Detection of Mycoplasma spp. and feline calicivirus in cats with ocular surface disease.

OBJECTIVE: To survey the prevalence of pathogens in shelter-housed cats with active ocular surface disease (OSD). ANIMALS STUDIED: A total of 255 shelter-housed domestic cats with evidence of active OSD. No normal, unaffected cats were sampled. PROCEDURE(S): OSD scoring was performed on cats with active OSD. Combined oropharyngeal/conjunctival swabs were submitted for rt-PCR/PCR for feline herpesvirus (FHV-1), feline calicivirus (FCV), Chlamydia spp. (CHL), Bordetella bronchiseptica (BORD), and Mycoplasma spp. (MYC). RESULTS: Pathogens were detected as follows: 76.4% (195/255) MYC, 57.6% (147/255) FHV-1, 42.7% (109/255) FCV, 26.7% (68/255) CHL, and 5.5% (14/255) BORD. Monoinfections affected 21.1% (54/255) animals, with MYC being the most common monoinfection (12.5%, 32/255), followed by FHV-1 (4.7%, 12/255), followed by CHL (2.4%, 6/255), followed by FCV (1.6%, 4/255), with no animals having a BORD monoinfection. Dual infections affected 36.4% of animals (93/255), with MYC detected in 30.1% (77/255) dual infections and FCV detected in 12.9% (33/255) dual infections. Dual infections with MYC and FCV together were detected in 9.8% (25/255) animals. Many animals (35.3%, 90/255) were found to be affected by 3 or more pathogens, and 7.1% (18/255) animals had no pathogens detected. OSD scores were not influenced by any variable assessed, including the number and type of pathogens detected. CONCLUSION: MYC, FHV-1, FCV, and CHL were commonly detected in this group of animals with OSD. Both MYC and FCV (alone or in combination with each other) were detected in multiple animals with active OSD, supporting prior evidence that either may independently act as a primary ocular surface pathogen.

Risk factors for corneal conjunctival grafting failure in dogs at four referral centers in the southern United States (203 patients): 2015-2021.

OBJECTIVE: To report risk factors associated with conjunctival graft failure in dogs at four referral specialty centers. PROCEDURES: Records of 203 dogs (229 eyes) undergoing conjunctival graft repair of ulcerative keratitis at four hospitals from 2015 to 2021 were reviewed. Success was defined as full graft integration with globe retention at the last postoperative evaluation; vision status was reported separately. Factors assessed included patient signalment, ophthalmic examination findings, surgical factors, and follow-up information. RESULTS: Conjunctival graft failure occurred in 11% (25/229) of eyes and was significantly associated with ulcer depth, with corneal perforations having increased odds of graft failure compared with descemetoceles (odds ratio [OR] = 3.22, 95% confidence interval [CI] 1.11-9.32; p = .03) and stromal ulcers (OR = 10.89 [95% CI 1.38-86.18], p = .02). Brachycephalic dogs were significantly more likely than non-brachycephalic dogs to experience graft failure (OR = 5.02 [95% CI 1.42-17.74], p < .01). Surgery on the opposite eye relative to surgeon handedness was significantly associated with an increased risk of graft failure (OR 4.28 [95% CI 1.53-11.94], p < .01). The use of 7-0 and 8-0 suture versus 9-0 (p = .03) and the use of a combined simple continuous and interrupted pattern (p = .03) were significantly associated with an increased risk of graft failure. At the last follow-up, (median 61.5 days), 87% of dogs were visual. CONCLUSIONS: Corneal perforations, surgery on the opposite eye relative to surgeon handedness, suture size and pattern, and brachycephalic conformation were significantly associated with an increased risk of graft failure in this study. These characteristics can be considered when determining prognosis for ulcerative keratitis requiring surgical intervention.

Longitudinal intraocular pressure measurements in Whooping cranes (Grus americana) and Mississippi-Sandhill cranes (Grus canadensis pulla).

