Equine keratomycoses in California from 1987 to 2010 (47 cases).
Authors: Reed Z, Thomasy S M, Good K L, Maggs D J, Magdesian K G, Pusterla N, Hollingsworth S R
Journal: Equine veterinary journal
Summary
# Equine Keratomycosis in California: A 23-Year Case Review Between 1987 and 2010, researchers at UC Davis identified 47 horses (48 eyes) with confirmed fungal corneal infections, representing 2% of all ophthalmology cases presented during this period. Diagnoses were established primarily through fungal culture (81% of cases), with Aspergillus species accounting for 64% of isolates; notably, Papulospora—a novel fungal pathogen in equine keratomycosis—was identified in two horses. Medical management alone was attempted in 73% of cases, with medical-surgical combination therapy in 25%, yet overall visual prognosis remained guarded: 77% of eyes were retained but only 53% maintained useful vision, with corneal perforation emerging as a highly significant predictor of blindness (P<0.001). Prior topical anti-inflammatory treatment (used in 43% of cases before presentation) raises important questions about whether corticosteroid use may inadvertently favour fungal proliferation—a consideration that warrants caution when managing corneal ulceration of uncertain aetiology. Given the guarded prognosis and the critical importance of early identification, practitioners should maintain a high index of suspicion for mycotic involvement in chronic, refractory corneal disease, particularly before corneal integrity is compromised, and coordinate promptly with ophthalmology specialists for appropriate diagnostic confirmation and management.
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Practical Takeaways
- •Keratomycosis is uncommon in California horses but should remain on the differential diagnosis for corneal disease; early fungal culture confirmation is critical as 81% of cases were culture-positive
- •Aggressive early intervention is warranted when corneal perforation occurs, as this dramatically worsens visual prognosis—medical management alone may preserve the globe in most cases but not necessarily vision
- •Prior use of topical anti-inflammatory medications (43% of cases) did not prevent progression; consider antifungal therapy as first-line treatment if fungal infection is suspected rather than relying on corticosteroids
Key Findings
- •Keratomycosis comprised 2% of ophthalmology cases at UCD-VMTH over 23 years (47 horses, 48 eyes)
- •Aspergillus was the most common fungal isolate (64% of 44 identified isolates), with a novel Papulospora isolate identified in 2 horses
- •Globe retention was achieved in 77% of cases and vision retention in 53%, with medical-only treatment used in 73% of cases
- •Corneal perforation was significantly associated with loss of vision (P<0.001), serving as a negative prognostic indicator