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- Author or Editor: David D. Smith x
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Objective—To identify, by means of 24-hour ambulatory electrocardiography, electrocardiographic abnormalities in overtly healthy Doberman Pinschers in which results of echocardiography were abnormal.
Design—Clinical case series.
Animals—56 (35 male, 21 female) overtly healthy Doberman Pinschers with echocardiographic evidence of cardiomyopathy on initial examination that subsequently died of cardiomyopathy.
Procedure—Twenty-four-hour ambulatory electrocardiographic (Holter) recordings obtained at the time of initial examination were reviewed. For all dogs, scan quality was > 90%.
Results—Initial Holter recordings of all 56 dogs contained ventricular premature contractions (VPC). Thirty-six (65%) dogs had > 1,000 VPC/24 h, 17 (31%) had > 5,000 VPC/24 h, and 11 (19%) had > 10,000 VPC/24 h. Fifty-four (96%) dogs had couplets of VPC, 37 (66%) had triplets of VPC, and 36 (64%) had episodes of nonsustained (< 30 seconds) ventricular tachycardia. Number of VPC/24 h during the initial Holter recordings was positively correlated with numbers of couplets and triplets of VPC and number of ventricular escape beats and negatively correlated with left ventricular fractional shortening. Twentyeight dogs died suddenly prior to the putative onset of congestive heart failure.
Conclusions and Clinical Relevance—Results suggested that along with echocardiography, 24-hour ambulatory electrocardiography can be used to help identify overtly healthy Doberman Pinschers with cardiomyopathy. (J Am Vet Med Assoc 2000;217: 1328–1332)
Objective—To characterize ambulatory electrocardiographic results of overtly healthy Doberman Pinschers and determine associations between those results and development of dilated cardiomyopathy.
Animals—114 (58 male, 56 female) overtly healthy Doberman Pinschers without echocardiographic evidence of cardiac disease on initial examination.
Procedure—Echocardiograms and 24-hour ambulatory electrocardiograms (Holter recordings) were obtained initially and at variable intervals. The status (live vs dead) of all dogs was known at least 2 years and as long as 10 years after initial examination (mean [± SD] follow-up time, 4.33 ± 1.84 years). Associations between development of dilated cardiomyopathy and number of ventricular premature contractions (VPC), age, and sex were determined.
Results—55 dogs (48%) did not have VPC on initial Holter recordings, and only 8 dogs had > 50 VPC/24 hours. The likelihood that a dog would have VPC was associated with increasing age and being male. At least 1 VPC/24 hours, and in particular, > 50 VPC/24 hours or ≥ 1 couplet or triplet of VPC/24 hours, were predictive of subsequent development of dilated cardiomyopathy. Fifty-four dogs (47%) developed dilated cardiomyopathy; 12 were still alive at the end of the study, and 42 had died. Twenty-five of these 42 dogs died after the onset of congestive heart failure (CHF), 15 died suddenly before the onset of overt CHF, and 2 died of noncardiac causes. More males developed dilated cardiomyopathy than females, and dogs that died suddenly were approximately 1 year younger than those that developed CHF.
Conclusions and Clinical Relevance—Results of high-quality Holter recordings may be used to identify overtly healthy Doberman Pinschers that are at a high risk for dilated cardiomyopathy. ( J Am Vet Med Assoc 2000;216:34–39)
Objective—To determine whether treatment with selamectin would reduce clinical signs of flea allergy dermatitis (FAD) in dogs and cats housed in flea-infested environments.
Design—Randomized controlled trial.
Animals—22 dogs and 17 cats confirmed to have FAD.
Procedure—Animals were housed in carpeted pens capable of supporting the flea life cycle and infested with 100 fleas (Ctenocephalides felis) on days –13 and –2 and on alternate weeks with 10 to 20 fleas. On day 0, 11 dogs and 8 cats were treated with selamectin (6 mg/kg [2.7 mg/lb]). Dogs were retreated on day 30; cats were retreated on days 30 and 60. All animals were examined periodically for clinical signs of FAD. Flea counts were conducted at weekly intervals.
Results—Throughout the study, geometric mean flea counts exceeded 100 for control animals and were ≤ 11 for selamectin-treated animals. Selamectin-treated cats had significant improvements in the severity of miliary lesions and scaling or crusting on days 42 and 84, compared with conditions on day –8, and in severity of excoriation on day 42. In contrast, control cats did not have any significant improvements in any of the clinical signs of FAD. Selamectin-treated dogs had significant improvements in all clinical signs on days 28 and 61, but in control dogs, severity of clinical signs of FAD was not significantly different from baseline severity at any time.
Conclusions and Clinical Relevance—Results suggest that topical administration of selamectin, even without the use of supplementary environmental control measures and with minimal therapeutic intervention, can reduce the severity of clinical signs of FAD in dogs and cats. (J Am Vet Med Assoc 2003;223:639–644)
Objective—To identify herd-level risk factors for bovine respiratory disease (BRD) in nursing beef calves.
Design—Population-based cross-sectional survey.
Sample—2,600 US cow-calf producers in 3 Eastern and 3 Plains states.
Procedures—The associations of herd characteristics with BRD detection in calves and cumulative BRD treatment incidence were determined.
