Comparison of Thoracic Auscultation,Clinical Score,and Ultrasonography as Indicators of Bovine Respiratory Disease in Preweaned Dairy Calves

Background

The diagnostic tools for bovine respiratory disease diagnosis include clinical inspection, thoracic auscultation, and ultrasonography.

Hypothesis

Thoracic auscultation and clinical examination have limitations in the detection of lung consolidation in dairy calves.

Animals

Prospective cohort of 106 preweaned calves from 13 different dairy herds (10 with a history of active bovine respiratory disease (BRD) in calves and 3 without suspected BRD problems).

Methods

Each preweaned calf was clinically inspected using the Wisconsin calf respiratory scoring chart (CRSC) and treatment history was noted. Systematic thoracic auscultation and ultrasonography then were performed, the latter focusing on lung consolidation. Mortality was recorded over a 30‐day period.

Results

A total of 56 of 106 calves had ultrasonographic evidence of lung consolidation. The sensitivity of thoracic auscultation to detect consolidation was 5.9% (range, 0–16.7%). Only 41.1% (23/33) of calves with consolidated lungs had been treated previously by the producers. When adding CRSC and previous BRD treatment by the producer, sensitivity of detection increased to 71.4% (40/56). The area under the receiver operating characteristics curve was 0.809 (95% CI, 0.721–0.879) for the number of areas within the lungs with consolidation and 0.743 (95% CI, 0.648–0.823) for the maximal depth of consolidation as predictors of death within 1 month after examination. These were not significantly different (P = .06).

Conclusions and Clinical Importance

This study shows that thoracic auscultation is of limited value in diagnosing lung consolidation in calves. Ultrasonographic assessment of the thorax could be a useful tool to assess BRD detection efficiency on dairy farms.     

Evaluation of Digital and Optical Refractometers for Assessing Failure of Transfer of Passive Immunity in Dairy Calves

Background

Failure of transfer of passive immunity (FTPI) is the underlying predisposing risk factor for most early losses in dairy calves. Refractometers, either optical or digital, can be used to assess FTPI as a part of calf health monitoring program on dairy operations.

Objectives

To evaluate the performance of and differences between digital Brix and optical refractometers for assessing FTPI in dairy calves.

Animals

Two hundred Holstein calves from 1 to 11 days of age.

Methods

A cross‐sectional study was designed to measure serum IgG concentration by radial immunodiffusion (RID) assay, digital Brix and optical refractometers. The correlation coefficients (r) between the 2 refractometers were plotted against each other and against the measured IgG concentration from RID. The Se, Sp, and accuracy of digital Brix and optical refractometers for assessing FTPI using previously recommended cut‐offs were calculated. A receiver operating characteristic curve was created and used to identify the optimal cut‐off for this dataset.

Results

The RID IgG concentration was positively correlated with digital Brix (r = 0.79) and optical (r = 0.74) refractometers. The best combination of Se (85.5%), Sp (82.8%), and accuracy (83.5%) of digital Brix refractometer was at 8.3%Brix. For optical refractometer, the best combination of Se (80%), Sp (80.7%), and accuracy (80.5%) was at 5.5 g/dL.

Conclusions and Clinical Importance

Both refractometers exhibited utility in assessing FTPI in dairy calves.     

Evaluation of a Computer‐aided Lung Auscultation System for Diagnosis of Bovine Respiratory Disease in Feedlot Cattle

Background

A computer‐aided lung auscultation (CALA) system was recently developed to diagnose bovine respiratory disease (BRD) in feedlot cattle.

Objectives

To determine, in a case–control study, the level of agreement between CALA and veterinary lung auscultation and to evaluate the sensitivity (Se) and specificity (Sp) of CALA to diagnose BRD in feedlot cattle.

Animals

A total of 561 Angus cross‐steers (initial body weight = 246 ± 45 kg) were observed during the first 50 day after entry to a feedlot.

