Extracellular Bartonella henselae and artifactual intraerythrocytic pseudoinclusions in experimentally infected cats

Blood, spleen and liver of specific pathogen-free (SPF) cats and SPF cats experimentally infected with Bartonella henselae were examined. Using immunohistochemical labeling, no intracellular B. henselae were observed in tissues of any cats, but extracellular B. henselae were detected in tissues of infected cats. Pseudoinclusions were detected in erythrocytes of all cats using electron microscopy.     

Herbicide exposure and the risk of transitional cell carcinoma of the urinary bladder in Scottish Terriers

OBJECTIVE: To determine whether exposure to lawn or garden chemicals was associated with an increased risk of transitional cell carcinoma (TCC) of the urinary bladder in Scottish Terriers. DESIGN: Case-control study. ANIMALS: 83 Scottish Terriers with TCC (cases) and 83 Scottish Terriers with other health-related conditions (controls). PROCEDURE: Owners of study dogs completed a written questionnaire pertaining to exposure to lawn or garden chemicals during the year prior to diagnosis of TCC for case dogs and during a comparable period for control dogs. RESULTS: The risk of TCC was significantly increased among dogs exposed to lawns or gardens treated with both herbicides and insecticides (odds ratio [OR], 7.19) or with herbicides alone (OR, 3.62), but not among dogs exposed to lawns or gardens treated with insecticides alone (OR, 1.62), compared with dogs exposed to untreated lawns. Exposure to lawns or gardens treated with phenoxy herbicides (OR, 4.42) was associated with an increased risk of TCC, compared with exposure to untreated lawns or gardens, but exposure to lawns or gardens treated with nonphenoxy herbicides (OR, 3.49) was not significantly associated with risk of TCC. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that exposure to lawns or gardens treated with herbicides was associated with an increased risk of TCC in Scottish Terriers. Until additional studies are performed to prove or disprove a cause-and-effect relationship, owners of Scottish Terriers should minimize their dogs' access to lawns or gardens treated with phenoxy herbicides.     

Topical flea and tick pesticides and the risk of transitional cell carcinoma of the urinary bladder in Scottish Terriers

OBJECTIVE: To determine whether use of topical flea and tick products increases the risk of transitional cell carcinoma (TCC) of the urinary bladder in Scottish Terriers. DESIGN: Case-control study. ANIMALS: 87 adult Scottish Terriers with TCC (cases) and 83 adult Scottish Terriers with other health-related conditions (controls). PROCEDURE: Owners of study dogs were recruited through private veterinary practices and the Scottish Terrier Club of America. History of exposure to flea and tick products 1 year prior to diagnosis of TCC for case dogs and during a comparable period for control dogs was obtained through a questionnaire. Risk of TCC associated with exposure to flea and tick products was determined by means of univariate and multiple logistic regression analysis. RESULTS: After adjustment for host factors, Scottish Terriers treated with topical spot-on flea and tick products containing fipronil or imidacloprid did not have an increased risk of TCC, compared with Scottish Terriers that had never been exposed to any flea and tick products. The risk of TCC associated with use of older topical flea and tick products such as shampoos, dips, powders, sprays, and collars could not be evaluated because of the low number of owners in the study population that had used such products. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of topical spot-on flea and tick products does not increase the risk of TCC in Scottish Terriers.     

Epidemiologic study of relationships between consumption of commercial canned food and risk of hyperthyroidism in cats

OBJECTIVE: To determine whether the increasing prevalence of feline hyperthyroidism is the result of aging of the cat population and whether consumption of canned foods at various times throughout life is associated with increased risk of hyperthyroidism. DESIGN: Retrospective and case-control studies. STUDY POPULATION: Medical records of 169,576 cats, including 3,570 cats with hyperthyroidism, evaluated at 9 veterinary school hospitals during a 20-year period, and 109 cats with hyperthyroidism (cases) and 173 cats without hyperthyroidism (controls). PROCEDURE: Age-adjusted hospital prevalence of hyperthyroidism was calculated by use of Veterinary Medical Database records. On the basis of owners' questionnaire responses, logistic regression was used to evaluate associations between consumption of canned food and development of hyperthyroidism. RESULTS: Age-specific hospital prevalence of feline hyperthyroidism increased significantly from 1978 to 1997. Overall, consumption of pop-top canned (vs dry) food at various times throughout life and each additional year of age were associated with greater risk of developing hyperthyroidism. In female cats, increased risk was associated with consumption of food packaged in pop-top cans or in combinations of pop-top and non-pop-top cans. In male cats, increased risk was associated with consumption of food packaged in pop-top cans and age. CONCLUSIONS AND CLINICAL RELEVANCE: These findings suggest that the increasing prevalence of feline hyperthyroidism is not solely the result of aging of the cat population and that canned foods may play a role.     

