Cytologic findings, and feline herpesvirus DNA and Chlamydophila felis antigen detection rates in normal cats and cats with conjunctival and corneal lesions

Samples were collected from 36 cats with feline herpesvirus (FHV-1)-related ocular disease (conjunctivitis, epithelial or stromal keratitis, or corneal sequestration), and 17 cats without ocular changes. Corneoconjunctival swabs, scrapings and biopsies were tested in various combinations for presence of FHV-1 DNA using single round (sr) polymerase chain reaction (PCR) and nested PCR (nPCR). Additional swabs from the inferior conjunctival fornix were tested by enzyme-linked immunosorbent assay for Chlamydophila felis antigen. Cytologic evaluation was carried out on conjunctival (cats with conjunctivitis) and corneal (cats with keratitis) cytobrush preparations. FHV-1 DNA was detected by PCR in 14 (39%) cats with ocular disease and 1 (6%) of the control group. Agreement between srPCR and nPCR results was significant (P < 0.01). FHV-1 DNA was detected in 3/7 cats with conjunctivitis, 5/6 cats with epithelial keratitis, 3/11 cats with stromal keratitis, and 3/12 cats with corneal sequestration. There was a significant association (P = 0.0027) between viral presence and epithelial keratitis. However, no significant association was found between viral presence and conjunctivitis (P = 0.059), stromal keratitis (P = 0.15), or corneal sequestration (P = 0.18). With respect to FHV-1 DNA detection, intersample agreement was significant (P < 0.03). No sampling technique seemed more likely than another to harvest detectable viral DNA, except for cats with corneal sequestrum in which viral DNA was not detected using corneoconjunctival swabs. FHV-1 DNA was detected in 6/9 samples with intranuclear inclusion bodies and in 6/7 cats with eosinophils on cytologic examination. All samples tested negative for C. felis antigen.     

Eosinophilic keratoconjunctivitis in two rabbits

The purpose of this case report is to describe the clinical course and cytologic findings, treatment, and outcome of eosinophilic keratoconjunctivitis in two rabbits. Ophthalmic examination revealed ocular discharge, dacryocystitis, blepharitis, conjunctivitis, white conjunctival and corneal plaques, corneal vascularization, and stromal infiltration with different degrees of severity in each case. In case 2 there was also ulcerative disease of the cornea. Computerized tomography scan of the head, corneal biopsy for histopathologic examination with additional Luna and Giemsa stain were performed in case 2 and conjunctival as well as corneal specimens were obtained for bacteriologic culture and cytologic examination in case 1. Based on test results, a diagnosis of eosinophilic keratoconjunctivitis was made in case 2 and a tentative diagnosis of eosinophilic keratoconjunctivitis was made in case 1. Response to treatment with a topical steroid and topical cyclosporin was supportive of the diagnosis in both cases and shared many similarities with the response to treatment previously described in cats. Eosinophilic keratitis should be considered as part of a differential diagnosis list in rabbits with a history of keratitis.     

Corneal stromal sequestration in a dog

A case of corneal sequestrum in a 9-year-old Shih Tzu is reported. On the ophthalmic examination a brown-pigmented ulcer with mild edema and corneal vascularization was present. The brownish plaque was facing an inferior palpebral tumor. A superficial keratectomy followed by a grid keratotomy and removal of the palpebral mass were performed. Histological findings revealed an inflammatory cell infiltration underneath the acellular stromal layers. No melanin granules were observed. No vascular infiltration was present within the necrotic stroma. The surgical area healed and no recurrence has been reported by the owners at the time of writing. To the authors' knowledge, this is the first report of a corneal sequestrum in a dog.     

Use of conjunctival pedicle grafts in the management of feline keratitis nigrum

Feline keratitis nigrum (necrosis, sequestrum or sequestration) usually presents as a black plaque in the axial or paraxial cornea. Most cats can be treated by excision of the lesion and covering the defect with a third eyelid flap. This technique did not provide satisfactory results in some cases. This paper describes microsurgery using conjunctival pedicle grafting following keratectomy to provide a one step technique to manage recurrent feline keratitis nigrum, feline keratitis nigrum with full thickness lesions of corneal stroma and eyes also affected with keratoconjunctivitis sicca.     