Methods

Case–control study. Steers with visual signs of BRD identified by pen checkers were examined by a veterinarian, including lung auscultation using a conventional stethoscope and CALA that produced a lung score from 1 (normal) to 5 (chronic). For each steer examined for BRD, 1 apparently healthy steer was selected as control and similarly examined. Agreement between CALA and veterinary auscultation was assessed by kappa statistic. CALA''s Se and Sp were estimated using Bayesian latent class analysis.

Results

Of the 561 steers, 35 were identified with visual signs of BRD and 35 were selected as controls. Comparison of veterinary auscultation and CALA (using a CALA score ≥2 as a cut off) revealed a substantial agreement (kappa = 0.77). Using latent class analysis, CALA had a relatively high Se (92.9%; 95% credible interval [CI] = 0.71–0.99) and Sp (89.6%; 95% CI = 0.64–0.99) for diagnosing BRD compared with pen checking.

Conclusions

CALA had good diagnostic accuracy (albeit with a relatively wide CI). Its use in feedlots could increase the proportion of cattle accurately diagnosed with BRD.     

Thoracic Ultrasonography and Bronchoalveolar Lavage Fluid Analysis in Holstein Calves with Subclinical Lung Lesions

Background

Thoracic ultrasonography (US) and bronchoalveolar lavage fluid (BALF) analysis are antemortem methods used to identify the lung lesions associated with bovine respiratory disease (BRD). Accuracy of US and the cell distributions in BALF have not been characterized in calves with subclinical disease.

Objectives

To evaluate the accuracy of US and BALF and describe BALF characteristics in calves with subclinical lung lesions.

Animals

Twenty‐five Holstein calves, 1–12 weeks old.

Methods

In this prospective study, calves with low respiratory scores underwent US, BALF and postmortem examination (normal US, n = 5; comet‐tails, n = 5; consolidation, n = 15). Bronchoalveolar lavage fluid was collected and analyzed for total and differential cell counts. Lung lesions were assessed by gross and histopathologic examination. Data were analyzed using nonparametric methods and relative risk analysis. The accuracy of US and BALF were estimated relative to postmortem examination.

Results

The sensitivity and specificity of US for detecting lung lesions was 94% (95% CI, 69–100%) and 100% (95% CI, 64–100%), respectively. A cut‐point of ≥4% BALF neutrophils was associated with the highest BALF sensitivity and specificity, 81% (95% CI, 56–94%) and 75% (95% CI, 36–95%). The presence of consolidation on US increased the risk of having a BALF neutrophil proportion ≥4% (RR, 3.9; 95% CI, 1.13–13.45; P = .003).

Conclusions and Clinical Importance

Ultrasonography accurately detects lung lesions in calves with subclinical disease. Clinicians should use a cut‐point of ≥4% BALF neutrophils to diagnose subclinical respiratory disease.     

Quantitative Physicochemical Analysis of Acid‐Base Balance and Clinical Utility of Anion Gap and Strong Ion Gap in 806 Neonatal Calves with Diarrhea

Background

Acid‐base abnormalities in neonatal diarrheic calves can be assessed by using the Henderson‐Hasselbalch equation or the simplified strong ion approach which use the anion gap (AG) or the strong ion gap (SIG) to quantify the concentration of unmeasured strong anions such as d‐lactate.

Hypothesis/Objectives

To determine and compare the clinical utility of AG and SIG in quantifying the unmeasured strong anion charge in neonatal diarrheic calves, and to examine the associations between biochemical findings and acid‐base variables by using the simplified strong ion approach. We hypothesized that the SIG provides a more accurate prediction of unmeasured strong anions than the AG.

Animals

Eight hundred and six neonatal diarrheic calves admitted to a veterinary teaching hospital.

Methods

Retrospective study utilizing clinicopathologic findings extracted from medical records.