OBJECTIVE: To assess intraocular pressure (IOP) development in cranes and determine the impact of age, weight, species, head position, and sex. ANIMALS STUDIED: Whooping cranes (WC) (Grus americana), and Mississippi-sandhill cranes (MSC) (Grus canadensis pulla). PROCEDURES: Chicks were manually restrained on days 1-3, 7, 21, 35, 60, 75, and 120 for routine examinations. IOP was opportunistically measured utilizing the Tonovet Plus® in D setting with the head above the heart (AH) and below the heart (BH). Values were also obtained longitudinally in adults (>120 days old) upon presentation in 1 year. RESULTS: Intraocular pressure was highly correlated with age and weight in chicks. For every kilogram gained, IOP increased 2.46 ± 0.08 mmHg in WC and 2.66 ± 0.11 mmHg in MSC. Once hatched, IOP increased 1.13 ± 0.04 mmHg in WC and 0.87 ± 0.04 mmHg in MSC every 10 days. IOP was similar to adults at 120 days of age. In adult WC, mean IOP AH was 24.0 ± 0.4 mmHg, and BH was 27.9 ± 0.4 mmHg, there was a significant difference regarding head positioning and sex, females (25.3 ± 0.4 mm Hg) had lower IOP than males (26.5 ± 0.4 mmHg). In adult MSC, mean IOP AH was 20.7 ± 0.4 mmHg, and BH was 24.6 ± 0.4 mmHg. The difference between head positioning was significant. CONCLUSIONS: This study documents the correlation between IOP and weight or age during early development in cranes, as well as the importance of head positioning.

Ocular examination findings and selected ophthalmic diagnostic tests in African green monkeys (Chlorocebus aethiops sabaeus).

OBJECTIVE: To document ocular lesions and establish ophthalmic diagnostic test reference values in a colony of African green monkeys (Chlorocebus aethiops sabaeus). ANIMALS STUDIED: Fifty one geriatric (GAGM, 19-30 years old), 10 adult (AAGM, 5-9 years old) and 10 juvenile (JAGM, <2 years old) African green monkeys housed in a single Caribbean research colony. PROCEDURES: Ocular biomicroscopy, indirect fundoscopy, Schirmer tear test (STT), rebound tonometry (TonoVet®) and corneal fluorescein staining were performed. Mixed ANCOVA tests were performed to compare STT and IOP between groups. RESULTS: Common ocular lesions in GAGM included vitreal degeneration (27/51, 51/102 eyes) and cataracts (21/51, 32/102 eyes). Vitreal degeneration was also common in AAGM (8/10, 16/20 eyes) and infrequent in JAGM (3/10, 6/20 eyes). Cataracts were not present in any JAGM or AAGM. All eyes in all three groups had perilimbal corneal pigmentation and faint lace-like anterior corneal stromal opacification. Median (range) STT values were 16.0 (18) mm/min in GAGM. Mean (SD) STT values were 14.2 (4.6) mm/min in AAGM, and 8.9 (3.4) mm/min in JAGM. Median (range) IOP values were 16.5 (27) mmHg in GAGM. Mean (SD) IOP values were 18.0 (2.8) mmHg in AAGM, and 14.1 (2.2) mmHg in JAGM. JAGM had significantly lower STT and IOP values compared to AAGM (p = .0449, .0057, respectively) and GAGM (p = .0002, .0130, respectively). CONCLUSIONS: Spontaneous ocular lesions were common in geriatric monkeys in this research colony. IOP and STT values were lower in juvenile African green monkeys relative to adult or geriatric animals.

Phylogenomic assessment of 23 equid alphaherpesvirus 1 isolates obtained from USA-based equids.

