem examination, evidence of hepatic atrophy and moderate periportal fibrosis was observed. Hepatic atrophy refers to the wasting away of the liver, while periportal fibrosis is the formation of excessive fibrous tissue in the liver, often due to inflammation or injury.
• The researchers also found eggs and trematodes in the horse’s liver. The trematodes were identified as Dicrocoelium dendriticum, a type of flatworm that primarily affects the liver of various mammals.
• This discovery is significant, as it marked what is believed to be the first reported case of Dicrocoelium dendriticum infection in equids (horses, donkeys, zebras, etc.) on the North American continent. Previously, this type of infection is more commonly documented in sheep and cattle and rarely in horses.

Implications and Conclusion

• The findings stress the need to include Dicrocoelium dendriticum infection as a potential differential diagnosis when examining unexplained liver disease in equids, particularly in North America.
• The Dicrocoelium dendriticum infection could potentially be an emerging health concern in the North American horse population, and more studies are needed to understand the characteristics, prevalence, and risk factors associated with this parasitic infection in equids in this region.