Ophthalmomyiasis interna anterior in a dog: keratotomy and extraction of a Cuterebra sp. larva.

A 1-year-old female spayed mixed-breed dog was presented for evaluation of acute onset of lethargy and blepharospasm OD. Slit-lamp biomicroscopy revealed a segmented larva embedded in the inferonasal iris. Moderate anterior uveitis was present. After pharmacologic dilation, mild vitreal hemorrhage and chorioretinal migration tracks were identified. The dog was treated empirically for uveitis for 5 days, after which a keratotomy and larval foreign body extraction was performed. The dog recovered uneventfully from intraocular surgery and remained visual and comfortable. Parasite evaluation confirmed the larva to be a Cuterebra sp. To the authors' knowledge, this is the first report of canine ophthalmomyiasis interna anterior, and the first report of successful surgical removal from the anterior segment in a dog with preservation of vision.

Brucella canis endophthalmitis in 3 dogs: clinical features, diagnosis, and treatment.

OBJECTIVE: To describe historical, clinical and diagnostic features of dogs with Brucella canis endophthalmitis and the response to medical therapy. ANIMALS STUDIED: Three dogs with naturally acquired B. canis endophthalmitis. PROCEDURE: Dogs were treated symptomatically with topical ophthalmic anti-inflammatories and a novel antimicrobial protocol that included doxycycline, enrofloxacin, rifampin and streptomycin. RESULTS: All dogs presented with chronic or recurrent uveitis in the absence of overt systemic disease. Clinical ophthalmologic abnormalities were unilateral in each dog and included mild-to-moderate anterior uveitis, iris hyperpigmentation, marked vitreal infiltrates, and multifocal chorioretinitis. Dogs were diagnosed with canine brucellosis serologically and by blood culture (n = 2 dogs) or polymerase chain reaction of aqueous humor and blood (n = 1 dog). Active ocular inflammation resolved in all dogs during treatment, with preservation of vision in 2 dogs. Following treatment, B. canis could not be cultured from blood samples and serological values declined with seronegativity achieved in all dogs after a median of 96 weeks (range: 36-112 weeks) of therapy. CONCLUSIONS: Brucella canis infection should be included in the differential diagnosis for dogs with intraocular inflammation, regardless of previous history or neuter status. This is the first report of apparently successful medical therapy of canine brucellosis with ocular involvement.

Orbital abscess bacterial isolates and in vitro antimicrobial susceptibility patterns in dogs and cats.

OBJECTIVE: To determine bacterial populations, in vitro antimicrobial susceptibility patterns, and sources of microorganisms for dogs and cats with orbital abscess. ANIMALS STUDIED: In total, 34 dogs and 7 cats with orbital abscess participated in the study. PROCEDURE: Medical records of dogs and cats with a clinical diagnosis of orbital abscess, confirmed by cytologic or histopathologic evaluation of orbital specimens, were reviewed from the years 1990 to 2007. Animal signalment, presumptive source of microorganisms and mechanism of orbital introduction, bacterial isolates, and aerobic bacterial in vitro antimicrobial susceptibility test results were recorded. Percentages of susceptible aerobic bacterial isolates were compared among antimicrobials. RESULTS: Twenty dogs and five cats had positive culture results. The most frequent bacterial genera isolated from dogs were Staphylococcus, Escherichia, Bacteroides, Clostridium and Pasteurella. The most frequent bacterial genera isolated from cats were Pasteurella and Bacteroides. Aerobic bacterial isolates from dogs had the highest percentage of susceptibility to amikacin, ceftiofur, gentamicin, imipenem, ticarcillin and trimethoprim-sulfamethoxazole. Aerobic bacterial isolates from dogs had the lowest percentage of susceptibility to ampicillin, clindamycin, erythromycin and penicillin. Antimicrobial resistance was uncommon among feline aerobic bacterial isolates. The most commonly identified routes of orbital bacteria introduction were extension from adjacent anatomical structures, penetrating exogenous trauma, and foreign bodies. CONCLUSIONS: Mixed aerobic and anaerobic bacterial infections of the orbit occur commonly in dogs and cats. On the basis of aerobic and anaerobic bacterial isolates and in vitro susceptibility testing of aerobic bacterial isolates, cephalosporins, extended-spectrum penicillins, potentiated-penicillins and carbapenems are recommended for initial antimicrobial therapy of orbital abscess in dogs and cats.

Corneal ulceration associated with naturally occurring canine herpesvirus-1 infection in two adult dogs.

