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 estimate serovar-specific prevalence
of leptospirosis by use of veterinary teaching hospital
and laboratory submission data; describe annual and
seasonal patterns of leptospirosis; and identify risk
factors for age, sex, and breed.
Animals—90 dogs with leptospirosis.
Procedures—Hospital records of dogs examined at
Purdue University Veterinary Teaching Hospital with a
diagnosis of leptospirosis and laboratory records of
dogs from which sera were tested for antibodies
against Leptospira spp at Purdue University Animal
Disease Diagnostic Laboratory from 1997 through 2002
were reviewed. The likely infecting Leptospira serovar
was identified. Seasonal and annual prevalences were
calculated by use of hospital population at risk (hospital
cases) or serologic testing submissions (diagnostic laboratory
cases). Age-, sex-, and breed-specific risk factors
for hospital cases were estimated by odds ratios.
Results—Of the 39 hospitalized dogs identified, 34
had been serologically tested, and 22 of those were
infected with Leptospira kirschneri serovar grippotyphosa.
Of the 51 diagnostic laboratory cases, 59%
had a reciprocal titer ≥ 800 against serovar grippotyphosa.
Diagnostic laboratory cases were more common
in summer, whereas hospital cases of leptospirosis
were more common in fall. Male dogs were
at significantly greater risk of leptospirosis than
female dogs; and dogs 4 to 6.9 years old were at significantly
greater risk than dogs < 1 year old.
Conclusions and Clinical Relevance—L kirschneri
serovar grippotyphosa infection was associated with
most cases of leptospirosis in dogs. Use of an effective
vaccine that includes this serovar is advisable for
dogs at risk of leptospirosis. (J Am Vet Med Assoc 2004;224:1958–1963)
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 use results of microscopic agglutination tests (MATs) conducted at a commercial veterinary diagnostic laboratory to determine temporal and demographic distributions of positive serologic test results for leptospirosis in dogs and identify correlations among results for various Leptospira serovars.
Study Population—MAT results for 33,119 canine serum samples submitted to a commercial veterinary diagnostic laboratory from 2000 through 2007.
Procedures—Electronic records of MAT results for dogs were obtained from a veterinary diagnostic laboratory. Seropositivity for antibodies against Leptospira serovars was determined by use of a cutoff titer of ≥ 1:1,600 to reduce the possible impact of postvaccinal antibodies on results. Correlations between results for all possible pairs of serovars were calculated by ordinal ranking of positive (≥ 1:100) antibody titer results.
Results—2,680 samples (8.1%; 95% confidence interval [CI], 7.8% to 8.4%) were seropositive for antibodies against Leptospira serovars. The highest percentage of positive MAT results was for the year 2007 (10.2%; 95% CI, 9.5% to 10.9%) and for the months of November and December during the study period. Antibodies were most common against serovars Autumnalis, Grippotyphosa, Pomona, and Bratislava. Seroprevalence of leptospirosis was lowest for dogs > 10 years of age but was similar across other age strata.
Conclusions and Clinical Relevance—Leptospirosis can affect dogs of small and large breeds and various ages. Although an increase in proportions of positive MAT results was evident in the fall, monthly and annual variations suggested potential exposure in all months. Because of the limitations of MAT results and the limited number of serovars used in the test, bacterial culture should be used to identify infective Leptospira serovars.
Objective—To determine the incidence of vaccine-associated adverse events (VAAEs) diagnosed within 30 days of vaccination in cats and characterize risk factors for their occurrence.
Design—Retrospective cohort study.
Animals—496,189 cats vaccinated at 329 hospitals.
Procedures—Electronic records were searched for VAAEs that occurred after vaccine administration classified by practitioners as nonspecific vaccine reaction, allergic reaction, urticaria, shock, or anaphylaxis. Clinical signs and treatments were reviewed. The association between potential risk factors and a VAAE occurrence was estimated via multivariate logistic regression.
Results—2,560 VAAEs were associated with administration of 1,258,712 doses of vaccine to 496,189 cats (51.6 VAAEs/10,000 cats vaccinated). The risk of a VAAE significantly increased as the number of vaccines administered per office visit increased. Risk was greatest for cats approximately 1 year old; overall risk was greater for neutered versus sexually intact cats. Lethargy with or without fever was the most commonly diagnosed VAAE. No localized reactions recorded in the 30-day period were subsequently diagnosed as neoplasia when followed for 1 to 2 years.
Conclusions and Clinical Relevance—Although overall VAAE rates were low, young adult neutered cats that received multiple vaccines per office visit were at the greatest risk of a VAAE within 30 days after vaccination. Veterinarians should incorporate these findings into risk communications and limit the number of vaccinations administered concurrently to cats.
Objective—To determine incidence rates and potential
risk factors for vaccine-associated adverse events
(VAAEs) diagnosed within 3 days of administration in
Design—Retrospective cohort study.
Animals—1,226,159 dogs vaccinated at 360 veterinary
Procedure—Electronic records from January 1, 2002,
through December 31, 2003, were searched for possible
VAAEs (nonspecific vaccine reaction, allergic
reaction, urticaria, or anaphylaxis) diagnosed within 3
days of vaccine administration. Information included
age, weight, sex, neuter status, and breed. Specific
clinical signs and treatments were reviewed in a random
sample of 400 affected dogs. The association
between potential risk factors and a VAAE was estimated
by use of multivariate logistic regression.
Results—4,678 adverse events (38.2/10,000 dogs
vaccinated) were associated with administration of
3,439,576 doses of vaccine to 1,226,159 dogs. The
VAAE rate decreased significantly as body weight
increased. Risk was 27% to 38% greater for neutered
versus sexually intact dogs and 35% to 64% greater
for dogs approximately 1 to 3 years old versus 2 to 9
months old. The risk of a VAAE significantly increased
as the number of vaccine doses administered per
office visit increased; each additional vaccine significantly
increased risk of an adverse event by 27% in
dogs ≤ 10 kg (22 lb) and 12% in dogs > 10 kg.
Conclusions and Clinical Relevance—Young adult
small-breed neutered dogs that received multiple vaccines
per office visit were at greatest risk of a VAAE
within 72 hours after vaccination. These factors
should be considered in risk assessment and risk
communication with clients regarding vaccination.
(J Am Vet Med Assoc 2005;227:1102–1108)