In vivo confocal microscopic features of naturally acquired canine herpesvirus-1 and feline herpesvirus-1 dendritic and punctate ulcerative keratitis.

OBJECTIVE: To describe the in vivo confocal microscopy (IVCM) features of the corneal epithelium and stroma in dogs and cats with herpetic dendritic ulcerative keratitis. ANIMALS: 6 client-owned dogs and 10 client-owned cats with herpetic dendritic ulcerative keratitis (affected group) and 10 dogs and 10 cats from specific-pathogen-free laboratory colonies (nonaffected group). PROCEDURES: After complete ophthalmic examination, IVCM corneal examination was performed on the clinically diseased eyes of animals in the affected group and on both eyes of animals in the nonaffected group. Results by species were compared between groups. RESULTS: In the affected group, all 6 dogs had unilateral ocular lesions (total, 6 eyes examined), whereas 7 cats had unilateral lesions and 3 cats had bilateral lesions (total, 13 eyes examined). For the nonaffected group, 20 cat eyes and 20 dog eyes were examined. Corneal epithelial morphological abnormalities were identified in all examined eyes of animals in the affected group and in no examined eyes of the nonaffected group. Hyperreflective punctate opacities and inflammatory cells were present in all epithelial layers in examined eyes of affected animals but were absent in nonaffected animals. Similarly, Langerhans cells and anterior stromal dendritic cells were identified in corneas of eyes examined for animals in the affected group but not in any eye of animals in the nonaffected group. Stromal changes were less consistent in the affected group, but absent in the nonaffected group. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that herpetic dendritic ulcerative keratitis in dogs and cats is associated with microanatomic corneal abnormalities that can be detected by IVCM.

Intensive ocular sampling for the detection of subclinical canine herpesvirus-1 shedding in dogs with experimentally-induced latent infection.

Latent canine herpesvirus-1 (CaHV-1) infections are common in domestic dogs, but viral shedding patterns in dogs are poorly understood. Previous research failed to detect spontaneous subclinical ocular CaHV-1 shedding in dogs following ocular infection, a situation that is fundamentally distinct from many of the alphaherpesviruses closely related to CaHV-1. One possible explanation for this finding is that the sampling interval in the prior studies evaluating ocular shedding patterns was too infrequent to detect rapidly cleared, brief ocular viral shedding episodes. To evaluate for this potential viral shedding scenario, 10 laboratory beagles recovered from experimental primary ocular CaHV-1 infection and with latent CaHV-1infection were intensively monitored for viral reactivation and shedding for 28 days. Clinical ophthalmic examinations were performed daily. Ocular swab samples were collected for CaHV-1 polymerase chain reaction 3 times daily and CaHV-1 virus neutralizing antibody assays were evaluated at 2-week intervals. No abnormalities suggestive of recurrent CaHV-1 ocular disease were observed during clinical ophthalmic examination in the dogs during the study. Ocular CaHV-1 shedding was not detected by polymerase chain reaction and CaHV-1 virus neutralizing antibody titers remained stable in all dogs for the study duration. In the present study utilizing frequent multiple daily sample collections, no evidence of subclinical ocular CaHV-1 shedding was detected in mature dogs with experimentally-induced latent CaHV-1 infection.

Analgesic effect of topical and subconjunctival morphine in dogs after phacoemulsification: A pilot study.