BACKGROUND: Equid alphaherpesvirus 1 (EHV-1) is a global viral pathogen of domestic equids which causes reproductive, respiratory and neurological disease. Few isolates acquired from naturally infected USA-based hosts have been fully sequenced and analyzed to date. An ORF 30 (DNA polymerase) variant (A2254G) has previously been associated with neurological disease in host animals. The purpose of this study was to perform phylogenomic analysis of EHV-1 isolates acquired from USA-based hosts and compare these isolates to previously sequenced global isolates. METHODS: EHV-1 was isolated from 23 naturally infected USA-based equids (6 different states, 15 disease outbreaks) with reproductive (22/23) or neurological disease (1/23). Following virus isolation, EHV-1 DNA was extracted for sequencing using Illumina MiSeq. Following reference-based assembly, whole viral genomes were annotated and assessed. Previously sequenced EHV-1 isolates (n = 114) obtained from global host equids were included in phylogenomic analyses. RESULTS: The overall average genomic distance was 0.0828% (SE 0.004%) for the 23 newly sequenced USA isolates and 0.0705% (SE 0.003%) when all 137 isolates were included. Clade structure was predominantly based on geographic origin. Numerous nucleotide substitutions (mean [range], 179 [114-297] synonymous and 81 [38-120] non-synonymous substitutions per isolate) were identified throughout the genome of the newly sequenced USA isolates. The previously described ORF 30 A2254G substitution (associated with neurological disease) was found in only one isolate obtained from a host with non-neurological clinical signs (reproductive disease), six additional, unique, non-synonymous ORF 30 substitutions were detected in 22/23 USA isolates. Evidence of recombination was present in most (22/23) of the newly sequenced USA isolates. CONCLUSIONS: Overall, the genomes of the 23 newly sequenced EHV-1 isolates obtained from USA-based hosts were broadly similar to global isolates. The previously described ORF 30 A2254G neurological substitution was infrequently detected in the newly sequenced USA isolates, most of which were obtained from host animals with reproductive disease. Recombination was likely to be partially responsible for genomic diversity in the newly sequenced USA isolates.

Alterations to the bovine bacterial ocular surface microbiome in the context of infectious bovine keratoconjunctivitis.

BACKGROUND: Infectious bovine keratoconjunctivitis (IBK) is a common cause of morbidity in cattle, resulting in significant economic losses. This study aimed to characterize the bovine bacterial ocular surface microbiome (OSM) through conjunctival swab samples from Normal eyes and eyes with naturally acquired, active IBK across populations of cattle using a three-part approach, including bacterial culture, relative abundance (RA, 16 S rRNA gene sequencing), and semi-quantitative random forest modeling (real-time polymerase chain reaction (RT-PCR)). RESULTS: Conjunctival swab samples were obtained from eyes individually classified as Normal (n = 376) or IBK (n = 228) based on clinical signs. Cattle unaffected by IBK and the unaffected eye in cattle with contralateral IBK were used to obtain Normal eye samples. Moraxella bovis was cultured from similar proportions of IBK (7/228, 3.07%) and Normal eyes (1/159, 0.63%) (p = 0.1481). Moraxella bovoculi was cultured more frequently (p < 0.0001) in IBK (59/228, 25.88%) than Normal (7/159, 4.40%) eyes. RA (via 16 S rRNA gene sequencing) of Actinobacteriota was significantly higher in Normal eyes (p = 0.0045). Corynebacterium variabile and Corynebacterium stationis (Actinobacteriota) were detected at significantly higher RA (p = 0.0008, p = 0.0025 respectively) in Normal eyes. Rothia nasimurium (Actinobacteriota) was detected at significantly higher RA in IBK eyes (p < 0.0001). Alpha-diversity index was not significantly different between IBK and Normal eyes (p > 0.05). Alpha-diversity indices for geographic location (p < 0.001), age (p < 0.0001), sex (p < 0.05) and breed (p < 0.01) and beta-diversity indices for geographic location (p < 0.001), disease status (p < 0.01), age (p < 0.001), sex (p < 0.001) and breed (p < 0.001) were significantly different between groups. Modeling of RT-PCR values reliably categorized the microbiome of IBK and Normal eyes; primers for Moraxella bovoculi, Moraxella bovis, and Staphylococcus spp. were consistently the most significant canonical variables in these models. CONCLUSIONS: The results provide further evidence that multiple elements of the bovine bacterial OSM are altered in the context of IBK, indicating the involvement of a variety of bacteria in addition to Moraxella bovis, including Moraxella bovoculi and R. nasimurium, among others. Actinobacteriota RA is altered in IBK, providing possible opportunities for novel therapeutic interventions. While RT-PCR modeling provided limited further support for the involvement of Moraxella bovis in IBK, this was not overtly reflected in culture or RA results. Results also highlight the influence of geographic location and breed type (dairy or beef) on the bovine bacterial OSM. RT-PCR modeling reliably categorized samples as IBK or Normal.

