Objective—To estimate the association between climate
and airborne pollen and fungal factors and
chronic obstructive pulmonary disease (COPD) in
Sample Population—Data from 1,444 horses with a
diagnosis of COPD.
Procedure—The Veterinary Medical Database was
used to identify records of horses admitted to veterinary
teaching hospitals in the United States and
Canada between 1990 and 1999. Rainfall, mean minimum
and maximum temperature, and maximum
monthly pollen and fungal spore (mold) counts recorded
at the city closest to where the hospital is located
were identified for each month data were reported to
the Veterinary Medical Database. Associations
between climatic and aeroallergen data and monthly
prevalence of COPD were estimated by use of crosscorrelation
and logistic regression models.
Results—Significant positive correlations were found
between prevalence of COPD and rainfall 3 months
previously, minimum temperature 1 and 2 months previously,
total pollen counts measured 3 months previously,
and total mold counts measured during the
same month and 1 month previously.
Conclusions and Clinical Relevance—Outdoor
aeroallergens and climatic factors may contribute to
the occurrence of COPD in horses. (Am J Vet Res
Objective—To determine aqueous humor flow rate (AHFR) in an avian species by use of anterior segment fluorophotometry.
Animals—9 healthy red-tailed hawks (Buteo jamaicensis; 4 males and 5 females) that ranged from 8 months to 8 years of age.
Procedures—A protocol was developed for fluorophotometric determination of AHFR. Topical administration of 10% fluorescein was used to load the corneas, and corneal and aqueous humor fluorescein concentrations were measured approximately 5, 6.5, and 8 hours later. Concentration-versus-time plots were generated, and slopes and cornea-to-aqueous humor concentration ratios from these plots were used to manually calculate flow rates.
Results—Mean ± SD AHFRs for the right eye, left eye, and both eyes were 3.17 ± 1.36 μL/min (range, 1.67 to 6.21 μL/min), 2.86 ± 0.88 μL/min (range, 2.04 to 4.30 μL/min), and 2.90 ± 0.90 μL/min (range, 1.67 to 4.42 μL/min), respectively. The AHFRs were similar for right and left eyes. These flow rates represented a mean aqueous humor transfer coefficient of 0.0082/min, which is similar to that of mammalian species.
Conclusions and Clinical Relevance—The AHFR in red-tailed hawks was similar to that of most mammalian species, and the fractional egress was almost identical to that of other species. This information will allow a greater understanding of aqueous humor flow in avian eyes, which is crucial when evaluating diseases that affect avian eyes as well as medications that alter aqueous humor flow.
Objective—To identify risk factors for recurrent airway
obstruction (RAO) among horses examined at
veterinary teaching hospitals in North America.
Design—Retrospective case-control study.
Animals—1,444 horses with RAO and 1,444 control
horses examined for other reasons.
Procedure—The Veterinary Medical Database was
searched for records of horses in which RAO was
diagnosed. A control group was identified by randomly
selecting a horse with a diagnosis other than RAO
that matched the institution and year of admission for
each of the horses with RAO. Information obtained
included hospital, admission year and month, age,
sex, breed, and discharge status. The association
between risk factors and diagnosis of RAO was estimated
with logistic regression models.
Results—The risk of RAO increased significantly with
age, with horses ≥ 7 years old being 6 to 7 times as
likely to have RAO as were horses ≤ 4 years old.
Thoroughbreds were 3 times as likely to have RAO as
were ponies. Horses were 1.6 and 1.5 times as likely
to be examined because of RAO during winter and
spring, respectively, than they were during summer.
Conclusions and Clinical Relevance—Results suggest
that RAO was more likely to be diagnosed in
females, horses ≥ 4 years old, and Thoroughbreds and
that RAO has a seasonal distribution. (J Am Vet Med
Objective—To compare gentamicin concentrations achieved in synovial fluid and joint tissues during IV administration and continuous intra-articular (IA) infusion of the tarsocrural joint in horses.
Animals—18 horses with clinically normal tarsocrural joints.
Procedure—Horses were assigned to 3 groups (6 horses/group) and administered gentamicin (6.6 mg/kg, IV, q 24 h for 4 days; group 1), a continuous IA infusion of gentamicin into the tarsocrural joint (50 mg/h for 73 hours; group 2), or both treatments (group 3). Serum, synovial fluid, and joint tissue samples were collected for measurement of gentamicin at various time points during and 73 hours after initiation of treatment. Gentamicin concentrations were compared by use of a Kruskal-Wallis ANOVA.