Results

Hyperphosphatemia was an important predictor of venous blood pH. Serum inorganic phosphorus and plasma d‐lactate concentrations accounted for 58% of the variation in venous blood pH and 77% of the variation in AG and SIG. Plasma d‐ and total lactate concentrations were slightly better correlated with SIG (r _s  = −0.69; −0.78) than to AG (r _s = 0.63; 0.74).

Conclusions and Clinical Importance

Strong ion gap is slightly better at quantifying the unmeasured strong anion concentration in neonatal diarrheic calves than AG. Phosphorus concentrations should be included as part of the calculation of A _tot when applying the simplified strong ion approach to acid‐base balance to critically ill animals with hyperphosphatemia.     

Incidence,Timing, and Risk Factors of Azathioprine Hepatotoxicosis in Dogs

Background

The use of azathioprine (AZA) in dogs is limited by the development of hepatotoxicosis and cytopenias.

Hypothesis and Objectives

To characterize the observed incidence, timing, and risk factors for AZA hepatotoxicosis in dogs treated clinically, and to determine the relationship between the development of hepatotoxicosis and cytopenias.

Animals

Fifty‐two dogs treated with AZA with clinical and biochemical follow‐up, with a subset of 34 dogs available for determination of changes in liver enzyme activities in serum.

Methods

Retrospective medical record review, from January 2009 through December 2013.

Results

Hepatotoxicosis (as defined by a >2‐fold increase in serum ALT) was observed in 5 of 34 dogs (15%) within a median onset of 14 days (range, 13–22 days). Dogs had a median 9‐fold increase in ALT and 8‐fold increase in ALP, which stabilized or resolved with drug discontinuation or dose reduction. German shepherds were significantly over‐represented (3 of 5 dogs with hepatotoxicosis; P = .0017). Thrombocytopenia or neutropenia were seen in 4 of 48 dogs with CBC follow‐up (8% of dogs), but occurred significantly later in treatment (median onset, 53 days; range 45–196 days) compared to hepatotoxicosis (P = .016).

Conclusions and Clinical Importance

These results support the routine monitoring of liver enzymes during the first 1–4 weeks of AZA treatment in dogs, with continued monitoring of the CBC. Additional studies are warranted to characterize the apparently higher risk of AZA hepatotoxicosis in German shepherds.     

Clinical Findings and Survival in 56 Sick Neonatal New World Camelids

Background

Information pertaining to clinical presentation and outcome of neonatal New World camelids (NWC) is limited when compared to calves and foals.

Hypothesis

Values of variables at admission and subsequent treatment would predict survival in sick neonatal NWC.

Animals

Fifty‐six client‐owned sick neonatal NWC presented over a 10‐year period to the Purdue University Veterinary Teaching Hospital.

Methods

A retrospective study was performed. Inclusion criteria were NWC less than 30 days of age with complete medical records that presented between 2000 and 2010.

Results

The median age at presentation was 1 day (range 1–20). The most common diagnoses were systemic inflammatory response syndrome (50%), congenital defects (41%), ophthalmic lesions (21%), sepsis (16%), and gastrointestinal diseases (16%). Sixty‐six percent of NWC survived to discharge. Clinicopathologic findings on admission were variable and not specific for disorders. Factors associated with survival were absence of choanal atresia (P = .001, OR: 55.9 [2.5–1,232]), administration of llama plasma (P = .013, OR: 4.9 [1.4–17.7]), and antimicrobial treatment with trimethoprim‐sulfamethoxazole (TMS) (P = .016, OR: 6.5 [1.3–32.2]).

Conclusions and Clinical Importance

The use of antibiotics, particularly TMS, and llama plasma are recommended in sick neonatal NWC. Results from this study could contribute toward defining a NWC‐specific sepsis scoring system.     

Prevalence of Bacteremia in Dairy Cattle with Acute Puerperal Metritis

Background

Acute puerperal metritis (APM) affects 30% of postpartum dairy cattle. Bacteremia negatively impacts survival in cattle with coliform mastitis. However, the prevalence of bacteremia in dairy cattle with APM is unknown.

Hypothesis

Bacteremia is detectable in a large proportion of cattle with APM.