Relationship between the bacterial ocular surface microbiota and outcomes for cats with feline herpesvirus type 1 ocular surface disease.

OBJECTIVE: Feline herpesvirus 1 (FHV-1) causes ocular surface disease in domestic cats. The purpose of this study was to assess the relationship between bacterial ocular surface microbiota and outcomes for cats with FHV-1 ocular surface disease. ANIMALS STUDIED: Twenty-two shelter-housed cats with confirmed FHV-1 ocular surface disease. PROCEDURES: Animals were grouped according to FHV-1 shedding and ocular clinical scores following intervention: worsened outcome (WorOut, n = 11) or improved outcome (ImpOut, n = 11). Scoring and conjunctival sampling were completed on Days 1 and 8 of twice daily antiviral treatment. Bacterial DNA was extracted and submitted for 16S rRNA gene sequencing. Real-time polymerase chain reaction was performed for selected bacterial species. Overall DNA concentration between groups was assessed. RESULTS: Bacterial microbiota relative abundance composition was significantly different between ImpOut and WorOut groups (weighted UniFrac p = .006). Alpha diversity was significantly higher in the ImpOut group compared with the WorOut group (Shannon p = .042, Simpson's p = .022, Pielou's p = .037). Differences in the relative abundance of various phyla and species were detected between groups. Total DNA concentration was higher in the WorOut group compared with the ImpOut group (p = .04). Feline GAPDH (p = .001) and Bilophila wadsworthia (p = .024) copy number was significantly higher in the ImpOut group compared with the WorOut group. CONCLUSIONS: The results highlight the important relationship between the bacterial ocular surface microbiota and FHV-1 infection outcomes in cats treated with antiviral medications. Low bacterial species diversity, higher overall DNA (presumed predominantly bacterial) load, and certain bacterial phyla/species were associated with poor outcomes for cats with FHV-1 ocular disease.

Validation of a novel rebound tonometer (Tono-Vera® Vet) in normal ex vivo rabbit eyes.

OBJECTIVE: The purpose of this study was to validate the use of the Reichert Tono-Vera® Vet tonometer rabbit setting in normal ex vivo rabbit eyes and to compare the rabbit setting to the dog, cat, and horse settings of this tonometer. PROCEDURE: Six freshly enucleated normal rabbit eyes were cannulated and connected to a fluid reservoir and physiologic monitor. Triplicate measurements were obtained with the four available settings: dog, cat, horse, and rabbit at various intraocular pressures (IOP) ranging from 5 to 80 mmHg. Bland-Altman analysis was utilized to determine bias and 95% limits of agreement for each setting. RESULTS: Linear regression equations for the dog, horse, cat, and rabbit settings were y = 0.8101x + 2.5058, y = 0.7594x - 3.4673, y = 0.6635x + 0.3021, and y = 0.8935x + 1.3295, respectively. All settings demonstrated strong positive linear trends (dog r2 = 0.9644, horse r2 = 0.9456, cat r2 = 0.9309, and rabbit r2 = 0.9558). Bland-Altman plots revealed that the average bias and 95% limits of agreement (mmHg) were -4.73, -12.65, -12.86 and -2.73 and (-15.31, 5.86), (-29.03, 3.74), (-25.67, -0.05), and (-12.21, 6.76) for the dog, horse, cat, and rabbit settings, respectively. CONCLUSION: The Tono-Vera® Vet rabbit setting provided the most accurate and precise measurements compared with the other settings, but slightly underestimated actual IOP, especially as IOP was increased. This tonometer, using the rabbit setting, is likely to be appropriate for the estimation of IOP in rabbits with the appropriate correction formula applied.