Results—At 73 hours, mean ± SE gentamicin concentrations in synovial fluid, synovial membrane, joint capsule, subchondral bone, and collateral ligament of group 1 horses were 11.5 ± 1.5 μg/mL, 21.1 ± 3.0 μg/g, 17.1 ± 1.4 μg/g, 9.8 ± 2.0 μg/g, and 5.9 ± 0.7 μg/g, respectively. Corresponding concentrations in group 2 horses were 458.7 ± 130.3 μg/mL, 496.8 ± 126.5 μg/g, 128.5 ± 74.2 μg/g, 99.4 ± 47.3 μg/g, and 13.5 ± 7.6 μg/g, respectively. Gentamicin concentrations in synovial fluid, synovial membrane, and joint capsule of group 1 horses were significantly lower than concentrations in those samples for horses in groups 2 and 3.
Conclusions and Clinical Relevance—Continuous IA infusion of gentamicin achieves higher drug concentrations in joint tissues of normal tarsocrural joints of horses, compared with concentrations after IV administration.
Objective—To determine if clopidogrel enhanced the
thrombolytic rate of tissue-plasminogen activator (t-PA) on an in vitro feline whole blood thrombosis
Animals—9 purpose-bred cats.
Procedure—Blood obtained from cats before (baseline)
and after treatment with clopidogrel (75 mg, PO,
q 24 h for 3 days) was anticoagulated with sodium citrate
(9:1 volume-to-volume ratio) to which 1 µCi of I125-
fibrinogen was added. Thrombi were formed by the
addition of calcium chloride and bovine thrombin.
Thrombi were placed into autologous plasma to
which 0.1 mg of t-PA was added. Plasma samples
were collected at different time points to determine
the amount of released I125-fibrin split products.
Thrombolytic rates were calculated by determining
the time to 25%, 50%, and 75% thrombolysis (t25,
t50, and t75, respectively). Confidence intervals for t25,
t50, and t75 at baseline were compared with those
Results—There were no significant differences in
thrombolytic rates between values obtained at baseline
and after clopidogrel treatment (t25, 18.0 vs 18.5
minutes; t50, 63.3 vs 65.6 minutes; and t75, 163.0 vs
170.1 minutes, respectively).
Conclusions and Clinical Relevance—Clopidogrel
did not have an effect on the rate of thrombolysis of
feline whole blood thrombi induced by t-PA in this in
vitro model. (Am J Vet Res 2004;65:715–719)
Objective—To determine the association between
soil type and paratuberculosis in cattle.
Sample Population—Soil samples and test results
for paratuberculosis in 92 Indiana cattle herds.
Procedure—Testing records from herds in which ≥ 20
cattle were tested for paratuberculosis by use of an
ELISA between 1998 and 2002 were identified. Soil
type was characterized on the basis of herd location.
Clusters of herds with seroprevalence greater than
the median seroprevalence were identified.
Association between clusters and soil types was estimated
by logistic regression, adjusted for herd type
(dairy or beef).
Results—A spatial cluster of greater than the median
seroprevalence was identified in northeast Indiana.
Soils with low silt content were associated (odds ratio
[OR], 7.2; 95% confidence interval [CI], 2.1 to 24.5)
with this cluster. Adjusting for herd type did not substantially
alter this association (OR, 6.7). Herds located
in areas with sandy loam (OR, 6.2; 95% CI, 1.4 to
27.4) and loam (OR, 3.6; 95% CI, 1.0 to 13.2) soils
were also more likely to be within the cluster of
greater than the median seroprevalence. Herds located
in areas of silt loam soils were less likely (OR, 0.2;
95% CI, 0.1 to 0.7) to be included in this cluster.
Conclusions and Clinical Relevance—Spatial distribution
of herds with greater than the median seroprevalence
of paratuberculosis was associated with
soil characteristics. Survival of Mycobacterium avium subsp paratuberculosis may be enhanced by silt or
sand content in loamy soils. These results may be
used to modify paratuberculosis control programs.
( Am J Vet Res 2004;65:10–14)
Objective—To identify environmental risk factors for
Animals—36 dogs with leptospirosis and 138 dogs
seronegative for leptospirosis as determined by
microscopic agglutination test for antibodies against
Procedure—Medical records of dogs evaluated for
leptospirosis from 1997 though 2002 were identified.
Owner address was used to geocode locations of
dogs, and location-specific environmental risk factor
data were obtained by use of a geographic information
system. Risk of leptospirosis was estimated by
odds ratios, controlling for potential confounding by
dog age, sex, and breed.