Animals

Seventeen dairy cows with APM and 17 healthy dairy cattle.

Methods

Prospective case‐control study. Cases were identified by daily monitoring of cattle in the first 10 days after calving. Controls were matched to cases by parity and days in milk. Cows were examined at the time of identification of APM. A complete blood count, serum biochemical analysis, and bacteriologic culture of blood and lochial fluid were performed on each animal at the time of diagnosis. The same samples were collected from healthy herdmates of a similar parity and days in milk. Blood culture results and clinicopathologic variables were compared between groups. Conditional logistic regression was used to evaluate factors associated with APM, whereas multivariate logistic regression was used to evaluate factors associated with bacteremia.

Results

Bacteremia occurred in 53% (9/17) of cattle with APM and 53% (8/15) controls. Bacillus spp. was the organism most commonly isolated from the bloodstream in cattle of both groups. Bacteremic cattle in both groups were significantly less likely to have basophils in the peripheral circulation (P = .02) and more likely to have higher serum globulin concentrations (P = .02).

Conclusions and Clinical Importance

Bacteremia is a common occurrence in postpartum dairy cattle. Further study is warranted to investigate the modes by which bacteria colonize the bloodstream in this population of animals and the importance of bacteremia on health and productivity of affected animals.     

Clinical Findings and Prevalence of the Mutation Associated with Primary Ciliary Dyskinesia in Old English Sheepdogs

Background

Primary ciliary dyskinesia (PCD) is generally a recessively inherited disorder characterized by dysfunction of motile cilia. A mutation in a new causative gene (CCDC39) has been identified in the Old English Sheepdog (OES).

Objectives

To describe the clinical findings and the molecular changes of affected dogs and estimate the worldwide prevalence of the mutation in a large cohort of OES.

Animals

578 OES, including 28 affected and 550 clinically healthy dogs.

Methods

This retrospective study reviewed the data of OES diagnosed with PCD and OES tested for the mutation. Clinical data including results of physical examination and further investigations were obtained on 11/28 dogs. CCDC39 expression was assessed by qRT‐PCR and Western blot analysis in affected dogs and healthy dogs. DNA was extracted on 561/578 dogs and a genetic test by Taqman technology was developed to genotype the CCDC39 mutation in these dogs.

Results

Clinical findings were recurrent nasal discharge and cough, pyrexia, leucocytosis, and bronchopneumonia. Ultrastructural defects were characterized by central microtubular abnormalities and decreased number of inner dynein arms (IDAs). Molecular analysis revealed a reduced expression of CCDC39 RNA and an absence of CCDC39 protein in affected dogs compared to healthy dogs. The mutation was more frequent in nonrandomly selected European OES population with a higher proportion of carriers (19%) compared to non‐European dogs (7%).

Conclusion and Clinical Importance

CCDC39 mutation is dispersed in a worldwide population and is responsible for PCD in this breed. Genetic testing might enable control of this disease.     

A Randomized Clinical Trial Evaluating Metabolism of Colostral and Plasma Derived Immunoglobulin G in Jersey Bull Calves

Background

Intravenous plasma administration has been recommended in healthy or sick calves with failure of passive immunity.

Hypothesis

IV administered plasma‐derived immunoglobulin G (IgG) undergoes increased catabolism as reflected by a rapid decrease in serum IgG concentration with an increase in fecal IgG concentrations within 48 h.

Animals

Thirty newborn Jersey calves. Fifteen were fed colostrum (CL group) and 15 were given bovine plasma IV (PL group).

Materials and Methods

Randomized clinical trial. Calves in the CL group were fed 3 L of colostrum once, by oroesophageal tubing. Calves in the PL group were given plasma IV at a dosage of 34 mL/kg. Serum and fecal samples were collected at 0 h, 6 h, 12 h, 48 h, 5 d, and 7 d. Serum and fecal IgG concentrations were determined by radial immunodiffusion.

