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.     

Equine keratomycoses in California from 1987 to 2010 (47 cases)

Reasons for performing study: Equine keratomycosis in the western USA has received little study, probably owing to its low prevalence. Objectives: To determine clinical features, predominant fungal isolates, treatment modalities and outcomes of horses with keratomycosis in California and compare these with results from different geographic regions. Methods: Records of horses presented to the University of California‐Davis Veterinary Medical Teaching Hospital (UCD‐VMTH) with confirmed keratomycosis between 1987 and 2010 were reviewed for this retrospective study. Information retrieved from the record included background, ophthalmic examination findings, treatment prior to and following presentation, visual outcome, and ocular survival. Results: A total of 48 eyes in 47 horses met the inclusion criteria and comprised 2% of cases presented to the UCD‐VMTH ophthalmology service. Prior to presentation, 20 horses (43%) received at least one topically administered anti‐inflammatory medication. Keratomycosis was confirmed by fungal culture in 38 horses (81%), by histopathology in 2 horses (4%) and by cytology in 7 horses (15%). Forty‐four isolates were identified in the 38 horses cultured; Aspergillus was the most common isolate (64%) and a novel isolate, Papulospora, was identified in 2 horses. Treatment consisted of medication only (73%), medical and surgical treatment (25%), or immediate enucleation (2%). Globe retention was 77% and vision retention was 53%. Corneal perforation was significantly associated with loss of vision (P<0.001). Conclusions: Keratomycosis is relatively uncommon in horses presented for ophthalmic conditions at UCD‐VMTH. Corneal perforation was a negative prognostic indicator for vision in this population of northern Californian horses.     

Clinical findings and progression of 10 cases of equine ulcerative keratomycosis (2004–2007)

Ulcerative keratomycosis is a serious sight‐threatening disease of horses and the veterinary literature is replete with cases of poor visual outcome following this condition. During a 3 year period, 10 horses were treated for confirmed keratomycosis at the Veterinary Teaching Hospital (VTH) of the University of Cordoba (Spain). Ulcerative keratomycosis accounted for an average of 8.62% of the total equine ophthalmic admissions during this time and an average of 33.3% of horses were diagnosed with infectious keratitis. Fungi were diagnosed using cytology (n = 4) and/or culture (n = 8) and histopathology (n = 1). Aspergillus sp. was the most commonly isolated fungus. Medical therapy alone or combined medical and surgical treatment was utilised for therapy depending on the clinical condition. Miconazole 1% was the most common topical antifungal therapy employed. Median duration of treatment was 73.12 days. Records were evaluated to determine visual outcome and globe survival.     

Equine keratomycosis in Japan

Objective To describe the incidence, clinical progress, visual outcome, and laboratory findings of equine keratomycosis in Japan. Procedure Retrospective study of the medical records of horses clinically and mycologically diagnosed with keratomycosis at the Equine Hospitals of the Japan Racing Association from 2005 to 2011. Results The diagnosis of keratomycosis was confirmed in eight horses (40.0% of the 20 horses with infectious keratitis from which fungi and/or bacteria were isolated). Fungi recovered from corneal swabs were identified as Aspergillus flavus (4), Aspergillus niger (1), Fusarium solani (1), and Mortierella wolfii (2). All horses were treated medically with topical antifungals, and one horse was also treated surgically. The median of treatment period was 40 days. Two horses were rendered blind in the affected eye and the others retained vision. Conclusions 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.     

Keratitis due to microfilariae in dogs: a newly recognized disease

Parasitic agents have been associated with keratitis, but a diagnosis of parasitic keratitis has not been commonly made in domestic animals. The purpose of this study was to describe the clinical and histopathological findings in seven dogs with chronic keratitis caused by microfilariae diagnosed in Brazil. All dogs presented with superficial corneal opacities of varying degrees affecting the perilimbal and central regions of the cornea, with other opaque areas appearing as crystalline deposits and corneal vascularization. The lesions were bilateral and were associated with mild‐to‐moderate conjunctival hyperemia. There was no history of blepharospasm or pruritus, and no subjects presented with epithelial erosions. Corneal biopsy revealed free microfilariae in the corneal stroma, with varying degrees of inflammation and collagen fiber destruction. The microfilariae were also found in skin lesions by skin snip technique. No adult worms were found in these dogs, and no dogs were on heartworm preventative before diagnosis. Monthly doses of oral ivermectin improved ocular and dermal lesions. One dog showed complete remission with the treatment. The species of the microfilariae was not identified.     

Third eyelid dermoid in a horse

An 8‐year‐old Gypsy Vanner gelding presented to the University of Florida Ophthalmology service for the evaluation of chronic, recurrent corneal ulcers behind the third eyelid of the right eye. On ophthalmic examination, a cluster of aberrant hairs was identified growing along the margin of the third eyelid. This portion of third eyelid was surgically excised, and histopathology identified the haired tissue as a dermoid. Chronic keratitis secondary to a third eyelid dermoid was diagnosed, and excision appeared curative at 6 months post‐operative follow‐up.     