Development of a Staphylococcus aureus vaccine against mastitis in dairy cows. II. Field trial

A recently described new Staphylococcus aureus vaccine "MASTIVAC I" (Patent no. PTC/IL98/00627) against S. aureus udder infection elicited protection against experimentally induced infection in cows. In the present paper we describe a large-scale vaccination field trial. A total of 452 Israeli Holstein heifers were included in the study over two consecutive years. Approximately half of the heifers (228) were vaccinated while the others (224) served as a control group. Antibody response was detected in all vaccinated animals 4-5 weeks post-primary immunization and it was sustained throughout the experimental period (300-330 days). S. aureus infection could be detected in only 3 out of 228 animals (1.3%) in the vaccinated group and in 6 out of 224 (2.7%) in the control group. These numbers were too low to be statistically evaluated. However, when somatic cell counts (SCC) and milk yields were considered, a significant difference was found between the two groups, namely, the vaccinated cows in first and second lactation had 42 and 54%, respectively, lower SCCs and milk yields 0.5 kg per day higher than the non-vaccinated control cows. These results suggest that the new vaccine elicits a non-specific health improvement of the udder in addition to specific protection against S. aureus.     

Evaluation of the effect of dietary vegetable consumption on reducing risk of transitional cell carcinoma of the urinary bladder in Scottish Terriers

OBJECTIVE: To evaluate the effects of vegetable consumption and vitamin supplementation on the risk of developing transitional cell carcinoma (TCC) of the urinary bladder in Scottish Terriers. DESIGN: Case-control study. ANIMALS: 92 adult Scottish Terriers with TCC (cases) and 83 Scottish Terriers with other conditions (controls). PROCEDURE: Owners of dogs with TCC completed a questionnaire regarding their dogs' diet and intake of vitamin supplements in the year prior to diagnosis of TCC; owners of control dogs completed the questionnaire for a comparable time period. The risk (odds ratio [OR]) of developing TCC associated with diet and vitamin supplementation was determined by use of logistic regression. RESULTS: After adjustment for age, weight, neuter status, and coat color, there was an inverse association between consumption of vegetables at least 3 times/wk (OR, 0.30; 95% confidence interval [CI], 0.15 to 0.62) and risk of developing TCC. For individual vegetable types, the risk of developing TCC was inversely associated with consumption of green leafy vegetables (OR, 0.12; 95% CI, 0.01 to 0.97) and yellow-orange vegetables (OR, 0.31; 95% CI, 0.14 to 0.70). Consumption of cruciferous vegetables was not significantly associated with a similar reduction in risk of developing TCC (OR, 0.22; CI, 0.04 to 1.11). The power of the study to detect a 50% reduction in TCC risk associated with daily vitamin supplementation was considered low (25%). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that consumption of certain vegetables may prevent or slow the development of TCC in Scottish Terriers.     

Adverse events diagnosed within three days of vaccine administration in dogs

OBJECTIVE: To determine incidence rates and potential risk factors for vaccine-associated adverse events (VAAEs) diagnosed within 3 days of administration in dogs. DESIGN: Retrospective cohort study. ANIMALS: 1,226,159 dogs vaccinated at 360 veterinary hospitals. 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 < or = 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.     

Systemic and local immune response of cows to intramammary infection with Staphylococcus aureus

The association between Staphylococcus aureus chronic mammary gland infection and the resulting immune response expressed by the production of specific IgG and IgA antibodies in blood and milk was studied in Israeli Holstein cows. Specific antibodies of the IgG class were detected in sera of 82.6 per cent of the cows chronically infected by S aureus, while in 17.4 per cent no such antibodies could be detected. Specific IgG antibodies to S aureus were neither detected in sera of cows free of mammary infection nor in those infected with different coagulase-negative staphylococci (CNS) such as S intermedius, S chromogenes or S haemolyticus. In milk, specific IgG antibodies to S aureus were detected only in cows with positive serology. The end point dilutions in the milk were 5 to 30 per cent of that of blood from the same cow. No significant difference in IgG titres was found in the same cow if the quarter was infected with S aureus or not. Specific antibodies to S aureus of the IgA class could not be detected in the sera of any of the cows included in this study. In milk, a specific IgA antibody was detected only in the samples from the S aureus infected quarters in which S aureus was isolated at the time of the experiment. In the same cow, quarters infected by S aureus were found to have a significantly higher IgA titre (P < 0.0001) than that of the non-infected ones.     

Prevalence of and risk factors for leptospirosis among dogs in the United States and Canada: 677 cases (1970-1998)

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 disease. DESIGN: Retrospective study. 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, and breed. 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.