Results

Calves in the CL group maintained serum IgG concentrations consistent with adequate transfer of immunity (≥1,000 mg/dL) throughout the study period. Calves in the PL group achieved median IgG concentrations of ≥1,000 mg/dL at 6 h but the concentrations were <1,000 mg/dL by 12 h. Calves in the PL group were 5 times more likely to experience mortality compared to the CL group (hazard ratio = 5.01). Fecal IgG concentrations were not different between the 2 groups during the first 48 h (P > .05).

Conclusions and Clinical Importance

Catabolism of plasma derived IgG occurs rapidly during the first 12 h after transfusion. Fecal excretion did not explain the fate of the plasma derived IgG.     

Idiopathic Epilepsy in the Italian Spinone in the United Kingdom: Prevalence,Clinical Characteristics,and Predictors of Survival and Seizure Remission

Background

There is lack of data on idiopathic epilepsy (IE) in the Italian Spinone (IS).

Objectives

To estimate the prevalence of IE in the IS in the United Kingdom (UK) and to investigate predictors of survival and seizure remission.

Animals

The target population consisted of 3331 IS born between 2000 and 2011 and registered with the UK Kennel Club (KC). The owners of 1192 dogs returned phase I questionnaire. Sixty‐three IS had IE.

Methods

Population survey. The owners of all UK KC‐registered IS were invited to complete the phase I questionnaire. Information from the phase I questionnaire and veterinary medical records was used to identify IS with IE and obtain data on treatment and survival. Additional information was obtained from owners of epileptic IS who completed the phase II questionnaire.

Results

The prevalence of IE in the IS in the UK was estimated as 5.3% (95% CI, 4.03–6.57%). Survival time was significantly shorter in IS euthanized because of poorly controlled IE compared with epileptic IS that died of unrelated disorders (P = 0.001). Survival was significantly longer in IS with no cluster seizures (CS) (P = 0.040) and in IS in which antiepileptic medication was initiated after the second seizure rather than after ≥3 seizures (P = 0.044). Seizure remission occurred only in 3 IS.

Conclusions and Clinical Importance

The prevalence of IE in IS (5.3%) is higher than in dogs (0.6%) in the UK. Idiopathic epilepsy in IS has a severe phenotype. Antiepileptic medication initiation after the second seizure and aggressive treatment of CS may improve survival.     

Symmetric Dimethylarginine Assay Validation,Stability, and Evaluation as a Marker for the Early Detection of Chronic Kidney Disease in Dogs

Background

Symmetric dimethylarginine (SDMA) is a small molecule formed by methylation of arginine, and released into blood during protein degradation. SDMA is primarily eliminated by renal excretion and is a promising endogenous marker of glomerular filtration rate (GFR).

Objectives

To validate an assay for SDMA measurement, determine stability of SDMA in blood, and compare SDMA with serum creatinine concentration (sCr) and GFR for early detection of decreasing kidney function in dogs with chronic kidney disease (CKD).

Animals

Eight male dogs affected with X‐linked hereditary nephropathy and 4 unaffected male littermates.

Methods

Prospective study validating SDMA measurement using liquid chromatography‐mass spectrometry, assessing stability of SDMA in serum and plasma, and serially determining sCr, SDMA, and GFR (using iohexol clearance) in dogs during progression from preclinical disease to end‐stage renal failure. Correlations were determined using linear regression. Timepoints at which sCr, SDMA, and GFR identified decreased renal function were compared using defined cutoffs, trending in an individual dog, and comparison with unaffected littermates.

Results

Symmetric dimethylarginine was highly stable in serum and plasma, and the assay demonstrated excellent analytical performance. In unaffected dogs, SDMA remained unchanged whereas in affected dogs, SDMA increased during disease progression, correlating strongly with an increase in sCr (r = 0.95) and decrease in GFR (r = −0.95). Although trending improved sCr''s sensitivity, SDMA identified, on average, <20% decrease in GFR, which was earlier than sCr using any comparison method.

