Trema micrantha toxicity in horses in Brazil.
Authors: Bandarra P M, Pavarini S P, Raymundo D L, Corrêa A M R, Pedroso P M O, Driemeier D
Journal: Equine veterinary journal
Summary
# Editorial Summary: Trema micrantha Toxicity in Horses Trema micrantha, a tropical plant found in Brazil, poses an underrecognised toxic threat to grazing horses, as demonstrated by two fatal cases presenting with acute neurological deterioration including blindness, incoordination, recumbency and seizure-like activity progressing to death. Post-mortem and histopathological examination revealed severe hepatocellular necrosis alongside cerebral oedema and perivascular inflammation, indicating a dual hepatic and neurological syndrome comparable to documented cases in cattle and sheep exposed to the same plant. The authors identified disseminated haemorrhages affecting multiple organs and characteristic Alzheimer type II astrocytic changes in brain tissue, establishing a distinctive pathological fingerprint for this poisoning. Clinicians in endemic regions should include Trema micrantha toxicity in their differential diagnosis for unexplained equine hepatopathy with concurrent neurological signs, particularly when animals have access to green foliage in pasture or supplementary feed, as early recognition may guide management decisions and inform herd risk assessment.
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Practical Takeaways
- •Trema micrantha toxicity should be considered in the differential diagnosis for equine hepatopathy cases with neurological signs, particularly in Brazil and regions where the plant grows
- •Clinical presentation includes acute onset of neurological dysfunction (blindness, ataxia, recumbency) progressing rapidly to death, warranting immediate investigation of pasture plants
- •Owners and managers should identify and eliminate Trema micrantha from grazing areas where horses have access to green foliage
Key Findings
- •Two horses died after ingesting green leaves of Trema micrantha, presenting with apathy, locomotor deficits, blindness, recumbency, and coma
- •Gross pathology revealed scattered hemorrhages, enhanced lobular liver pattern, and cerebral edema
- •Histology showed disseminated hemorrhages, massive hepatocellular necrosis, neuronal degeneration, and Alzheimer type II astrocytes
- •Clinicopathological findings in horses were comparable to previously documented Trema micrantha poisoning in ruminants