Results—Leptospirosis in 19 of the 30 dogs in which
an infecting Leptospira serovar could be identified
was associated with Leptospira kirschneri serovar
grippotyphosa infection. Dogs in which a diagnosis of
leptospirosis was made, and dogs with leptospirosis
caused by L kirschneri serovar grippotyphosa, were
more likely to have addresses located in areas classified
as rural in 1990 but urban in 2000. By use of information
on recent urbanization and a logistic regression
model, the status of 81.6% and 89.8% of dogs
with leptospirosis and leptospirosis caused by serovar
grippotyphosa, respectively, were correctly classified.
Other environmental variables (proximity to streams,
recreational areas, farmland, wetlands, areas subject
to flooding, and areas with poor drainage; annual rainfall;
and county cattle or pig population) did not significantly
improve accuracy of classification.
Conclusions and Clinical Relevance—Dogs in periurban
areas are at greater risk of leptospirosis.
Vaccination of dogs in these areas to protect against
leptospirosis should be considered. (J Am Vet Med
Objective—To determine whether there was a temporal
trend in prevalence of leptospirosis among dogs
in the United States and Canada and to determine
whether age, sex, and breed were risk factors for the
Animals—1,819,792 dogs examined at 22 veterinary
teaching hospitals between 1970 and 1998.
Procedures—The Veterinary Medical Data Base was
searched for records of dogs in which a diagnosis of
leptospirosis was made, and hospital prevalence was
calculated. Logistic regression was used to examine
the association between leptospirosis and age, sex,
Results—677 dogs with leptospirosis were identified.
Thus, hospital prevalence was 37 cases/100,000
dogs examined. A significant increase in leptospirosis
prevalence between 1983 and 1998 was identified.
Male dogs were at significantly greater risk of leptospirosis
than were female dogs; dogs between 4
and 6.9 years old and between 7 and 10 years old
were at significantly greater risk than dogs < 1 year
old; and herding dogs, hounds, working dogs, and
mixed-breed dogs were at significantly greater risk
than companion dogs.
Conclusions and Clinical Relevance—The prevalence
of leptospirosis among dogs examined at veterinary
teaching hospitals in the United States and
Canada has increased significantly since 1983. Male
dogs of working and herding breeds were at greater
risk. (J Am Vet Med Assoc 2002;220:53–58)
Objective—To determine whether West Nile virus (WNV) disease hyperendemic foci (hot spots) exist within the horse population in Texas and, if detected, to identify the locations.
Sample Population—Reports of 1,907 horses with WNV disease in Texas from 2002 to 2004.
Procedures—Case data with spatial information from WNV epidemics occurring in 2002 (1,377 horses), 2003 (396 horses), and 2004 (134 horses) were analyzed by use of the spatial scan statistic (Poisson model) and kriging of empirical Bayes smoothed county attack rates to determine locations of horses with WNV disease in which affected horses were consistently (in each of the 3 study years) clustered (hyperendemic foci, or hot spots).
Results—2 WNV hot spots in Texas, an area in northwestern Texas and an area in eastern Texas, were identified with the scan statistic. Risk maps of the WNV epidemics were qualitatively consistent with the hot spots identified.
Conclusions and Clinical Relevance—WNV hot spots existed within the horse population in Texas (2002 to 2004). Knowledge of disease hot spots allows disease control and prevention programs to be made more efficient through targeted surveillance and education.
Objective—To determine clinical findings, complications, and outcome of septic synovitis in which continuous intrasynovial antimicrobial infusion (CIAI) was used for local antimicrobial delivery in horses.
Design—Retrospective case series.
Animals—22 adult horses and 9 foals (horses < 1 year of age).
Procedures—Records of horses with septic synovitis that had CIAI during treatment were reviewed. The association between clinical variables and whether horses performed their intended use following treatment was determined.
Results—42 synovial cavities were treated via CIAI. Twenty-nine cases were chronic (> 7 days) in nature, 15 had been refractory to standard treatments, and 13 synovial infections had associated osteomyelitis. Mean duration from infection to initiation of CIAI was 19.7 days, and mean duration of CIAI was 6.1 days. Temporary discharge from the catheter site at the time of removal was evident in 8 horses. Dysfunction of the infusion system occurred in 2 horses and was corrected during the course of treatment. No long-term complications were reported. Thirty-nine (93%) synovial infections in 29 (94%) horses were resolved. Twenty adult horses and 8 foals were discharged from the hospital, and 19 of 24 horses with long-term follow-up performed their intended use.
Conclusions and Clinical Relevance—CIAI was a useful adjunctive treatment for septic synovitis and allowed intrasynovial antimicrobial delivery into a variety of synovial cavities.