OBJECTIVE: To determine the efficacy of a single treatment of topical and subconjunctival 0.1% preservative-free morphine sulfate (PFMS) in providing analgesia following phacoemulsification in dogs. ANIMALS STUDIED: Ten diabetic and ten non-diabetic client-owned dogs treated with bilateral phacoemulsification. PROCEDURES: A prospective, randomized, masked, negative-controlled clinical trial was performed. All dogs received topical (0.2 mL) and subconjunctival (0.1 mL) 0.1% PFMS in one eye following phacoemulsification. The other eye received an equal volume and mode of administration of balanced salt solution (BSS). Ophthalmic examination, blinking rates, tearing, conjunctival hyperemia, aqueous flare, and central corneal esthesiometry (CCE) were evaluated in all eyes 1 day prior to surgery and at 4, 24, and 48 hours after surgery. Complete physical examination, ocular ultrasound, electroretinogram, hemogram, and serum biochemistry panel were performed in all dogs prior to phacoemulsification. All dogs received the standard of care treatment before and after surgery, including uniform anesthetic protocol. RESULTS: Baseline ophthalmic exams were unremarkable, except for the presence of cataracts, in all dogs. The mean CCE (±SD) at 4 hours post-operatively was 1.76 ± 1.27 g/mm2 and 1.85 ± 1.5 g/mm2 for the negative control and PFMS groups, respectively. There were no statistical differences in blepharospasm, conjunctival hyperemia, tearing, aqueous flare, blinking rates, CCE, or intraocular pressure (IOP) between the treatment groups for any of the time points for the non-diabetic and diabetic dogs, or for all dogs combined (P > .05). CONCLUSIONS: Topical and subconjunctival 0.1% PFMS did not affect the evaluated parameters after phacoemulsification in the study dogs at the timepoints assessed.

Effects of orally administered raltegravir in cats with experimentally induced ocular and respiratory feline herpesvirus-1 infection.

OBJECTIVE: To determine the effects of orally administered raltegravir in cats with experimentally induced ocular and respiratory feline herpesvirus-1 (FHV-1) infection. ANIMALS: 14 healthy 6-month-old unvaccinated specific pathogen-free cats. PROCEDURES: On day 0, all cats were experimentally inoculated by topical application of 0.1 mL of a solution containing 106 plaque-forming units of FHV-1 strain FH2CS to the inferior conjunctival fornix of each eye. Cats were randomly assigned to receive either raltegravir (80 mg; n = 7) or lactose (250 mg; vehicle; 7), PO, every 12 hours for 14 days beginning on day 1. Cats were assigned clinical ocular and respiratory disease scores every other day from days 0 to 30. Conjunctival swab specimens were collected for detection of FHV-1 by virus isolation and real-time PCR assay at 3-day intervals from days 0 to 30. Confocal microscopy was performed on days 0 and 10 to assess corneal epithelial leukocyte infiltration. The assessed variables and duration of FHV-1 shedding were compared between the 2 treatment groups. RESULTS: Cats in both groups developed moderate to severe conjunctivitis and ulcerative keratitis characteristic of FHV-1 infection. Median duration of FHV-1 shedding was shorter and signs of ocular and respiratory disease were less severe for raltegravir-treated cats than for vehicle-treated cats. However, the mean conjunctival FHV-1 titer and corneal epithelial leukocyte count did not differ between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested orally administered raltegravir might be effective for alleviation of ocular and respiratory signs of FHV-1 infection in cats. (Am J Vet Res 2019;80:490-497).

Incidence and characteristics of acute-onset postoperative bacterial and sterile endophthalmitis in dogs following elective phacoemulsification: 1,447 cases (1995-2015).

OBJECTIVE To characterize and determine the incidence of acute-onset (ie, developing ≤ 6 weeks after surgery) postoperative infectious and sterile endophthalmitis in dogs following elective cataract surgery. DESIGN Retrospective case series. ANIMALS 2,630 eyes of 1,447 dogs that underwent elective unilateral or bilateral cataract surgery by phacoemulsification at Cornell University from 1995 through 2015. PROCEDURES Medical records were reviewed to collect and summarize data regarding dog signalment, clinical findings, diagnostic test results, surgery characteristics, eye or eyes affected, concurrent major systemic diseases, treatments, and clinical outcome. RESULTS Infectious endophthalmitis developed in 4 eyes of 4 dogs during the follow-up period, representing 0.15% of eyes and 0.28% of dogs that underwent surgery. Unilateral sterile endophthalmitis developed in 3 (0.11%) eyes of 3 (0.21%) dogs. All cases of infectious endophthalmitis were unilateral and in pseudophakic eyes and followed bilateral cataract surgeries. Clinical signs consistent with infectious endophthalmitis developed a median of 18 days after surgery and included marked and progressive hypopyon; Staphylococcus or Streptococcus spp were recovered from aqueous and vitreous humor samples. All eyes with infectious endophthalmitis responded poorly to medical treatment and were enucleated. In 2 eyes with infectious endophthalmitis, corneal incision nonunion with epithelial downgrowth was identified histologically and postulated as the route of bacterial entry into the globe. CONCLUSIONS AND CLINICAL RELEVANCE Bacterial endophthalmitis following elective phacoemulsification was uncommon in the dogs of this study. Introduction of bacteria into the eye may occur during surgery or in the postoperative period from corneal incisions that fail to heal normally.

