Objective—To assess effects of disease severity, sampling instrument, and processing technique on extracted DNA yield and detection rate for feline herpesvirus-1 (FHV-1) via PCR assay.
Sample Population—Crandell-Rees feline kidney (CRFK) cells grown in vitro and conjunctival samples from 40 eyes of 20 cats.
Procedures—Samples of CRFK cells (collected by use of a swab or cytology brush, with or without suspension in PBS solution) underwent DNA extraction; DNA yield was quantified spectrophotometrically. In affected cats, signs of herpetic disease were subjectively assessed. Conjunctival swab and brush samples were collected bilaterally for measurement of DNA concentration; a defined mass (DM) of DNA and defined volume (DV) of sample were assessed for FHV-1 via PCR assays.
Results—For CRFK cells, DNA yields from unsuspended swabs and brushes were greater than for suspended swabs and brushes; suspended swab samples yielded less DNA than suspended brush samples. For conjunctival samples, DNA yields from swabs were greater than for brushes. Clinical score was not correlated with double-stranded DNA yield collected via either sampling instrument; however, cats with FHV-1–positive assay results had higher clinical scores than cats with FHV-1–negative results. Detection of FHV-1 in swab and brush samples was similar. Double-stranded DNA yield and FHV-1 detection were inversely related via DM-PCR assay. The DV-PCR assay had a significantly higher FHV-1 detection rate than the DM-PCR assay.
Conclusions and Clinical Relevance—The DV-PCR assay of DNA extracted from an unsuspended swab sample was the preferred method for assessment of conjunctival shedding of FHV-1 in cats.
Objective—To detect feline herpesvirus type 1 (FHV-1) in blood of cats undergoing experimental primary herpetic disease or with spontaneous disease presumed to be caused by FHV-1 reactivation.
Animals—6 young specific-pathogen–free (SPF) cats and 34 adult cats from a shelter.
Procedures—Conjunctiva and nares of SPF cats were inoculated with FHV-1, and cats were monitored for 21 days. Periodically, blood was collected for CBC, serum biochemical analyses, and detection of FHV-1 DNA via PCR assay. For shelter cats, a conjunctival swab specimen was collected for FHV-1 PCR assay, and blood mononuclear cells were tested via virus isolation (with or without hydrocortisone) and FHV-1 PCR assay.
Results—All SPF cats developed clinical and clinicopathologic evidence of upper respiratory tract and ocular disease only. Via PCR assay, FHV-1 DNA was detected in blood of all SPF cats at least once between 2 and 15 days after inoculation. Feline herpesvirus type 1 DNA was detected in conjunctival swabs of 27 shelter cats; 25 had clinical signs of herpetic infection. However, virus was not isolated from mononuclear cell samples of any shelter cat regardless of passage number or whether hydrocortisone was present in the culture medium; FHV-1 DNA was not detected in any mononuclear cell sample collected from shelter cats.
Conclusions and Clinical Relevance—A brief period of viremia occurred in cats undergoing primary herpetic disease but not in cats undergoing presumed recrudescent herpetic disease. Viremia may be important in the pathogenesis of primary herpetic disease but seems unlikely to be associated with recrudescent disease.
Objective—To determine ocular tissue drug concentrations after topical ocular administration of 0.3% ciprofloxacin and 0.5% moxifloxacin in ophthalmologically normal horses.
Animals—24 ophthalmologically normal adult horses.
Procedures—0.3% ciprofloxacin and 0.5% moxifloxacin solutions (0.1 mL) were applied to the ventral conjunctival fornix of 1 eye in each horse as follows: group 1 (n = 8) at 0, 2, 4, and 6 hours; group 2 (8) at 0, 2, 4, 6, and 10 hours; and group 3 (8) at 0, 2, 4, 6, 10, and 14 hours. Tears, cornea, and aqueous humor (AH) were collected at 8, 14, and 18 hours for groups 1, 2, and 3, respectively. Drug concentrations were determined via high-performance liquid chromatography.
