Ulcerative keratitis is the most frequent corneal and ocular disease of the racehorse in Japan. Careful observation of the eyes after racing is necessary as early diagnosis and treatment of corneal ulcers speeds healing. Many antibiotic have efficacy against the bacterial isolates, however, potent antibiotics should be reserved for the most severe corneal ulcers.

Objective To identify morphologically the locations of equine corneal epithelial stem cells (CESCs) and to culture these cells. Animals studied We studied the eyes of 12 adult thoroughbred horses. Procedures Eye tissues were immunostained for two positive stem cell markers (p63, CK14) and one negative marker (CK3) to identify the locations of CESCs, so we could compare their immunostaining patterns with those of human stem cells previously reported. We compared the proliferation rates and morphological features of epithelial cells isolated from the corneal limbus and central cornea.Results Undifferentiated cells expressing the same immunostaining pattern as human CESCs were present in the equine corneal limbus. Cultured epithelial cells isolated from the limbus expressed the same immunostaining pattern that CESCs show histologically, but cells isolated from the central cornea did not proliferate and could not be evaluated. Conclusions Equine CESCs were localized in the epithelial basal layer of the corneal limbus, where melanocytes reside. They could be cultured without loss of their undifferentiated nature. When collecting such stem cells, it may be useful to harvest and culture corneal epithelial tissues in the limbus where melanocytes serve as an indicator of the collecting area.

Equine keratomycosis comprises a considerable portion of infectious keratitis in Japan, and the causative fungi that we isolated had been isolated previously from horses with keratomycosis in other regions with the exception of M. wolfii. Culture and cytological examination of corneal lesions should be immediately performed on eyes with signs of keratitis, particularly on those not improving with antibacterial medication, as early initiation of aggressive antifungal treatment tended to result in better outcome and shorter treatment period.

SummaryReasons for performing study: It has been suggested that the heel of the horse's hoof expands in the stance phase and this reduces the concussion at impact and helps pump blood into the hoof. Therefore, farriers usually leave a gap in the heel region when using the traditional nailed shoe. Recently glued shoes which are attached firmly to the heel have been developed and these could restrict heel movement.

Increases in HF power indicates that the parasympathetic nervous activity in horses increases during immersion in warm springwater. Thus, immersion in warm springwater may provide a means of relaxation for horses.

A 2-year-old Thoroughbred filly presented with ocular pain and epiphora of the left eye. The pupil was miotic and the cornea edematous near the ventro-temporal limbus, but did not retain any fluorescein. The topical antibiotics and atropine and diclofenac, and systemic flunixin meglumine and antibiotic therapy did not resolve the condition. A pink and fleshy infiltrate developed near the limbus indicating nonulcerative keratouveitis. The anterior uveitis deteriorated as manifested by the presence of dyscoria, hypopyon, and organized fibrin in the anterior chamber. Ocular signs were improved by topical and subconjunctival corticosteroids, but repeatedly deteriorated as the frequency of medication was reduced. The horse was seropositive to three serovars of Leptospira interrogans. The animal was diagnosed as blind on day 91 by the absence of pupillary light and menace reflexes, and donated for histopathologic diagnosis. The corneal opacity was histologically fibrotic and infiltrated predominantly by lymphocytes with Descemet's membrane partially disrupted by macrophages. The choroid was infiltrated by lymphocytes, eosinophils and basophils, and was positive to IgG and C3. There were filamentous or spiral structures positive to Warthin-Starry stain in the renal cortex. There was also polymerase chain reaction amplification of the leptospiral gene in the kidney. From these findings nonulcerative keratouveitis was believed to be caused by systemic infection with Leptospira.

To assess the effect of human interferon-alpha (IFNα) on shipping fever of Thoroughbred racehorses subjected to long-distance transportation, an IFNα preparation was orally administered to 48 horses three times (once daily, 3 successive days) before transportation (IFNα group). In the control group (25 horses), maltose was administered in the same way. These treatments induced no abnormal findings in Thoroughbred racehorses before transportation. Immediately after transportation, significant increases in rectal temperature were observed in both treatment groups, whereas the rectal temperature of the IFNα group tended to be lower than that of the control group. Although WBC, Fbg, and SAA immediately after transportation were significantly increased due to transportation in both groups, the extent of the increases in the IFNα group was significantly smaller than in the control group. Long-distance transportation had a relatively profound impact on Thoroughbred racehorses, which was mitigated by IFNα treatment.

Cytologic evaluation of a corneal scraping was useful to make a clinical diagnosis of keratomycosis. Based on the mycological characteristics, the fungus isolated from the corneal lesion was identified as M. wolfii. To the authors' knowledge, this is the first case report of equine keratomycosis associated with this fungus, although the organism is known to infect various organs of cattle.