Necrotizing Enteritis and Hyperammonemic Encephalopathy Associated With Equine Coronavirus Infection in Equids.
Authors: Giannitti F, Diab S, Mete A, Stanton J B, Fielding L, Crossley B, Sverlow K, Fish S, Mapes S, Scott L, Pusterla N
Journal: Veterinary pathology
Summary
# Editorial Summary: Equine Coronavirus and Fatal Gastrointestinal and Neurological Disease Equine coronavirus (ECoV), a relatively newly recognised pathogen in horses, donkeys and other equids, has emerged across North America, Japan and Europe causing variable clinical presentations—some animals develop fever and enteric signs whilst others show neurological dysfunction. This 2015 pathology study examined two horses and one donkey that died from naturally acquired ECoV infection, using quantitative PCR, immunohistochemistry, transmission electron microscopy and sequencing to characterise tissue damage and confirm viral presence. In the two animals with gastrointestinal disease, severe necrotising enteritis dominated the pathological picture, with extensive villous atrophy, epithelial necrosis, pseudomembrane formation, crypt damage and haemorrhage throughout the small intestine; notably, one horse presented instead with hyperammonaemic encephalopathy characterised by widespread Alzheimer type II astrocytic changes in the cerebral cortex, suggesting the virus can cause profound metabolic derangement secondary to intestinal damage. ECoV antigen was detected in small intestinal tissue across all cases and viral particles measuring 85–100 nanometres were visualised within epithelial cells, with genetic sequencing confirming 97.9–99.0% identity to known ECoV strains. These findings establish ECoV as a cause of both acute, potentially fatal intestinal necrosis and secondary metabolic encephalopathy in equids, highlighting the need for rapid diagnosis in horses presenting with acute enteritis or unexplained neurological signs, particularly during outbreak situations.
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Practical Takeaways
- •ECoV should be considered in differential diagnosis for horses and donkeys presenting with acute severe enteritis, pyrexia, and unexplained neurologic signs (encephalopathy)
- •Recognize that ECoV can present with highly variable clinical manifestations ranging from necrotizing enteritis to primary neurologic disease, complicating clinical recognition
- •Submit small intestinal tissue, contents, or feces for qPCR confirmation and immunohistochemistry when ECoV is suspected, as diagnosis requires laboratory confirmation
Key Findings
- •ECoV was confirmed in 3 equids (2 horses, 1 donkey) presenting with fatal disease using qPCR, immunohistochemistry, and electron microscopy with 97.9-99.0% sequence identity to known strains
- •One horse and donkey developed severe diffuse necrotizing enteritis with villous attenuation, epithelial necrosis, pseudomembrane formation, and microthrombosis
- •One horse developed hyperammonemic encephalopathy with Alzheimer type II astrocytosis, indicating neurologic manifestation of ECoV infection
- •Coronavirus-like particles (85-100 nm enveloped virions with peplomer structures) were identified in small intestinal epithelial cells, confirming viral pathogenesis