Evaluation of topical ophthalmic ganciclovir gel for the treatment of dogs with experimentally induced ocular canine herpesvirus-1 infection.

OBJECTIVE To determine the in vitro half maximal effective concentration (EC50) of ganciclovir for canine herpesvirus-1 (CHV-1) and to evaluate the efficacy of ganciclovir ophthalmic gel in dogs with experimentally induced ocular CHV-1 infection. ANIMALS 10 specific pathogen-free adult Beagles. PROCEDURES Cytotoxicity and EC50 of ganciclovir for CHV-1 were determined during in vitro experiments. During an in vivo experiment, dogs with experimentally induced ocular CHV-1 infections received 1 drop of 0.15% ganciclovir (ganciclovir group; n = 5) or artificial tear (control group; 5) ophthalmic gel in both eyes 5 times daily for 7 days, then 3 times daily for 7 days. For each dog, ophthalmic and confocal microscopic examinations were performed at predetermined times to determine severity of ocular disease and inflammation. Conjunctival swab specimens were collected at predetermined times for PCR assay analysis to determine CHV-1 shedding. RESULTS No in vitro cytotoxic effects were observed for ganciclovir concentrations ≤ 500µM. The EC50 of ganciclovir for CHV-1 was 37.7µM. No adverse effects associated with ganciclovir were observed during the in vivo experiment. Mean ocular disease and inflammation scores for the ganciclovir group were significantly lower than those for the control group. Mean duration of CHV-1 shedding for the ganciclovir group (0.4 days) was significantly shorter than that for the control group (6.2 days). CONCLUSIONS AND CLINICAL RELEVANCE Topical administration of 0.15% ganciclovir ophthalmic gel was well tolerated and effective in decreasing clinical disease scores, ocular tissue inflammation, and duration of viral shedding in dogs with experimentally induced ocular CHV-1 infection.

Diamond burr debridement vs. grid keratotomy in canine SCCED with scanning electron microscopy diamond burr tip analysis.

OBJECTIVES: (i) Compare the outcome of canine SCCED treated with grid keratotomy (GK) or diamond burr debridement (DBD); (ii) Serially evaluate morphologic and elemental composition changes to diamond burr tips. ANIMALS STUDIED: A total of 91 eyes of 88 canine SCCED patients treated at the University of Missouri (2005-2015); 75 fresh cadaver porcine globes. PROCEDURES: (i) Medical records were reviewed retrospectively. Data were analyzed for age, sex, breed, procedure performed, eye(s) on which the procedure was performed, time to healing after a single surgical procedure, performance of a second surgical procedure, contact lens placement, and postprocedural complications. (ii) Three naïve 3.5-mm medium grit burr tips were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). DBD was performed for 120 s on 8-mm porcine corneal stroma using the Algerbrush® . Manufacturer-recommended cleaning protocols were followed. SEM and EDS analyses were performed in triplicate after 10, 25, and 50 DBD, cleaning, and sterilization cycles. RESULTS: There was no statistically significant difference in healing between DBD and GK groups (P = 0.50). No diamond particle damage after 10, 25, or 50 DBDs was detected. SEM secondary electron imaging and backscatter electron imaging after repeated uses demonstrated a build-up of contamination composed of carbon, sulfur, and calcium on burr tips. CONCLUSIONS: Both DBD and GK are effective treatment options for canine SCCED. Although complications are rare after DBD, build-up of contaminants may be a contributing factor. Additional cleaning and sterilization protocols are being investigated.