Subconjunctival voriconazole for the treatment of mycotic keratitis in a horse

Fungal keratitis in the horse is a common but challenging disease. This report describes the successful treatment of Fusarium keratitis with both topical and subconjunctival voriconazole 1%. Voriconazole is a new triazole antifungal that has demonstrated efficacy against common fungal pathogens. Topical voriconazole is able to penetrate the intact corneal epithelium making it a good choice for superficial or deep mycotic keratitis. Reports of subconjunctival use of antifungal drugs are sparse in the veterinary literature. We found subconjunctival voriconazole was well tolerated and easy to safely administer.     

Osseous metaplasia in the conjunctiva of a horse presenting with recurrent ulcerative keratitis

A 13‐year‐old Thoroughbred gelding presented with a 6 month history of recurrent conjunctivitis, dacryocystitis and corneal ulceration affecting the left eye (OS). Treatment had included multiple topical antibiotic and anti‐inflammatory preparations, nasolacrimal system flushing and an injection of methylprednisolone acetate (MPA) (Depomedrone) ¹ administered subconjunctivally into the left lower eyelid. No mechanical cause for the ulcerative keratitis could be visualised but digital palpation revealed a firm linear structure in the central palpebral conjunctiva of the lower eyelid. An excisional biopsy was performed and histopathological examination revealed the lesion to be a region of osseous metaplasia. Following excision of the lesion, the corneal ulcer resolved and the eye remained disease free over a 4 year follow‐up period. A causal link between the osseous metaplasia and the recurrent ulcerative keratitis was therefore suspected. This report describes the management of this case and discusses the pathogenesis of osseous metaplasia and the use of subconjunctival corticosteroids.     

Cutaneous fungal granulomas due to Alternaria spp. infection in a horse in New Zealand

Equine cutaneous fungal granulomas have been previously referred to in New Zealand (Fairley 1998), and are described in the veterinary literature from around the world, including North America and Australia (Pascoe and Summers 1981; Genovese et al. 2001; Valentine et al. 2006), but no peer-reviewed reports appear published in the literature in New Zealand. Described here is a case of multiple cutaneous fungal granulomas caused by Alternaria spp. in a horse in New Zealand.     

Splenic abscesses due to migrant metallic wires from small intestine in a horse

This reports discusses a perforating metallic wire that was suspected of causing chronic weight loss, inappetance and pyrexia in a 15‐year‐old Standardbred gelding, due to the fact that during the previous 18 months, 6 horses coming from the same yard were referred for recurrent or acute colic related to the ingestion of metallic wires. Splenomegaly was detected ultrasonographically and confirmed during surgery. During necropsy, 2 metallic wires 0.2 mm in diameter and 3–4 cm long were found in a markedly enlarged spleen with several nonencapsulated abscesses. Metallic wire perforation and migration through the lower alimentary tract may involve different abdominal quadrants (intestine, abdominal wall, spleen, liver) and lead to different clinical syndromes as acute or recurrent colic and weight loss. A clinical diagnosis is challenging as the clinical signs are often nonspecific and prognosis is generally considered poor.     

Bilateral third eyelid ectopic cilia in an adult horse

A 15‐year‐old Cob mare presented with a 4‐month history of chronic epiphora and intermittent blepharospasm in the right eye. On ophthalmic examination, two translucent aberrant hairs were identified at the third eyelid margin corresponding to an area of corneal fibrosis and neovascularization. Partial excision of the third eyelid was performed, and histopathology confirmed ectopic hair follicles. Two weeks later, clinical signs recurred in the same eye. Examination revealed another pair of aberrant hairs on the bulbar surface of the third eyelid near its leading edge. This portion of the third eyelid was also excised, and histopathology confirmed two additional ectopic hair follicles. Eight months later, the horse developed similar clinical signs in the left eye. Ophthalmic examination showed a single aberrant translucent hair at the third eyelid margin associated with focal fibrosis and neovascularization of the ventromedial cornea. Partial excision of the third eyelid was performed, and histopathology confirmed an ectopic hair follicle within the third eyelid conjunctiva. Excision was curative at 4 years postoperatively with no further recurrence in either eye.     

Mycotic keratitis in a horse caused by Aspergillus fumigatus. The first reported case in Finland.

The first identified Finnish case of equine mycotic keratitis caused by Aspergillus fumigatus is described. The clinical picture, the sampling method, the macro- and micromorphology of the causative fungus and the therapy applied are reported in detail. Therapy with natamycin (Pimafucin 2.5% eyedrops. Gist-Brocades) was successful.     