Coccidioides posadasii keratouveitis in a llama (Lama glama)

A 7-year-old male llama was examined for a 3-month history of weight loss, and unilateral keratouveitis. Clinical examination revealed nonulcerative corneal stromal abscessation, corneal vascularization, corneal edema, miosis, posterior synechia, cataract, and fibrin in the anterior chamber of the right eye. The left eye was normal. Histopathology of the right eye following enucleation revealed pyogranulomatous keratouveitis with intralesional fungal spherules consistent with Coccidioides spp. PCR amplification with DNA sequencing confirmed Coccidioides posadasii infection. To the authors' knowledge, this is the first reported case of ocular coccidioidomycosis in a llama.     

Isolation of Feline Herpesvirus 1 from the Trigeminal Ganglia of Acutely and Chronically Infected Cats

Feline herpesvirus 1 (FHV-1) is one of the most common viral infections of domestic cats worldwide, estimated to cause 50% of all respiratory infections in this species. Feline herpesvirus 1 is also an important ocular pathogen of cats, causing conjunctivitis, epithelial and stromal keratitis, symblepharon formation, keratocon-junctivitis sicca, and corneal sequestration. Despite the importance of this viral disease, major questions remain unanswered concerning the pathogenesis of its most important manifestation, the recrudescent infection. Although the taxonomic classification of FHV-1 as an alpha herpesvirus implies the ability of FHV-1 to establish neural latency, attempts at recovering the virus from the trigeminal ganglia of latently infected cats have typically yielded negative results. This failure has stimulated speculation that neural tissue is not an important site for latent FHV-1. However, in the most successful of such studies, FHV-1 was isolated from the trigeminal ganglia of 3 of 17 cats using an explant technique. In the present study, we describe the successful isolation of FHV-1 from the trigeminal ganglia of cats using a similar tissue culture method.     

In vivo confocal microscopy of the normal equine cornea and limbus

Objective  To describe morphologic features, pachymetry and endothelial cell density of the normal equine cornea and limbus by in vivo confocal microscopy.
Animals studied  Ten horses without ocular disease.
Procedure  The central and peripheral corneas were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module using a combination of automated and manual image acquisition modes. Thickness measurements of various corneal layers were performed and endothelial cell density determined.
Results  Images of the constituent cellular and noncellular elements of the corneal epithelium, stroma, endothelium, and limbus were acquired in all horses. Corneal stromal nerves, the subepithelial nerve plexus, and the sub-basal nerve plexus were visualized. Cells with an appearance characteristic of Langerhans cells and corneal stromal dendritic cells were consistently detected in the corneal basal epithelium and anterior stroma, respectively. Median central total corneal thickness was 835 μm (range 725–920 μm) and median central corneal epithelial thickness was 131 μm (range 115–141 μm). Median central endothelial cell density was 3002 cells per mm² (range 2473–3581 cells per mm²).
Conclusions  In vivo corneal confocal microscopy provides a noninvasive method of assessing normal equine corneal structure at the cellular level and is a precise technique for corneal sublayer pachymetry and cell density measurements. A resident population of presumed Langerhans cells and corneal stromal dendritic cells was detected in the normal equine cornea. The described techniques can be applied to diagnostic evaluation of corneal alternations associated with disease and have broad clinical and research applications in the horse.     

Ocular manifestations of feline herpesvirus.

Feline herpesvirus-1 (FHV-1) infection is ubiquitous in the domestic cat population worldwide. The most common clinical ocular manifestations of infection with FHV-1 are conjunctivitis and keratitis. This paper reviews the pathogenesis of feline herpesvirus-1 and discusses the various clinical ocular manifestations, diagnostic techniques and treatment of FHV-1-induced diseases. Ocular manifestations include: conjunctivitis, keratitis, stromal keratitis, keratoconjunctivitis sicca, ophthalmia neonatorium, symblepharon, corneal sequestrum, eosinophilic keratitis and anterior uveitis. Diagnostic techniques discussed include: virus isolation, fluorescent antibody testing, serum neutralising titers, ELISA and polymerase chain reaction. Various therapies are also discussed.     

