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.
Objective—To determine the total number of
Cryptosporidium parvum oocysts and Giardia spp
cysts shed by dairy calves during the period when
they are most at risk after natural infection.
Animals—478 calves naturally infected with C parvum
and 1,016 calves naturally infected with Giardia spp.
Procedure—Oocysts or cysts were enumerated from
fecal specimens. Distribution of number of oocysts or
cysts versus age was used to determine the best fitting
mathematic function. Number of oocysts or cysts
per gram of feces for a given duration of shedding
was computed by determining the area under the
curve. Total number of oocysts or cysts was calculated
by taking the product of the resultant and the
expected mass of feces.
Results—Intensity of C parvum oocyst shedding was
best described by a second-order polynomial function.
Shedding increased from 4 days of age, peaked
at day 12, and then decreased. An infected 6-day-old
calf would produce 3.89 X 1010 oocysts until 12 days
old. Pattern of shedding of Giardia spp cysts was best
described by exponential functions. Intensity of shedding
increased from 4 days of age, peaked at day 14,
and then decreased. An infected calf would produce
3.8 X 107 cysts from day 50 until day 56.
Conclusion and Clinical Relevance—The large
number of oocysts and cysts shed indicates that
shedding by dairy cattle poses a risk for susceptible
calves and people. Estimates reported here may be
useful to aid in designing cost-effective strategies to
manage this risk. (Am J Vet Res 2001;62:1612–1615)
Objective—To determine the effects of matrix metalloproteinase (MMP)-13, compared with interleukin (IL)-1α, on cartilage matrix molecule gene expression in a coculture system of equine cartilage explants and synoviocytes.
Sample Population—Articular cartilage and synovium specimens harvested from femoropatellar joints of 4 horses, aged 3 to 5 years.
Procedures—Synoviocytes were isolated and cocultured with cartilage explants. Cultures were treated with human recombinant MMP-13 (1, 25, or 100 ng/mL) or IL-1α (0.01, 0.1, 1.0, or 10 ng/mL) for 96 hours, with medium exchange at 48 hours. Cartilage extracts and media were analyzed for glycosaminoglycan (GAG) content, and results were adjusted to cartilage DNA content. Quantitative PCR was performed on mRNA from cartilage (MMP-3, MMP-13, aggrecan, and collagen type IIB [COL2A1]) and synoviocytes (MMP-3 and MMP-13), and results were adjusted to 18S ribosomal subunit mRNA expression. Treatments were performed in triplicate, and the experiment was repeated 4 times.
Results—Cultures treated with MMP-13 or IL-1α had increased media GAG concentration at 48 and 96 hours. Aggrecan and COL2A1 mRNA expression were increased by application of MMP-13 or IL-1α. Gene expression of the catabolic mediator, MMP-3, in cartilage and synoviocytes was increased in cultures treated with MMP-13 or IL-1α. Expression of MMP-13 mRNA in cartilage was increased by IL-1α, but decreased in synoviocytes by MMP-13 treatment.
Conclusions and Clinical Relevance—Results support the use of recombinant MMP-13 in a coculture system of synoviocytes and cartilage explants for the study of osteoarthritis.
Objective—To identify risk factors associated with Cryptosporidium parvum infection in dairy calves.
Animals—108 case animals and 283 control animals.
Procedures—Case animals were calves infected with C parvum, and controls were infected with Cryptosporidium bovis (n = 67) or calves not infected with Cryptosporidium spp. Fecal samples were tested via the flotation concentration method for Cryptosporidium spp. Samples were genotyped by sequencing of the 18s rRNA gene. Associations between host, management, geographic, and meteorologic factors and Cryptosporidium genotype were assessed.
Results—Younger calves and calves housed in a cow barn were more likely to be infected with both genotypes. Herd size and hay bedding were associated with an increased risk of infection with C parvum, and Jersey breed was a risk factor for C bovis infection. Compared with a flat surface, a steeper slope was significantly associated with a decreased likelihood of infection with both genotypes, and precipitation influenced the risk of C parvum infection only.
Conclusions and Clinical Relevance—Risk factors for calf infection with C parvum differed from those for infection with C bovis. Results may be useful to help design measures that reduce animal exposure and decrease public health risk and economic losses associated with C parvum infection in cattle.
To describe the in vivo confocal microscopy (IVCM) features of the corneal epithelium and stroma in dogs and cats with herpetic dendritic ulcerative keratitis.
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).
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.
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.
Case Description—6 alpaca crias from a single farm were examined because of diarrhea (n = 4) or decreased fecal production (n = 2).
Clinical Findings—Cryptosporidium parvum was identified by means of fecal flotation in samples from 5 of the 6 crias, and a diagnosis of cryptosporidiosis was made. In the remaining cria, a presumptive diagnosis of cryptosporidiosis was made. Three people involved in caring for the crias from this farm were subsequently confirmed to have cryptosporidiosis, and 3 other people were suspected to have cryptosporidiosis. Sequence analysis of the ssu rDNA gene loci confirmed C parvum as the causative agent in 4 of the 6 crias. Subsequent evaluation of the farm revealed 2 additional crias confirmed to have cryptosporidiosis. Stocking densities on the farm were high, with approximately 20 adults/acre in some pastures.
Treatment and Outcome—All 6 hospitalized crias were given supportive treatment consisting of antimicrobials, gastroprotectants, and fluids. All but 1 survived. Farm owners were advised to decrease stocking density on the farm.
Clinical Relevance—Findings suggested that zoonotic transmission of C parvum from alpacas to humans can occur.
OBJECTIVE To evaluate the effects of adjunctive treatment with autologous platelet-rich plasma (PRP) on corneal reepithelialization, vascularization, and fibrosis in dogs with spontaneous chronic corneal epithelial defects (SCCEDs).