Surveillance for feline herpesvirus type 1 mutation and development of resistance in cats treated with antiviral medications.

Feline herpesvirus type 1 (FHV-1) commonly causes ocular surface disease in cats and is treated with antiviral medications targeting viral DNA polymerase (UL30/42). Herein, we describe a method to assess the FHV-1 genome for mutation development and to assess the functional impact of mutations, if present. Fourteen shelter-housed domestic cats with FHV-1 ocular surface disease were assigned to one of four treatment groups: placebo (n = 3), cidofovir 0.5% ophthalmic solution (n = 3), famciclovir oral solution (n = 5), or ganciclovir 0.15% ophthalmic solution (n = 3). Swabs were collected before (day 1) and after (day 8) 1 week of twice-daily treatments to isolate viable FHV-1. Viral DNA was extracted for sequencing using Illumina MiSeq with subsequent genomic variant detection between paired day 1 and day 8 isolates. Plaque reduction assay was performed on paired isolates demonstrating non-synonymous variants. A total of 171 synonymous and 3 non-synonymous variants were identified in day 8 isolates. No variants were detected in viral UL23, UL30, or UL42 genes. Variant totals were not statistically different in animals receiving antiviral or placebo (p = 0.4997). A day 8 isolate from each antiviral treatment group contained a single non-synonymous variant in ICP4 (transcriptional regulator). These 3 isolates demonstrated no evidence of functional antiviral resistance when IC50 was assessed. Most (10/14 pairs) day 1 and 8 viral isolate pairs from the same host animal were near-identical. While functional variants were not detected in this small sample, these techniques can be replicated to assess FHV-1 isolates suspected of having developed resistance to antiviral medications.

Relative and Quantitative Characterization of the Bovine Bacterial Ocular Surface Microbiome in the Context of Suspected Ocular Squamous Cell Carcinoma.

The ocular surface microbiome is altered in certain disease states. The aim of this study was to characterize the bovine bacterial ocular surface microbiome (BBOSM) in the context of ocular squamous cell carcinoma (OSCC). The conjunctiva of normal (n = 28) and OSCC (n = 10) eyes of cows aged 2 to 13 years from two farms in Louisiana and Wyoming were sampled using individual sterile swabs. DNA extraction followed by 16S ribosomal ribonucleic acid (rRNA) gene sequencing and real-time polymerase chain reaction (RT-PCR) were performed to, respectively, assess the relative and absolute BBOSM. Discriminant analysis (DA) was performed using RT-PCR data, and relative abundance analysis was performed using 16S rRNA gene sequencing data. The 11 most abundant phyla in both normal and OSCC-affected cows were identified using 16S rRNA gene sequencing analysis. The relative abundance of Euryarchaeota was found to be significantly lower (p = 0.0372) in OSCC eyes compared to normal eyes. Relative abundance differences within and between geographic locations were also identified. Quadratic DA categorized samples as OSCC or normal with 100% sensitivity and 83.3-100% specificity. Relative abundance analysis identified relative BBOSM phylum alterations in OSCC. Quadratic DA can be used to accurately categorize BBOSM from normal and OSCC ocular surface samples.

Successful Surgical Removal of the Crystalline Lenses in a Black-Necked Swan (Cygnus melancoryphus).

A captive-bred, adult, male, black-necked swan (Cygnus melancoryphus) was presented for evaluation of apparent vision loss due to cataract formation of an unknown duration. The animal was having difficulty navigating its enclosure, and lenticular opacities had been previously noted in both eyes. On examination, bilateral hypermature cataracts were diagnosed. Following preoperative diagnostic testing, surgical removal of the crystalline lenses in both eyes was performed using minor modifications of standard techniques. Follow-up examination and behavioral observation at 60 days postsurgery indicated that vision had been successfully restored without complications. We conclude that successful surgical removal of cataracts is possible in this species using modifications of standard techniques.

Efficacy of perioperative 2% dorzolamide ophthalmic solution for reduction of postoperative ocular hypertension in dogs following routine phacoemulsification surgery: A prospective clinical trial.