Conclusions and Clinical Importance

Symmetric dimethylarginine is useful for both early identification and monitoring of decreased renal function in dogs with CKD.     

Multiple Hypersensitivities Including Recurrent Airway Obstruction,Insect Bite Hypersensitivity,and Urticaria in 2 Warmblood Horse Populations

Background

Multiple hypersensitivities (MHS) have been described in humans, cats, and dogs, but not horses.

Hypotheses

Horses suffering from recurrent airway obstruction (RAO), insect bite hypersensitivity (IBH), or urticaria (URT) will have an increased risk of also being affected by another one of these hypersensitivities. This predisposition for MHS also will be associated with decreased shedding of strongylid eggs in feces and with a single nucleotide polymorphism (SNP BIEC2‐224511), previously shown to be associated with RAO.

Animals

The first population (P1) included 119 randomly sampled horses representative of the Swiss sporthorse population; the replication population (P2) included 210 RAO‐affected Warmblood horses and 264 RAO‐unaffected controls. All horses were Warmbloods, 14 years or older.

Methods

Associations between disease phenotypes (RAO, IBH, URT, MHS) fecal egg counts, the SNP BIEC2‐224511 as well as management and environmental factors were investigated.

Results

In P1, RAO‐affected horses had a 13.1 times higher odds ratio (OR) of also suffering from IBH (P = .004). In P2, the respective OR was 7.4 (P = .002) and IBH‐affected horses also showed a 7.1 times increased OR of concomitantly suffering from URT (P < .001). IBH, URT, and MHS phenotypes were significantly associated with the absence of nematode eggs in the feces.

Conclusions and Clinical Importance

This is the first report of MHS in horses. Specifically, an increased risk for IBH should be expected in RAO‐affected horses.     

Abdominal Ultrasound Examination Findings in 534 Hyperthyroid Cats Referred for Radioiodine Treatment Between 2007–2010

Background

The prevalence of concurrent disease in hyperthyroid cats is unknown.

Objectives

To identify the prevalence of concurrent intra‐abdominal disease using abdominal ultrasound examination (AUS) in hyperthyroid cats referred for radioactive iodine treatment (RIT) and to determine whether the requirement for pretreatment AUS is justified.

Animals

Five hundred and thirty‐four client‐owned cats diagnosed with hyperthyroidism and referred for RIT.

Methods

Retrospective study. Age, breed, sex, body weight, clinical signs, total serum T4 concentration, blood urea nitrogen (BUN) concentration, serum creatinine concentration, urine specific gravity (USG), AUS results, and biopsy or cytology results, or both (if obtained) were collected from the medical records.

Results

The prevalence of concurrent disease identified using AUS in hyperthyroid cats referred for RIT was 36.1%; 22.8% of the cats in the study had renal disease and 2.4% had confirmed neoplasia. Significant differences in median USG (P value 0.032) and median BUN (P value 0.028) were found between cats that had abnormal kidneys on AUS compared to those with normal‐appearing kidneys. Only 2.2% of the cats were not treated with RIT as a result of changes identified on AUS and subsequently obtained cytology or biopsy results.

Conclusions and Clinical Importance

The results indicate that pretreatment AUS in hyperthyroid cats referred for RIT is unnecessary in most patients.     

Relationship between Plasma Fibroblast Growth Factor‐23 Concentration and Survival Time in Cats with Chronic Kidney Disease

Background

Fibroblast growth factor‐23 (FGF‐23) and parathyroid hormone (PTH) are commonly increased in cats with azotemic chronic kidney disease (CKD). Both are predictors of survival time in human patients, but these relationships have not previously been examined in the cat.

Objectives

To investigate the relationship between plasma FGF‐23 and PTH concentrations at diagnosis of CKD in cats with survival time and with disease progression over 12 months.

Animals

214 azotemic, client‐owned cats (≥9 years).