ANIMALS 40 client-owned dogs with uncomplicated SCCEDs.
PROCEDURES All dogs were treated with diamond-burr epithelial debridement (DBD) of affected eyes, topical tobramycin solution and atropine sulfate ointment application, and Elizabethan collar placement for 4 weeks. Dogs were randomly assigned to topical ocular administration of autologous PRP (n = 20) or artificial tear solution (control group; 20) 4 times daily for 28 days. Recheck examinations were performed approximately 2 and 4 weeks after treatment began to evaluate SCCEDs for corneal reepithelialization, and semiquantitative corneal vascularization and corneal fibrosis scores were assigned according to affected corneal surface area. Results were compared between groups.
RESULTS All dogs completed the study. The SCCEDs had completely reepithelialized in 11 (55%) control dogs and 12 (60%) PRP-treated dogs by the 2-week reevaluation, and in 15 (75%) control dogs and 18 (90%) PRP-treated dogs by the 4-week reevaluation. No significant differences were identified between groups in these proportions nor in mean differences from pretreatment scores for corneal vascularization and fibrosis.
CONCLUSIONS AND CLINICAL RELEVANCE In this preliminary study involving dogs with uncomplicated SCCEDs, topical PRP administered as an adjunctive treatment following DBD had no significant effect on healing. A larger study is warranted to support or refute these findings and to determine the effects of adjunctive PRP treatment for dogs with complicated SCCEDs.
Objective—To determine whether equine motor neuron disease (EMND) could be induced in adult horses fed a diet low in vitamin E and high in copper and iron.
Animals—59 healthy adult horses.
Procedure—Horses in the experimental group (n = 8) were confined to a dirt lot and fed a concentrate low in vitamin E and high in iron and copper in addition to free-choice grass hay that had been stored for 1 year. Control horses (n = 51) were fed a concentrate containing National Research Council–recommended amounts of copper, iron, and vitamin E. The hay fed to control horses was the same as that fed to experimental horses, but it had not been subjected to prolonged storage. Control horses had seasonal access to pasture, whereas experimental horses had no access to pasture. Horses that developed clinical signs of EMND were euthanatized along with an age-matched control horse to determine differences in hepatic concentrations of vitamin E, vitamin A, copper, iron, and selenium.
Results—4 experimental horses developed clinical signs of EMND. Plasma concentrations of vitamin E decreased in all 8 experimental horses. There were no significant changes in plasma concentrations of vitamin A, selenium, and copper or serum concentrations of ferritin. There were no significant differences in those analytes between experimental horses with EMND and experimental horses that did not develop EMND. No control horses developed EMND.
Conclusions and Clinical Relevance—Results suggest that lack of access to pasture, dietary deficiency of vitamin E, or excessive dietary copper are likely risk factors for EMND.
Objective—To determine the risk posed by
Cryptosporidium parvum and Cryptosporidium
hominis from dairy cattle in the New York City watershed
Sample Population—Samples from cattle at risk for
shedding Cryptosporidium organisms on randomly
selected dairy farms in the NYCW.
Procedure—Feces were collected for 4 years from
calves at risk for infection on 37 dairies. Oocysts were
detected by use of centrifugation concentration-flotation
microscopy. The DNA was directly isolated from
fecal samples and used to amplify fragments of the
small subunit ribosomal RNA and thrombospondinrelated
adhesion protein C-2 genes by use of nested
polymerase chain reaction assays. Small subunit ribosomal
RNA fragments were restriction digested by
the enzyme VspI and thrombospondin-related adhesion
protein C-2 fragments were digested by Eco91I
to distinguish between C hominis (formerly known as
genotype 1) and C parvum (formerly known as genotype
Results—Of 437 fecal samples examined, 214 contained
oocysts. Amplicons were generated for 200
samples. We can be certain, with 95% confidence,
that cattle in the NYCW did not harbor C hominis.
Conclusions and Clinical Relevance—Cryptosporidium
infections in cattle are under examination
because of the potential contamination of public waters
by manure. Although cattle may be the source of
zoonotic infection via C parvum, they pose little risk for
C hominis (the strain commonly isolated from humans
in waterborne outbreaks of disease). Other sources of
oocysts should be considered when investigating outbreaks
attributable to contaminated urban drinking
water because cattle pose only a small risk via shedding
of C hominis. (Am J Vet Res 2005;66:413–417).
Objective—To compare concentrations of trace minerals
in the spinal cord of horses with equine motor
neuron disease (EMND) with those of horses without
neurologic disease (control horses).
Animals—24 horses with EMND and 22 control horses.
Procedure—Spinal cord trace mineral concentrations
in horses with EMND and control horses were analyzed
by use of inductively coupled plasma atomic
emission spectroscopy (calcium, phosphorus, sodium,
potassium, magnesium, copper, iron, manganese,
nickel, zinc, aluminum, cobalt, and chromium),
atomic absorption spectrophotometry (lead and
cadmium), flameless atomic absorption (mercury),
and fluorometry (selenium).
Results—Copper concentration was significantly higher
in the spinal cord of horses with EMND, compared
with control horses; spinal cord concentrations of all
other trace minerals were similar between groups.
Conclusion and Clinical Relevance—Among spinal
cord trace minerals investigated in the study, only
copper concentrations were significantly different
between horses with EMND and horses without neurologic
disease, which suggests that copper may be
involved in the pathogenesis of EMND. An hypothesis
of oxidative injury in this disease is supported by
the finding of increased copper concentrations in the
spinal cord and by low vitamin E concentrations
reported by other researchers. (Am J Vet Res 2000;