Tear-deficient and evaporative dry eye syndromes of the horse

Tear-deficient dry eye (keratoconjunctivitis sicca), and evaporative dry eye, with some overlap between these two categories, are two major categories of dry eye recognized in the horse. Careful examination of the eyelid margins, the inner and outer surfaces of the upper and lower eyelids, assessment of blink and third eyelid movement, specific testing of tear production, assessment of corneal sensitivity, and slit-lamp examination of the ocular surface before and after fluorescein dye application is recommended to detect dry eye problems. Rose Bengal dye application is also recommended in many cases. Facial nerve paresis is a possible complicating factor in some instances. Evaporative dry eye deserves closer scrutiny for it may be a contributory factor when ocular surface disease such as keratomycosis is present. Factors which influence ocular surface health need more close examination in horses.     

Diagnosis and management of chronic corneal epithelial defects (indolent corneal ulcerations)

Chronic corneal epithelial defects (CCEDs; indolent corneal ulcerations) are the most common refractory ulcerations in veterinary medicine and are diagnosed by their classic appearance. CCEDs are superficial ulcerations without stromal involvement and have a nonadherent epithelial border (lip). Fluorescein stain adheres to the exposed stroma and extends below the epithelial border, outlining the epithelial lip. CCEDs occur secondary to adnexal disease, keratoconjunctivitis sicca, exposure keratitis, neurotrophic keratitis, and primary corneal disease. In cats, herpes keratitis is associated with the development of CCEDs. Bacterial infections are not responsible for the refractory nature of CCEDs. Because of the refractory nature of CCEDs, treatment can be frustrating for both owner and veterinarian. Current treatment recommendations consist of identifying and treating the underlying cause and performing procedures that stimulate epithelialization and adhesion of the corneal epithelium. Initial treatment of CCEDs includes ulcer debridement and grid keratotomy. Superficial keratectomy is indicated in refractory cases.     

Therapy of ocular and visceral leishmaniasis in a cat

An 8-year-old, spayed female Domestic Short-haired cat was referred for further evaluation of chronic lymphocytic-plasmacytic stomatitis and bilateral ocular disease. The cat had been treated with systemic glucocorticoids for several months. Initial ophthalmic examination revealed bilateral deep stromal corneal ulcers, exudative panuveitis and secondary glaucoma. Mature mild neutrophilia and monocytosis were detected on complete blood cell count. Abnormalities in the serum profile were hyperglycemia, mild azotemia, hyperglobulinemia and moderate polyclonal gammapathy. Urinalysis revealed glucosuria without ketonuria. Diabetes mellitus was diagnosed and treatment with long-acting insulin was started. An enzyme-linked immunosorbent assay was highly positive for leishmaniasis, and treatment with allopurinol was started. Although specific topical treatment was applied, melting ulcers progressed to corneal perforation and both eyes were enucleated. Ocular histology showed large numbers of intracellular organisms compatible with amastigotes of the genus Leishmania located in the uveal tract, cornea, sclera and retina. Results of inmunohistochemistry staining on ocular samples were positive for Leishmania. Bone marrow cytology demonstrated numerous macrophages with intracytoplasmatic Leishmania. Polymerase chain reaction results on bone marrow for Leishmania were positive. Three weeks later, hypoglycemic episodes permitted withdrawal of the insulin therapy. To the authors' knowledge this is the first case of ocular and visceral leishmaniasis diagnosed in vivo and under systemic treatment in a cat.     