Results—459 (177%) surveys were returned and met the inclusion criteria; 48% and 52% of these surveys were completed by producers in Plains and Eastern states, respectively. Mean (95% confidence interval) number of animals in herds in Plains and Eastern states were 102 (77 to 126) and 48 (40 to 56), respectively. Bovine respiratory disease had been detected in ≥ 1 calf in 21% of operations; ≥ 1 calf was treated for BRD and ≥ 1 calf died because of BRD in 89.2% and 46.4% of operations in which calf BRD was detected, respectively. Detection of BRD in calves was significantly associated with large herd size, detection of BRD in cows, and diarrhea in calves. Calving season length was associated with BRD in calves in Plains states but not Eastern states. Cumulative incidence of BRD treatment was negatively associated with large herd size and examination of cows to detect pregnancy and positively associated with calving during the winter, introduction of calves from an outside source, offering supplemental feed to calves, and use of an estrous cycle synchronization program for cows.
Conclusions and Clinical Relevance—Results of this study indicated factors associated with calf BRD risk; modification of these factors could potentially decrease the incidence of BRD in nursing calves.
Objective—To test the life-sparing and therapeutic effect of a parenterally administered virus-specific antiviral phosphorodiamidate morpholino oligomer (PMO) for treating kittens during outbreaks of severe viral disease.
Animals—112 kittens of various sex and age in 4 trials involving 3 outbreaks of naturally developing caliciviral disease.
Procedures—Each trial provided an opportunity to investigate the disease. A calicivirus isolated from the liver of a cat that died with hemorrhage and hepatitis was sequenced, and a PMO that had sequence specificity complementary to a 5' region was synthesized. In vitro efficacy of the PMO was tested against the isolate, followed by 3 trials in outbreaks of severe caliciviral disease. The PMO was administered starting on day 1 of disease onset (0.7 to 5.0 mg/kg, SC, q 24 h) and continuing for up to 7 days. Survival time, clinical recovery, and caliciviral shedding were compared by use of various antiviral dosages. In a fourth trial involving nonfatal disease, a control treatment was administered for comparison.
Results—In vitro blockage of caliciviral replication by the PMO was dose dependent. In trials 1 to 3 in which survival was the endpoint, 47 of 59 cats receiving PMO survived but only 3 of 31 survived without PMO treatment. Antiviral treatment reduced viral shedding and hastened clinical recovery, as measured by weight gains and clinical condition.
Conclusions and Clinical Relevance—These data provided evidence that virus-specific PMOs were effective in treating kittens with severe Vesivirus disease and suggested a broader application for other viruses and species, including humans.
OBJECTIVE To determine herd-level risk factors for bovine respiratory disease (BRD) in nursing beef calves.
DESIGN Matched case-control study.
SAMPLE 84 cow-calf operations in Nebraska, North Dakota, and South Dakota.
PROCEDURES Case herds were herds that treated at least 5% of the calf crop for BRD prior to weaning. Control herds were herds that treated < 0.5% of the calf crop for BRD prior to weaning. Each case herd was matched with 2 control herds on the basis of veterinary practice and enrollment year. Herd owners or managers were interviewed by telephone, and characteristics and practices associated with case status were determined by multivariable conditional logistic regression.
RESULTS 30 case herds and 54 control herds were evaluated. Increasing herd size, frequent pasture movement for intensive grass management (intensive grazing), and use of estrus-synchronization programs were significantly associated with herd status. The odds of being a case herd for herds with 150 to 499 cows was 7.9 times and that for herds with ≥ 500 cows was 12 times, compared with the odds of being a case herd for herds with < 150 cows. The odds of being a case herd for herds that used intensive grazing was 3.3 times that for herds that did not use intensive grazing. The odds of being a case herd for herds that used an estrus-synchronization program was 4.5 times that for herds that did not use an estrus-synchronization program.
CONCLUSIONS AND CLINICAL RELEVANCE Management practices can be associated with an increase in the BRD incidence in nursing beef calves. Modification of management practices may decrease BRD incidence in nursing calves for herds in which it is a problem.
OBJECTIVE To describe use of whole-genome sequencing (WGS) and evaluate the apparent sensitivity and specificity of antemortem tuberculosis tests during investigation of an unusual outbreak of Mycobacterium bovis infection in a Michigan dairy herd.
DESIGN Bovine tuberculosis (bTB) outbreak investigation.
ANIMALS Cattle, cats, dog, and wildlife.
PROCEDURES All cattle in the index dairy herd were screened for bTB with the caudal fold test (CFT), and cattle ≥ 6 months old were also screened with a γ-interferon (γIFN) assay. The index herd was depopulated along with all barn cats and a dog that were fed unpasteurized milk from the herd. Select isolates from M bovis–infected animals from the index herd and other bTB-affected herds underwent WGS. Wildlife around all affected premises was examined for bTB.
RESULTS No evidence of bTB was found in any wildlife examined. Within the index herd, 53 of 451 (11.8%) cattle and 12 of 21 (57%) cats were confirmed to be infected with M bovis. Prevalence of M bovis–infected cattle was greatest among 4- to 7-month-old calves (16/49 [33%]) followed by adult cows (36/203 [18%]). The apparent sensitivity and specificity were 86.8% and 92.7% for the CFT and 80.4% and 96.5% for the γIFN assay when results for those tests were interpreted separately and 96.1% and 91.7% when results were interpreted in parallel. Results of WGS revealed that M bovis–infected barn cats and cattle from the index herd and 6 beef operations were infected with the same strain of M bovis. Of the 6 bTB-affected beef operations identified during the investigation, 3 were linked to the index herd only by WGS results; there was no record of movement of livestock or waste milk from the index herd to those operations.
CONCLUSIONS AND CLINICAL RELEVANCE Whole-genome sequencing enhanced the epidemiological investigation and should be used in all disease investigations. Performing the CFT and γIFN assay in parallel improved the antemortem ability to detect M bovis–infected animals. Contact with M bovis–infected cattle and contaminated milk were major risk factors for transmission of bTB within and between herds of this outbreak.