Peer-reviewed veterinary case report
Macrodendritic ulcerative keratitis and conjunctival lymphoid hyperplasia in horses with equine herpesvirus-2 and equine herpesvirus-5 infections.
- Journal:
- Veterinary ophthalmology
- Year:
- 2024
- Authors:
- Ledbetter, Eric C et al.
- Affiliation:
- Department of Clinical Sciences · United States
- Species:
- horse
Plain-English summary
This study looked at four young horses, known as foals, that had eye problems caused by infections with equine herpesvirus-2 and equine herpesvirus-5. Each foal had large, superficial ulcers on both eyes and some had thickened areas on the conjunctiva, which is the tissue covering the eye. The veterinarians performed thorough eye exams and took samples from the cornea and conjunctiva to check for the viruses and other issues. They found signs of inflammation and abnormal cells in the corneas, and the viruses were confirmed in the samples. Fortunately, after treating all the foals with antiviral eye drops, their eye problems cleared up completely and did not come back.
Abstract
OBJECTIVE: The aim of this study was to describe the clinical, confocal microscopic, histologic, and virologic features of horses with macrodendritic ulcerative keratitis and conjunctival lymphoid hyperplasia associated with equine herpesvirus-2 and equine herpesvirus-5 infection. ANIMAL STUDIED: Four foals with bilateral ocular disease. PROCEDURES: Complete ophthalmic examination was performed for each horse, and corneal samples were collected for cytology and microbiologic evaluation, including virus isolation and molecular diagnostics for the equine herpesviruses. In vivo confocal microscopy examination of the cornea was performed in two horses. Conjunctival biopsies for histopathology were collected from two horses with nodular conjunctival thickening. RESULTS: Each horse had bilateral, large, superficial dendritic corneal ulcerations that covered extensive regions of the corneal surface. Corneal in vivo confocal microscopy examination in two horses detected inflammatory cells and populations of morphologically abnormal corneal epithelial cells adjacent to the ulcerations. The abnormal epithelial cells included round, relatively small, hyperreflective cells intermixed with elongated, enlarged, hyperreflective cells. Equine herpesvirus-2 was isolated from corneal samples of 2 horses and detected by PCR assay in the other two horses. Equine herpesvirus-5 was also detected by PCR assay in three of the horses. Conjunctival histopathology identified predominantly lymphocytic infiltrates. The macrodendrites and conjunctival masses resolved with topical antiviral therapy (cidofovir or idoxuridine) in all horses and did not recur. CONCLUSIONS AND CLINICAL RELEVANCE: The equine gammaherpesviruses may be associated with the development of macrodendritic ulcerative keratitis and conjunctival lymphocytic masses in foals. In vivo confocal microscopy of horses with macrodendrites revealed similar findings to other host species with herpetic dendritic keratitis.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/38053223/