Effects of topical ocular application of 1% trifluridine ophthalmic solution in dogs with experimentally induced recurrent ocular canine herpesvirus-1 infection.

OBJECTIVE To determine the effects of topical ocular application of 1% trifluridine ophthalmic solution in dogs with experimentally induced recurrent ocular canine herpesvirus-1 (CHV-1) infection. ANIMALS 10 specific pathogen-free Beagles. PROCEDURES 12 months prior to the beginning of the randomized, masked, placebo-controlled 30-day trial, latent ocular CHV-1 infection was experimentally induced in each dog by topical ocular inoculation of both eyes with a field strain of CHV-1. Recurrent ocular CHV-1 infection was induced by oral administration of prednisolone for 7 days (starting day 1). Starting on the fourth day of prednisolone administration, each dog received 1% trifluridine solution or artificial tears (placebo) topically in both eyes 6 times daily for 2 days and then 4 times daily for 12 days. Ophthalmic examinations were performed every 2 days, and ocular disease scores were calculated. Ocular samples for CHV-1 PCR assays and blood samples for clinicopathologic analyses and assessment of CHV-1 serum neutralization antibody titers were collected at predetermined intervals. RESULTS Conjunctivitis was clinically detected in all dogs by day 4. Compared with dogs receiving placebo, mean and total clinical ocular disease scores were significantly lower and median CHV-1 shedding duration was significantly shorter for the trifluridine-treated dogs. Both groups had increasing CHV-1 serum neutralization antibody titers over time, but no significant differences between groups were detected. Clinicopathologic findings were unremarkable throughout the study. CONCLUSIONS AND CLINICAL RELEVANCE Topical ocular application of 1% trifluridine ophthalmic solution was well tolerated and effective at reducing disease scores and viral shedding duration in dogs with experimentally induced ocular CHV-1 infection, but may require frequent administration.

In Vitro and In Vivo Evaluation of Cidofovir as a Topical Ophthalmic Antiviral for Ocular Canine Herpesvirus-1 Infections in Dogs.

PURPOSE: The effects of cidofovir were investigated against canine herpesvirus-1 (CHV-1) in vitro and in dogs with experimentally induced recurrent ocular CHV-1 infection, a host-adapted pathogen animal model of ocular herpes simplex virus-1 (HSV-1) infection. METHODS: The cidofovir EC50 was determined for CHV-1 and HSV-1. A randomized, masked vehicle-controlled trial was performed using beagles with experimentally induced recurrent ocular CHV-1 infection. Dogs received 1 drop of 0.5% cidofovir solution or 0.9% sodium chloride solution (vehicle) in both eyes 2 times daily for 14 days. Dogs were monitored at intervals for 30 days by a clinical ophthalmic examination, in vivo confocal microscopy of the cornea and conjunctiva, ocular sample CHV-1 polymerase chain reaction assay, hemogram, and serum biochemistry panel. Clinical ocular disease scores were calculated and infiltrating leukocytes detected by in vivo confocal microscopy quantified. RESULTS: Cidofovir displayed similar in vitro antiviral activity against CHV-1 and HSV-1. Clinical ocular disease scores were significantly higher in the cidofovir group compared to the vehicle group. Marked conjunctival pigmentation and blepharitis were also detected in the cidofovir group, but not the vehicle group. Conjunctival and corneal leukocyte infiltration scores determined by in vivo confocal microscopy were significantly higher in the cidofovir group. Dogs administered cidofovir had significantly reduced durations of ocular viral shedding compared to the vehicle group. Hemogram and serum biochemistry panel values were unremarkable. CONCLUSIONS: Twice-daily application of topical 0.5% cidofovir ophthalmic solution reduced the duration of ocular viral shedding in dogs with experimentally induced recurrent ocular CHV-1 infection, but was associated with local ocular toxicity.