OBJECTIVE: To evaluate the efficacy of 2% dorzolamide ophthalmic solution for reduction of postoperative ocular hypertension (POH) following routine phacoemulsification surgery in dogs. ANIMALS STUDIED: Thirty one dogs (53 eyes) with naturally occurring cataracts undergoing routine phacoemulsification surgery. PROCEDURE(S): A prospective, double-masked, randomized, placebo-controlled study design was utilized. Dogs received 2% dorzolamide ophthalmic solution or saline 1 h prior to surgery then three times daily for 21 days postoperatively in the operated eye(s). Intraocular pressure (IOP) was recorded 1 h prior to surgery and 3 h, 7 h, 22 h, 1 week and 3 weeks postoperatively. Statistical analyses were performed using chi-squared and Mann-Whitney U test with a significance level of p < .05. RESULTS: Postoperative ocular hypertension (IOP ≥25 mmHg, <24 h after surgery) occurred in 28/53 (52.8%) eyes. There was significant reduction in the incidence of POH for eyes receiving dorzolamide (10/26 (38.4%) eyes) versus eyes receiving placebo (18/27 (66.7%) eyes) (p = .0384). Animals were followed for a median of 163 days after surgery. Thirty-seven (37/53 (69.8%)) eyes were visual at final examination and 3/53 (5.7%) globes were enucleated postoperatively. At last follow-up, there was no difference in visual status (p = .9280), need for topical IOP lowering medication (p = .8319) or incidence of glaucoma (p = .5880) based on treatment group. CONCLUSIONS: Perioperative administration of topical 2% dorzolamide reduced the incidence of POH after phacoemulsification in the dogs studied. However, this was not associated with differences in visual outcome, incidence of glaucoma or need for IOP-lowering medications.

A review of evidence-based management of infectious ocular surface disease in shelter-housed domestic cats.

Infectious ocular surface disease (IOSD) is a common problem in shelter-housed domestic cats and has a widespread negative impact on animal welfare. While the common etiological agents are well-described, addressing IOSD in large groups of animals presents a management challenge to the clinician and logistical challenges to shelter employees. Treatments, diagnostics, and prevention strategies that are effective in privately owned or experimental animals may be impractical or ineffective in the shelter environment. This review article focuses on the relative prevalence of etiological agents in feline IOSD, practical diagnostic testing protocols, prevention strategies, and treatment of IOSD in shelter-housed cats. Discrepancies between experimental laboratory-based studies and clinical trials assessing therapeutics for treatment of feline herpes virus are highlighted. Further high-quality clinical trials are necessary to determine optimal preventative and therapeutic protocols for IOSD in shelter-housed cats.

Evaluation of compounded cidofovir, famciclovir, and ganciclovir for the treatment of feline herpesvirus ocular surface disease in shelter-housed cats.

OBJECTIVE: To assess the efficacy of compounded cidofovir, famciclovir, and ganciclovir for the treatment of feline herpesvirus type 1 (FHV-1) ocular surface disease. ANIMALS STUDIED: 132 shelter-housed cats qPCR positive for FHV-1. PROCEDURES: A masked placebo-controlled study design was utilized. Animals were enrolled in one of four treatment groups: topical ocular placebo + oral placebo (n = 32), compounded cidofovir 0.5% ophthalmic solution + oral placebo (n = 32), compounded famciclovir oral solution (90 mg/kg) + topical ocular placebo (n = 32), and compounded ganciclovir 0.15% ophthalmic solution + oral placebo (n = 36). Cats were treated with each medication twice daily for 7 days and were evaluated on Day 1 and Day 8 using an ocular scoring system, body weight, and qPCR for FHV-1 viral load. RESULTS: Cidofovir significantly decreased viral load from Day 1 to Day 8 compared with placebo (p = .024). Neither famciclovir nor ganciclovir decreased viral load compared with placebo (p = .14, p = .41). There was no significant improvement of ocular scores for any drug group compared with placebo (p = .62). In all groups, 65%-75% of cats improved from Day 1 to Day 8. Juvenile cats had a significant increase in weight gain compared with placebo for cidofovir (p = .025) and ganciclovir (p = .023). All corneal ulcers in placebo animals failed to heal whereas 77% of ulcers in antiviral group animals healed. CONCLUSIONS: Topical ophthalmic cidofovir significantly decreased ocular FHV-1 viral shedding and increased weight gain in juvenile cats. Ganciclovir increased weight gain in juvenile cats. Compounded famciclovir demonstrated limited efficacy for the treatment of FHV-1 ocular surface disease in shelter-housed cats.