Results—Median (25th to 75th percentile) concentrations of ciprofloxacin for groups 1, 2, and 3 in tears (μg/mL) were 53.7 (25.5 to 88.8), 48.5 (19.7 to 74.7), and 24.4 (15.4 to 67.1), respectively; in corneal tissue (μg/g) were 0.95 (0.60 to 1.02), 0.37 (0.32 to 0.47), and 0.48 (0.34 to 0.95), respectively; and in AH were lower than the limit of quantification in all groups. Concentrations of moxifloxacin for groups 1, 2, and 3 in tears (μg/mL) were 188.7 (44.5 to 669.2), 107.4 (41.7 to 296.5), and 178.1 (70.1 to 400.6), respectively; in corneal tissue (μg/g) were 1.84 (1.44 to 2.11), 0.78 (0.55 to 0.98), and 0.77 (0.65 to 0.97), respectively; and in AH (μg/mL) were 0.06 (0.04 to 0.08), 0.03 (0.02 to 0.05), and 0.02 (0.01 to 0.04), respectively. Corneal moxifloxacin concentrations were significantly higher in group 1 than groups 2 and 3.
Conclusions and Clinical Relevance—After topical ocular administration, fluoroquinolones can reach therapeutic concentrations in tears and corneal tissue of horses, even when there is an intact epithelium.
Procedures—Medical records of dogs with primary glaucoma that underwent unilateral gonioimplant placement (in 2000 through 2008), during which a temporalis muscle fascia graft (n = 8) or porcine intestinal submucosa (1) was used to cover the implant tube as it exited the globe, were reviewed. All dogs were treated with mitomycin C in the conjunctival pocket intraoperatively and with tissue plasminogen activator immediately after surgery; 1% prednisolone acetate was applied to the implanted eye daily until failure of the implant. Medical intervention or additional surgery was performed when intraocular pressures (IOPs) were > 20 mm Hg or progressively increasing values were detected.
Results—After gonioimplant placement, IOP was controlled for a variable period in all dogs. Subsequently, IOP exceeded 20 mm Hg in 7 dogs (median postoperative interval, 326 days). Median interval to vision loss despite interventional surgery was 518 days (range, 152 to 1,220 days). Surgical intervention was necessary in 4 dogs to maintain satisfactory IOP. Implant extrusion attributable to conjunctival dehiscence or necrosis occurred in 4 dogs. At 365 days after surgery, 8 dogs retained vision, and 5 dogs retained vision throughout follow-up.
Conclusions and Clinical Relevance—In dogs with medically refractory primary glaucoma, placement of a gonioimplant appears to be effective in maintaining vision.
Objective—To determine within a cat shelter effects of dietary lysine supplementation on nasal and ocular disease and detection of nucleic acids of Chlamydophila felis, feline calicivirus (FCV), and feline herpesvirus (FHV-1).
Animals—261 adult cats.
Procedures—Cats were fed a diet containing 1.7% (basal diet; control cats) or 5.7% (supplemented diet; treated cats) lysine for 4 weeks. Plasma concentrations of lysine and arginine were assessed at the beginning (baseline) and end of the study. Three times a week, cats were assigned a clinical score based on evidence of nasal and ocular disease. Conjunctival and oropharyngeal swab specimens were tested for FHV-1, FCV, and C felis nucleic acids once a week.
Results—Data were collected from 123, 74, 59, and 47 cats during study weeks 1, 2, 3, and 4, respectively. By study end, plasma lysine concentration in treated cats was greater than that in control cats and had increased from baseline. There was no difference between dietary groups in the proportion of cats developing mild disease. However, more treated cats than control cats developed moderate to severe disease during week 4. During week 2, FHV-1 DNA was detected more commonly in swab specimens from treated versus control cats.
Conclusions and Clinical Relevance—Dietary lysine supplementation in the amount used in our study was not a successful means of controlling infectious upper respiratory disease within a cat shelter. Rather, it led to increases in disease severity and the incidence of detection of FHV-1 DNA in oropharyngeal or conjunctival mucosal swab specimens at certain time points.