Methods

Retrospective study: Biochemical and urinary variables at diagnosis of azotemic CKD, including plasma FGF‐23 and PTH concentrations were assessed as predictors of survival time (all‐cause mortality) using Cox regression, and as predictors of CKD progression over 12 months using logistic regression.

Results

In the final multivariable Cox regression model, survival was negatively associated with plasma creatinine (P = .002) and FGF‐23 concentrations (P = .014), urine protein‐to‐creatinine ratio (P < .001) and age (P < .001). Survival was positively associated with PCV (P = .004). In the final multivariable logistic regression model, independent predictors of CKD progression included logFGF‐23 and age. Neither plasma phosphate nor PTH was found to be an independent predictor of survival time or of CKD progression.

Conclusions and Clinical Importance

Plasma FGF‐23 concentration is a novel prognostic indicator in cats with CKD, independent of other factors including plasma creatinine and phosphate concentrations. Further work is required to assess if FGF‐23 contributes directly to CKD progression, but regardless these findings may make FGF‐23 a useful biomarker for predicting poorer outcomes in cats with CKD.     

Sudden Death Associated with QT Interval Prolongation and KCNQ1 Gene Mutation in a Family of English Springer Spaniels

Background

A 5‐year‐old, healthy English Springer Spaniel died suddenly 4 months after delivering a litter of 7 puppies. Within 4 months of the dam''s death, 3 offspring also died suddenly.

Hypothesis

Abnormal cardiac repolarization, caused by an inherited long QT syndrome, is thought to be responsible for arrhythmias leading to sudden death in this family.

Animals

Four remaining dogs from the affected litter and 11 related dogs.

Methods

Physical examination and resting ECG were done on the littermates and 9 related dogs. Additional tests on some or all littermates included echocardiogram with Doppler, Holter monitoring, and routine serum biochemistry. Blood for DNA sequencing was obtained from all 15 dogs.

Results

Three of 4 littermates examined, but no other dogs, had prolonged QT intervals with unique T‐wave morphology. DNA sequencing of the KCNQ1 gene identified a heterozygous single base pair mutation, unique to these 3 dogs, which changes a conserved amino acid from threonine to lysine and is predicted to change protein structure.

Conclusions and Clinical Importance

This family represents the first documentation in dogs of spontaneous familial QT prolongation, which was associated with a KCNQ1 gene mutation and sudden death. Although the final rhythm could not be documented in these dogs, their phenotypic manifestations of QT interval prolongation and abnormal ECG restitution suggested increased risk for sudden arrhythmic death. The KCNQ1 gene mutation identified is speculated to impair the cardiac repolarizing current I _Ks, similar to KCNQ1 mutations causing long QT syndrome 1 in humans.     

Cognitive Function,Progression of Age‐related Behavioral Changes,Biomarkers, and Survival in Dogs More Than 8 Years Old

Background

Canine cognitive dysfunction (CCD) is an age‐dependent neurodegenerative condition dominated by changes in behavioral patterns. Cohort studies investigating cognitive status in dogs are lacking.

Objectives

To investigate cognitive function, progression of age‐related behavioral changes, survival, and possible biomarkers of CCD in aged dogs.

Animals

Fifty‐one dogs >8 years old; 21 with no cognitive deficits, 17 with mild cognitive impairments (MCI) and 13 with CCD.

Methods

Longitudinal study. Recruitment period of 12 months and an observational period of 24 months including a baseline and 3 planned subsequent assessments. Cognitive status was determined using validated questionnaires. Plasma Aβ‐peptides were quantified using commercial ELISA assays and cytokines by a validated immunoassay.

Results

Signs characterizing dogs with CCD were aimless wandering, staring into space, avoid getting patted, difficulty finding dropped food and anxiety. Thirty‐three percent of dogs with a normal cognitive status progressed to MCI and 22% classified as MCI progressed to CCD during the study period. For 6 dogs diagnosed with CCD, signs of cognitive dysfunction increased with time. A diagnosis of CCD did not affect survival. The level of plasma Aβ₄₂ was significantly increased (P < .05) in the CCD group (92.8 ± 24.0 pg/mL) compared to the MCI (77.0 ± 12.3 pg/mL) and normal group (74.9 ± 10.0 pg/mL), but no significant differences in concentrations of systemic inflammatory markers were detected.