Curvularia keratomycosis in a dog

A 10‐year‐old, spayed female Bichon Frise was referred to the Veterinary Medical Center of the University of Florida with a 6‐week history of blepharospasm and a nonhealing ulcer of the left eye. Ophthalmic examination revealed a 3–4 mm diameter corneal ulcer with faint edema at the lesion edge, and a raised grayish area on the paraxial cornea near the 2 o’clock position. Cytological testing revealed fungal hyphae and extracellular cocci. Culture of the lesion found heavy growth of Enterococcus faecalis and Curvularia spp. Treatment with a combination of topical antibiotics (polymyxin B, sulfate/trimetoprim, and 10% sulfacetamide sodium), 1% miconazole, autologous serum, and 5% hypertonic saline was instituted. After 8 days of medical therapy, an improvement of clinical signs was noted, and 15 days after initiation of treatment, the ulcer was healed with minimal corneal scarring.     

In vivo confocal microscopy of equine fungal keratitis

Objective To describe in vivo corneal confocal microscopy of horses with fungal keratitis and correlate findings with clinical, histopathological, and microbiological evaluations of clinical cases and an ex vivo experimental equine fungal keratitis model. Animals studied A total of 12 horses with naturally‐acquired fungal keratitis and ex vivo equine corneas experimentally infected with clinical fungal isolates. Procedures Horses with naturally‐acquired fungal keratitis were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module. Confocal microscopy images of clinical isolates of Aspergillus fumigatus, Fusarium solani, and Candida albicans were obtained by examination of in vitro cultures and experimentally infected ex vivo equine corneas. Results Non‐specific in vivo corneal confocal microscopic findings in horses with fungal keratitis included leukocyte infiltrates, activated keratocytes, anterior stromal dendritic cell infiltrates, and vascularization. Linear, branching, hyper‐reflective structures that were 2–6 μm in width and 200 to >400 μm in length were detected in all horses with filamentous fungal keratitis. Round to oval hyper‐reflective structures that were 2–8 μm in diameter were detected in a horse with yeast fungal keratitis. The in vivo confocal microscopic appearance of the organisms was consistent with fungal morphologies observed during examination of in vitro cultures and infected ex vivo equine corneas. Conclusions In vivo corneal confocal microscopy is a rapid and non‐invasive method of diagnosing fungal keratitis in the horse. This imaging technique is useful for both ulcerative and non‐ulcerative fungal keratitis, and is particularly advantageous for confirming the presence of fungi in deep corneal stromal lesions.     

Evidence‐based considerations for control of Parascaris spp. infections in horses

Parascaris spp. infection is virtually ubiquitous in young foals and worm burdens can achieve high numbers. The most important disease manifestation is impaction of the small intestine, which occurs in a small proportion of infected foals but is associated with a guarded prognosis for survival. Control of Parascaris spp. is complicated by emerging resistance to currently available anthelmintic drug classes. Resistance to macrocyclic lactones has been reported worldwide and a few studies have also documented signs of resistance to pyrantel salts and benzimidazoles. Foals generally develop immunity to Parascaris spp. parasites around age 6 months, but a proportion of weanlings and yearlings can harbour smaller burdens at age 8–10 months. Older horses have occasionally been reported with substantial ascarid burdens as well. Qualitative detection of ascarid eggs has good diagnostic value whereas an actual egg count does not correlate well with the size of the worm burden. A recent investigation documented the applicability of a transabdominal ultrasound technique for semiquantitatively monitoring ascarid burdens in foals. Control of ascarids is complicated by the limited drug classes available for treating this parasite, and by the fact that foals are often concurrently infected with strongyles. In many cases, none of the 3 available anthelmintic classes are simultaneously effective against both parasite groups, so close monitoring is required to select the most appropriate anthelmintic in each case.     

Listeria keratitis in a horse

Listeria monocytogenes is ubiquitous in the environment but is rarely reported as a cause of keratitis in animals. In this case, a mare was presented with epiphora and evidence of pain in the right eye. Listeria monocytogenes was isolated from a corneal lesion, and bacteria were also seen in the cytologic evaluation. This is the first reported case of ulcerative keratitis associated with L. monocytogenes in a horse.     

Periocular neurofibrosarcoma in a horse

A periocular neurofibrosarcoma was debulked and treated with intralesional cisplatin in a 5-year-old Thoroughbred mare. The horse presented with a 1-year history of a large slowly progressing subcutaneous mass over the right supraorbital process. The mass was surgically debulked, and intralesional cisplatin (1.0 mg/cm3) was injected in 3 doses at 2 weeks, 5 weeks, and 8 weeks postoperatively. No recurrence was noted over a 15-month follow-up period. Histopathology of the mass indicated neurofibrosarcoma.