Hyphema and secondary glaucoma as a presenting complaint in a dog with chronic lymphocytic leukemia.

A 5-year-old Pomeranian was diagnosed with anterior uveitis, hyphema, and secondary glaucoma OD. Concurrent retinal hemorrhage, perivascular sheathing, and papilledema were identified OS. Work-up identified small cell lymphocytosis (>900 × 109/L), anemia, and thrombocytopenia. The patient was diagnosed with B-cell chronic lymphocytic leukemia as a cause of the ocular findings.

The effect of topical ophthalmic proparacaine, fluorescein, and tropicamide on subsequent bacterial cultures in healthy dogs.

OBJECTIVE: To determine whether tropicamide, fluorescein, and proparacaine applied topically before sample collection affect the quantity or species of bacteria isolated via aerobic culture. ANIMALS STUDIED: 12 female adult research beagle cross-breed dogs. PROCEDURES: A conjunctival swab was taken before and after the sequential application of proparacaine, tropicamide, and fluorescein to the same eye (P/T/F) with a five-minute gap between medications. Paired swabs were submitted for aerobic culture. Bacterial enumeration was performed using the spread plate method. Following a one-week washout period, the procedure was repeated using balanced salt solution (BSS). Following a second one-week washout period, the experiment was repeated using ofloxacin 0.3% solution. Colony counts were compared using one-way ANOVA and Tukey post hoc comparison. Bacterial species reduction was compared using a Friedman rank test and Dunn's method. RESULTS: The bacterial colony count for P/T/F and BSS was significantly higher than the ofloxacin group (p = 0.0052, p = 0.0022). There was no significant difference for colony counts between P/T/F and BSS (p = 0.9295). The most frequently isolated bacteria included: Psychrobacter spp., Staphylococcus spp., Corynebacterium spp., and Streptococcus spp. The bacterial species reduction for P/T/F and BSS was significantly lower than for ofloxacin (p < 0.0001, p = 0.0160). There was no significant difference for species reduction between P/T/F and BSS (p = 0.3749). CONCLUSIONS: The application of proparacaine, tropicamide, and fluorescein did not significantly decrease the amount or species of bacteria isolated from the conjunctiva in this canine population. The application of these solutions prior to ocular swab collection in healthy dogs is unlikely to affect subsequent culture results.

Intramuscular Vaccination With the HSV-1(VC2) Live-Attenuated Vaccine Strain Confers Protection Against Viral Ocular Immunopathogenesis Associated With γδT Cell Intracorneal Infiltration.

Herpes simplex virus type-1 (HSV-1) ocular infection is one of the leading causes of infectious blindness in developed countries. The resultant herpetic keratitis (HK) is caused by an exacerbated reaction of the adaptive immune response that persists beyond virus clearance causing substantial damage to the cornea. Intramuscular immunization of mice with the HSV-1(VC2) live-attenuated vaccine strain has been shown to protect mice against lethal ocular challenge. Herein, we show that following ocular challenge, VC2 vaccinated animals control ocular immunopathogenesis in the absence of neutralizing antibodies on ocular surfaces. Ocular protection is associated with enhanced intracorneal infiltration of γδ T cells compared to mock-vaccinated animals. The observed γδ T cellular infiltration was inversely proportional to the infiltration of neutrophils, the latter associated with exacerbated tissue damage. Inhibition of T cell migration into ocular tissues by the S1P receptors agonist FTY720 produced significant ocular disease in vaccinated mice and marked increase in neutrophil infiltration. These results indicate that ocular challenge of mice immunized with the VC2 vaccine induce a unique ocular mucosal response that leads into the infiltration of γδ T cells resulting in the amelioration of infection-associated immunopathogenesis.

