Iris abscesses with and without intralenticular fungal invasion in the horse

Antifungal Therapy in Equine Ocular Mycotic Infections

Fungi are clinically important causes of ocular infections in the horse. Keratomycosis is the most common; however, a diverse range of mycotic infections, affecting numerous ocular tissues, may be encountered. Many equine mycoses are diagnostic and therapeutic challenges. Prompt and appropriate treatment is essential to minimize morbidity and reduce the likelihood of vision loss. Knowledge of the characteristics and properties of equine ophthalmology antifungal medications is essential to selecting an optimal treatment strategy, including selection of appropriate medication and effective administration route. Newer delivery methods and devices are available and can contribute to an improved outcome in select situations.

Aspergillus spp. panophthalmitis with intralenticular invasion in dogs: report of two cases

This case series describes the ocular, clinical and histologic manifestations of disseminated Aspergillosis in two dogs. Two dogs presented for severe unilateral panophthalmitis and secondary glaucoma with positive Aspergillus spp. titers. Case 1 showed no clinicopathologic systemic symptoms of fungal dissemination, however, case 2 was affected with acute renal failure. The affected eye of case 1 did not respond to medical therapy and was enucleated for comfort. The affected eye of case 2 responded to aggressive topical and systemic medical therapies, however, the patient was euthanized for acute renal failure. Globes were collected for histologic evaluation at the time of death. Histology of both revealed panophthalmitis with presence of significant intraocular hemorrhage, multifocal fungal granulomas, retinal and optic nerve changes consistent with secondary glaucoma, rupture of the anterior lens capsule, and fungal invasion and colonization of the intralenticular space. These cases represent a unique and devastating ocular manifestation of disseminated Aspergillosis. Cases presenting with uveitis and secondary glaucoma of unknown origin, especially with confirmed or suspected lens capsular rupture, should have serologic testing for this infectious agent.

Equine deep stromal abscesses (51 cases - 2004-2009)--Part 2: the histopathology and immunohistochemical aspect with attention to the histopathologic diagnosis, vascular response, and infectious agents

PURPOSE

To investigate histopathologic and immunohistochemical aspects of equine deep stromal abscesses (DSA) with a focus on the histopathologic diagnosis, presumptive etiology, and the immunohistochemical expression of three angiogenesis-related factors: vascular endothelial growth factor-A (VEGF-A), pigment epithelium-derived factor (PEDF), and interleukin-1 receptor antagonist (IL-1ra).

SAMPLE POPULATION

Paraffin-embedded biopsy samples from 51 DSA. The biopsies were collected from full-thickness penetrating keratoplasty or split-thickness lamellar keratoplasty surgeries at the University of Florida Veterinary Medical Center in the period from 2004 to 2009.

PROCEDURE

The histopathologic and immunohistochemical findings were tested for association between each other. Prevalence calculation and test for association with qualitative data analysis was used for data evaluation.

RESULTS

Fungal hyphae were found histologically in 47.1% (n = 24) of the DSA cases. Histopathologically, most fungal DSA showed suppurative keratitis (n = 34; 66.7%) and little to no stromal vascularization infiltrating the abscess (negative association, P = 0.005). All three angiogenesis-related factors were expressed to some degree in DSA tissue. A negative association between VEGF-A and PEDF when compared to the presence of fungal hyphae (P < 0.001, P = 0.023) indicated that cases positive for these two factors will most probably not have fungal hyphae present.

CONCLUSION

Abnormally decreased VEGF-A expression is suggested as the reason for the slow vascularization and delayed resolution of fungal DSA, whereas PEDF and IL-ra did not seem to have any influence on the vascularization process. Clinical and histopathologic characteristics of DSA make it possible to suggest an etiology for an equine DSA with an unknown etiology.

Mortierella wolfii keratomycosis in a horse

PURPOSE

To describe a case of superficial keratomycosis caused by Mortierella wolfii (M. wolfii) in a horse.

METHODS

A thoroughbred filly was presented with painful right eye of 2 days' duration. A superficial corneal ulcer was observed ventrally together with multifocal punctuate opacities axially. Samples were collected by swabbing and scraping the ulcerated lesion and submitted for microbiologic and cytologic examination.

RESULTS

Microscopic evaluation of debrided corneal tissue revealed the presence of nonseptate fungal hyphae, and culture of a corneal swab yielded fungal growth. Medical treatment with topical antifungal, antibiotic and autogenous serum and systemic anti-inflammatory resolved the problem within 2 weeks.

CONCLUSIONS

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.