Feline corneal disease

The cornea is naturally transparent. Anything that interferes with the cornea's stromal architecture, contributes to blood vessel migration, increases corneal pigmentation, or predisposes to corneal edema, disrupts the corneas transparency and indicates corneal disease. The color, location, and shape and pattern of a corneal lesion can help in determining the underlying cause for the disease. Corneal disease is typically divided into congenital or acquired disorders. Congenital disorders, such as corneal dermoids are rare in cats, whereas acquired corneal disease associated with nonulcerative or ulcerative keratitis is common. Primary ocular disease, such as tear film instability, adenexal disease (medial canthal entropion, lagophthalmus, eyelid agenesis), and herpes keratitis are associated with the majority of acquired corneal disease in cats. Proliferative/eosinophilic keratitis, acute bullous keratopathy, and Florida keratopathy are common feline nonulcerative disorders. Nonprogressive ulcerative disease in cats, such as chronic corneal epithelial defects and corneal sequestration are more common than progressive corneal ulcerations.     

Corneal stromal abscess in a horse

A thoroughbred yearling presented with a focal, yellow, midstromal corneal opacity with concurrent iridocyclitis which was consistent with a corneal stromal abscess. When continued, appropriate, medical therapy failed to improve the patient's condition, penetrating keratoplasty was performed for diagnosis and therapy. Histopathology showed that the deep corneal stroma and Descemet's membrane were severely infiltrated with necrotic neutrophils and numerous, intralesional fungal hyphae. Culture was negative. Bacteria were not isolated, consistent with a fungal corneal stromal abscess. The resultant corneal scar did not interfere with the horse's racing career.     

Isolation and cultivation of equine corneal keratocytes, fibroblasts and myofibroblasts

Objective  To establish an in vitro model for the investigation of equine corneal wound healing. To accomplish this goal, a protocol to isolate and culture equine corneal keratocytes, fibroblasts and myofibroblasts was developed.
Animal material  Equine corneal buttons were aseptically harvested from healthy research horses undergoing humane euthanasia for reasons unrelated to this study. Slit-lamp biomicroscopy was performed prior to euthanasia by a board-certified veterinary ophthalmologist to ensure that all samples were harvested from horses free of anterior segment disease.
Procedure  Equine corneal stroma was isolated using mechanical techniques and stromal sub-sections were then cultured. Customized media at different culture conditions was used to promote growth and differentiation of corneal stromal cells into keratocytes, fibroblasts and myofibroblasts.
Results  Cell culture techniques were successfully used to establish a method for the isolation and culture of equine corneal keratocytes, fibroblasts and myofibroblasts. Immunohistochemical staining for alpha-smooth muscle and F-actin was used to definitively differentiate the three cell types.
Conclusion  Equine corneal stromal keratocytes, fibroblasts and myofibroblasts can be predictably isolated and cultured in vitro using this protocol.     

A retrospective survey of the ocular histopathology of the pinniped eye with emphasis on corneal disease

Objective A retrospective review of globes from 70 pinnipeds submitted to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) describing the type and frequency of ocular disease. Animals studied The study included 50 California sea lions, four animals listed only as ‘sea lion’, nine Northern elephant seals, five harbor seals, 1 Northern fur seal, and 1 Hooded seal. Procedures Globes were classified by microscopic findings. Categories were not mutually exclusive. Results The largest category was corneal disease (63 globes from 40 pinnipeds). The second largest was cataractous changes (35 globes from 23 pinnipeds). Additional ocular diseases included traumatic ocular injuries (nine globes from eight animals), phthisis bulbi (nine globes from eight pinnipeds), neoplasia (nine globes from six adult California sea lions), amyloid deposition in the corneal stroma, ciliary body, or both locations (five globes from four pinnipeds), and fungal disease (three globes from two pinnipeds). Pinnipeds with corneal disease were further categorized: stromal pathology (39 globes from 27 pinnipeds); epithelial pathology (37 globes from 27 pinnipeds); Descemet’s pathology (11 globes from eight pinnipeds); endothelial attenuation or absence (33 globes from 22 pinnipeds); presence of retrocorneal membranes (15 globes from 10 pinnipeds); anterior synechia (eight globes from six animals), and keratitis (seven globes from five pinnipeds). Conclusions This is the first report of ocular amyloid in pinniped eyes. All cases of neoplasia were in a pattern suggesting metastatic disease. In this study, there was a higher prevalence of ocular disease in captive pinnipeds, particularly in the posterior cornea.     