Full Viral Genome Sequencing and Phylogenomic Analysis of Feline Herpesvirus Type 1 (FHV-1) in Cheetahs (Acinonyx jubatus).

Feline herpesvirus type 1 (FHV-1) is endemic in captive cheetahs and sporadically causes devastating disease. Modified live vaccines (MLV), intended for use in domestic cats, are used in some captive cheetah populations and have been anecdotally linked to disease in certain subpopulations. Ten FHV-1 isolates from ten captive cheetahs and one isolate from an MLV used to inoculate four of the host animals were analyzed. Viral DNA was extracted for full-genome sequencing by Illumina MiSeq with viral genomes then used for phylogenomic and recombinational analyses. The FHV-1 shed by vaccinated cheetahs were almost identical to the MLV, with few variants among viral genomes. Eight cheetah FHV-1 isolates and the MLV were grouped in a clade along with FHV-1 isolates from domestic cats in the USA. The remaining two cheetah FHV-1 isolates (unknown host vaccine status) were not associated with a clade. The likely ancestral origin of these two isolates involves recombination events between Australian domestic cat and cheetah FHV-1 isolates. Collectively, these data suggest that the MLV is capable of causing clinical disease and viral shedding in some cheetahs and represents evidence of interspecies transmission of virus between domestic and wild cats.

Assessment of Cidofovir for Treatment of Ocular Bovine Herpesvirus-1 Infection in Cattle Using an Ex-Vivo Model.

Bovine herpesvirus-1 (BoHV-1) infection contributes to keratoconjunctivitis, respiratory disease, and reproductive losses in cattle. The objective of this study was to determine the most appropriate ophthalmic antiviral agent for BoHV-1 inhibition using in-vitro culture and novel ex-vivo bovine corneal modeling. Half-maximal inhibitory concentrations of BoHV-1 were determined for cidofovir, ganciclovir, idoxuridine, and trifluridine via in-vitro plaque reduction assays. In-vitro cytotoxicity was compared amongst these compounds via luciferase assays. Trifluridine and cidofovir were the most potent BoHV-1 inhibitors in vitro, while trifluridine and idoxuridine were the most cytotoxic agents. Therefore, cidofovir was the most potent non-cytotoxic agent and was employed in the ex-vivo corneal assay. Corneoscleral rings (n = 36) from fresh cadaver bovine globes were harvested and equally divided into an uninfected, untreated control group; a BoHV-1-infected, untreated group; and a BoHV-1-infected, cidofovir-treated group. Virus isolation for BoHV-1 titers was performed from corneal tissue and liquid media. Histologic measurements of corneal thickness, epithelial cell density, and tissue organization were compared between groups. Substantial BoHV-1 replication was observed in infected, untreated corneas, but BoHV-1 titer was significantly reduced in cidofovir-treated (1.69 ± 0.08 × 103 PFU/mL) versus untreated (8.25 ± 0.25 × 105 PFU/mL, p < 0.0001) tissues by day 2 of culture. No significant differences in histologic criteria were observed between groups. In conclusion, cidofovir warrants further investigation as treatment for BoHV-1 keratoconjunctivitis, with future studies needed to assess in-vivo tolerability and efficacy.

Ophthalmic Evaluation of Raptors Suffering From Ocular Trauma.

Ocular problems are often associated with traumatic injury in raptors. A comprehensive evaluation, including a complete ophthalmic examination, is vital in determining the patient's overall health and suitability for release. Steps for conducting ocular examination and diagnostic testing in raptors is discussed. Additionally, common clinical findings after trauma, as well as the mechanisms by which ocular injury occurs, are outlined. An overview of medical treatments recommended for commonly diagnosed ocular diseases and the utility of ancillary diagnostic procedures is also presented.