CASE DESCRIPTION: An 8-year-old Labrador Retriever with diabetes mellitus in which bilateral phacoemulsification had been performed 3 weeks earlier was evaluated for acute onset of blepharospasm, and a 7-year-old Miniature Schnauzer with chronic immune-mediated thrombocytopenia was reevaluated for keratoconjunctivitis sicca that had been diagnosed 4 weeks earlier. CLINICAL FINDINGS: Dendritic corneal ulcerations were detected in both dogs. Canine herpesvirus-1 (CHV-1) was isolated from corneal swab specimens obtained during the initial evaluation of each dog and during recheck examinations performed until the ulcerations were healed. Canine herpesvirus-1 serum neutralization titers were detected in both dogs. Results of virus isolation from oropharyngeal and genital swab specimens were negative for both dogs. The isolated viruses were identified as CHV-1 via immunofluorescence, transmission electron microscopy, PCR assay, and gene sequencing. Negative controls for PCR assay and virus isolation included conjunctival swab specimens from 50 dogs without extraocular disease and corneal swab specimens from 50 dogs with corneal ulcers, respectively. TREATMENT AND OUTCOME: Lesions resolved in both dogs after topical administration of idoxuridine or trifluridine and discontinuation of topically administered immunosuppressive medications. CLINICAL RELEVANCE: To the authors' knowledge, this is the first report of corneal ulcerations associated with naturally occurring CHV-1 infection and may represent local ocular recrudescence of latent CHV-1 infection. The viruses isolated were identified as CHV-1, and the morphology, antigenicity, and genotype were similar to those for CHV-1 isolates obtained from a puppy that died from systemic CHV-1 infection.

Ciprofloxacin and ofloxacin aqueous humor concentrations after topical administration in dogs undergoing cataract surgery.

OBJECTIVE: To determine if preoperative topical administration of ciprofloxacin or ofloxacin results in aqueous humor drug concentrations that exceed the MIC(90) of common ocular contaminants in dogs undergoing cataract surgery. PROCEDURES: Twelve dogs were treated with topical 0.3% ciprofloxacin and 13 dogs with topical 0.3% ofloxacin once the night before surgery, and then with 1 drop of ciprofloxacin or ofloxacin every 15 min for 2 h immediately before surgery. Aqueous humor samples were taken from each eye immediately before the incision was made and frozen at -70 degrees C. First eye samples (S1) were taken closer to the time of topical treatments than second eye samples (S2). Samples were analyzed by high performance liquid chromatography (HPLC) at the North Carolina State University (NCSU) Clinical Pharmacology laboratory. RESULTS: In ciprofloxacin patients, S1 concentrations were 0.03-0.69 (0.17 median) microg/mL, and S2 concentrations were 0.09-0.95 (0.36 median) microg/mL. Aqueous humor concentrations did not exceed the MIC90 of Streptococcus sp. Few eyes (1/12 OU) exceeded the MIC90 for Staphylococcus sp. or Corynebacterium sp.; moderate numbers (5/12 S1; 8/12 S2) exceeded the MIC90 for E. coli. In ofloxacin patients, S1 concentrations were 0.48-2.81 (1.05 median) microg/mL, and S2 concentrations were 0.45-3.63 (1.30 median) microg/mL. Although few eyes (

Antibacterial agents for ocular therapeutics.

Ocular bacterial infections of animals take a variety of forms. The eyelid, external ocular surface, anterior segment, posterior segment,and orbit are all frequent targets. Effective management of ocular bacterial infections requires specific identification of the offending organism(s) combined with knowledge of the mechanisms of action and the therapeutic characteristics of available antibiotics.

Assessment of retinal degeneration in outbred albino mice.

Evaluation of a pharmaceutical's safety includes assessment of the potential for ophthalmologic toxicity. These nonclinical studies commonly use various outbred stocks of mice. Pretest indirect ophthalmoscopic examinations in the commonly used outbred stock Hsd:ICR(CD-1) indicated that retinal degeneration was a problem in this particular outbred stock of mice. This prompted the authors to examine other stocks of outbred mice routinely used in the performance of nonclinical safety studies. Groups of mice were observed over a 13-week period to determine the progression and changing incidence of retinal degeneration. Light intensity in the room and caging was measured during the study, and it was determined that light did not play a direct role in the progression of the retinal degeneration observed during the study. Histomorphologic examination of the mouse eyes was performed at the end of the study to confirm the presence of retinal degeneration observed after ophthalmoscopic examination. The incidence of retinal atrophy in the various outbred stocks of mice was: Crl:CFW(SW)BR (98.3%), Tac(SW)fBR (80%), Tac:Icr:Ha(ICR)fBR (75%), Hsd:ICR(CD-1) (43.3%), and Crl:CF-1BR (3.0%). Retinal atrophy was not observed in the following outbred mice stocks: Crl:CD-1(ICR)BR, HsdWin:CFW1, and Hsd:NSA(CF-1). On the basis of these findings, it is highly recommended that pretest ophthalmologic screening be performed on mice to obviate pre-existing conditions from confounding or invalidating nonclinical study results.

Squamous cell carcinoma associated with a periorbital mass in a veiled chameleon (Chamaeleo calyptratus).

This report describes a squamous cell carcinoma in a 1-year-old female veiled chameleon (Chamaeleo calyptratus). The lesion developed as a small (1 by 1 mm) left periocular discoloration of a scale never involving the eye. The mass was first diagnosed as an abscess, increased in size (4 by 8 by 3 mm), and recurred after two surgical resections combined with antibiotic therapy. Poor nutritional condition and egg production by the chameleon complicated management of this condition. The mass was removed surgically a third time at which point histopathologic evaluation revealed a locally invasive squamous cell carcinoma. Bacterial culture of the mass isolated a pure culture of Pseudomonas aeruginosa. Ceftazidime was administered at 20 mg/kg IM every 48 h for 20 days. The animal died 3 months later from complications during an ovariohysterectomy for pregnancy toxemia and oviduct inertia. Necropsy showed no local recurrence or metastasis of the tumor.