Superficial stromal keratitis in the dog

Superficial stromal keratitis or pannus is a syndrome of corneal, conjunctival and third eyelid inflammation. Superficial stromal keratitis mainly presents as a subepithelial corneal infiltration of vascular connective tissue, and usually arises from the lateral (temporal) limbal area. In some dogs perilimbal hyperaemia and third eyelid blepharitis can be present without corneal involvement. The most commonly affected breed of dog is the German Shepherd. Most cases of superficial stromal keratitis can be controlled with topical corticosteroids, and only rarely is cryosurgery or superficial keratectomy required to remove excessive pigment and or granulation tissue. The precise aetiology of SSK is unknown, but is likely to be multifactorial, with sunlight being a significant factor. Corneal lipidosis and keratoconjunctivitis sicca can occur secondary to superficial stromal keratitis.     

Episcleral cyclosporine A implants for the management of unilateral keratoconjunctivitis sicca in an 8‐year‐old mare

An 8‐year‐old mare was presented for investigation of a 1‐month history of blepharospasm, eyelid swelling, corneal edema, and ocular discharge of the right eye (OD). Ophthalmic examination confirmed mucopurulent ocular discharge, conjunctival hyperemia, and a dry, dull appearance to the cornea OD. Schirmer tear test results confirmed an absence of tear production OD (0 mm/min) consistent with keratoconjunctivitis sicca. Treatment with topical 0.2% cyclosporine A resulted in an improvement in clinical signs. An episcleral cyclosporine A implant was placed under standing sedation 5 days after initial presentation. Re‐examination 9 days post‐operatively confirmed that the mare's tear production in the right eye had improved and no further clinical signs had been observed. Topical medications were gradually discontinued. Re‐examinations performed up to 12 months postsurgery showed no recurrence of clinical signs and no adverse effects of the implant. To our knowledge, this is the first report of the use of a cyclosporine A implant in the management of KCS in a horse and highlights its potential as an effective, alternative therapy in the management of KCS in horses.     

Acremonium keratomycosis in a cat

A 14-year-old, female spayed Domestic Short-haired cat was presented for evaluation of progressive superficial corneal ulceration with mucoid ocular discharge, blepharospasm, and conjunctival hyperemia OD. Upon examination, ulcerative keratitis with stromal loss, chemosis, corneal edema, miosis, aqueous flare, and hyphema were noted. Corneal cytology revealed branching, septate fungal hyphae with bulbous terminations and associated ovoid structures, with suppurative inflammation. Fungal culture of corneal swabs confirmed the presence of Acremonium, although PCR of the cytology sample was negative. Ten days of treatment with topical 1% miconazole resulted in clinical deterioration before switching to topical 1% voriconazole solution, which was successful in resolving the infection. The apparent clinical efficacy of the topical antifungals used contrasted with the in vitro susceptibility profile.     

Keratoconus in a cynomolgus monkey

In a seven-year-old male cynomolgus monkey, erythema of the upper eyelid and forehead and corneal opacity, edema and conical protrusion in the eye were observed. At necropsy, ophthalmological and serological examinations revealed binocular corneal opacity and conical protrusion and a high IgE level, respectively. Thinning of the epithelium and stroma of the cornea were noted histopathologically. At the center of the corneal epithelium, the number of epithelial cells was reduced, their cytoplasm was poorer and the basal cells were flatter than at the periphery. Bowman's membrane was folded with partial loss or breakage. Collagen fibers were compacted or disarranged, and the keratocytes were increased in the stroma, with focal pyknosis or loss of the endothelium and folding of Descemet's membrane. Electron microscopical examination revealed atrophy of the corneal epithelial basal cells. This is the first report of a case of keratoconus in a cynomolgus monkey.