Conclusions

Canine cognitive dysfunction is a progressive disorder with an individual variability in the rate of cognitive decline and clinical signs. Plasma Aβ₄₂ seems to be an interesting plasma biomarker of CCD.     

A Homozygous KCNJ10 Mutation in Jack Russell Terriers and Related Breeds with Spinocerebellar Ataxia with Myokymia,Seizures, or Both

Background

Juvenile‐onset spinocerebellar ataxia has been recognized in Jack Russell Terriers and related Russell group terriers (RGTs) for over 40 years. Ataxia occurs with varying combinations of myokymia, seizures, and other signs of neurologic disease. More than 1 form of the disease has been suspected.

Hypothesis/Objectives

The objective was to identify the mutation causing the spinocerebellar ataxia associated with myokymia, seizures, or both and distinguish the phenotype from other ataxias in the RGTs.

Animals

DNA samples from 16 RGTs with spinocerebellar ataxia beginning from 2 to 12 months of age, 640 control RGTs, and 383 dogs from 144 other breeds along with the medical records of affected dogs were studied.

Methods

This case‐control study compared the frequencies of a KCNJ10 allele in RGTs with spinocerebellar ataxia versus control RGTs. This allele was identified in a whole‐genome sequence of a single RGT with spinocerebellar ataxia and myokymia by comparison to whole‐genome sequences from 81 other canids that were normal or had other diseases.

Results

A missense mutation in the gene coding for the inwardly rectifying potassium channel Kir4.1 (KCNJ10:c.627C>G) was significantly (P < .001) associated with the disease. Dogs homozygous for the mutant allele all had spinocerebellar ataxia with varying combinations of myokymia and seizures.

Conclusions and Clinical Importance

Identification of the KCNJ10 mutation in dogs with spinocerebellar ataxia with myokymia, seizures, or both clarifies the multiple forms of ataxia seen in these breeds and provides a DNA test to identify carriers.     

Clinical Features and Magnetic Resonance Imaging Findings in 7 Dogs with Central Nervous System Aspergillosis

Background

Systemic aspergillosis is a manifestation of Aspergillus sp. infection that can result in central nervous system (CNS) involvement with marked alterations in CNS function. Information regarding the clinical presentation and magnetic resonance imaging (MRI) findings in cases of aspergillosis with CNS involvement is lacking, resulting in a need for better understanding of this disease.

Hypothesis/Objectives

The primary objectives were to describe the clinical features and MRI findings in dogs with CNS aspergillosis. The secondary objectives were to describe clinicopathologic findings and case outcome.

Animals

Seven dogs with CNS aspergillosis.

Methods

Archived records from 6 institutions were reviewed to identify cases with MRI of CNS aspergillosis confirmed with serum galactomannan enzyme immunoassay (EIA) testing, culture, or supported by histopathology. Signalment, clinical, MRI, clinicopathologic, histopathologic, and microbiologic findings were recorded and evaluated.

Results

Aspergillosis of the CNS was identified in 7 dogs from 3 institutions. The median age was 3 years and six were German Shepherd dogs. Five dogs had signs of vestibular dysfunction as a component of multifocal neurological abnormalities. The MRI findings ranged from normal to abnormal, including hemorrhagic infarction and mass lesions.

Conclusions and Clinical Importance

Until now, all reported MRI findings in dogs with CNS aspergillosis have been abnormal. We document that CNS aspergillosis in dogs, particularly German Shepherd dogs, can be suspected based on neurologic signs, whether MRI findings are normal or abnormal. Confirmatory testing with galactomannan EIA, urine, cerebrospinal fluid (CSF) or tissue culture should be performed in cases where aspergillosis is a differential diagnosis.