Jørgen Koch

Canine pulmonary angiostrongylosis: an update.

Canine pulmonary angiostrongylosis is an emerging snail-borne disease causing verminous pneumonia and coagulopathy in dogs. The parasite is found in Europe, North and South America and Africa, covering tropical, subtropical and temperate regions. Its distribution has been characterised by isolated endemic foci, with only sporadic occurrences outside these areas. In the last two decades, the literature has been dominated by several case reports and small case series describing sporadic disease in old or new endemic areas. Case reports and experimental studies with high doses of infective third stage larvae may not reflect what happens under field conditions. There is insufficient understanding of the spread of infection and the dynamic consequences of this parasite in the canine population. This review discusses the biology, epidemiology, clinical aspects and management of canine pulmonary angiostrongylosis.

Heart rate variability in young, clinically healthy Dachshunds: influence of sex, mitral valve prolapse status, sampling period and time of day.

OBJECTIVE This study investigatest the influence of sampling period duration, time of day, age, sex, body weight and degree of mitral valve prolapse (MVP) on various measures of heart rate variability (HRV) in the dog. The correlations between the HRV parameters were also investigated. BACKGROUND Holter recording is increasingly being used in dogs but method studies are sparse. Previous studies suggest that canine MVP is related to a high vagal tone. METHODS Twenty-four hour ambulatory electrocardiographic recording (Holter recording) was performed on 24 Dachshunds (11 males and 13 females). All dogs were between 2 and 6 years of age and without heart murmurs. RESULTS The majority of the HRV parameters depended on the duration of the sampling period and they generally exhibited circadian variation. Higher values in males than in females were found for several parameters, especially low frequency power (LF) during 24 hour recording (P = 0.0002). Although a number of HRV parameters correlated positively with MVP severity and negatively with age, the influence of these two factors was not clear and consistent in all sampling periods. The degree of MVP related to the number of episodes of supraventrucular tachycardia occuring during the day. Generally, a large inter-individual variation was found with regard to the HRV parameters and the correlations between the parameters were weaker than correlations reported in humans. Two manually measured ECG parameter related to vagal tone correlated strongly with 2 out of 3 vagal indexes derived from the HRV analysis. CONCLUSION HRV parameters are influenced especially by sex and sampling period duration, but also by age and MVP status in young, clinically healthy Dachshunds.

Prevalence of hypertrophic cardiomyopathy in a cohort of British Shorthair cats in Denmark.

BACKGROUND Familial hypertrophic cardiomyopathy (HCM) has been described previously in British Shorthair cats (BSH), but until now, no reports have been published describing the prevalence of the disease within this breed. OBJECTIVES The aim of this study was to assess the prevalence of HCM in a large cohort of BSH and to evaluate the effect of sex, weight, and increasing age as potential risk factors for this disease. ANIMALS Three hundred and twenty-nine BSH presented for routine HCM screening during a 4-year period. METHODS Prospective cross-sectional study in which all cats were screened for HCM by conventional echocardiography. RESULTS A total of 329 cats were examined, 214 females and 115 males, with a median age of 2.3 years (range, 0.8-14.1). Twenty-eight cats (8.5%) were classified as HCM-positive, 14 (4.3%) as equivocal, 282 (85.7%) as HCM-negative, and 5 (2.1%) were diagnosed with other cardiac diseases. The median age for diagnosis of HCM was 2.7 years (range, 0.9-14.1). Male cats had a significantly higher occurrence of HCM (20.4%) compared with the females (2.1%) corresponding to an odds ratio of 7.89 (95 % CI, 2.54-28.08) for males versus females adjusted for age and weight (P < .001). CONCLUSION The BSH in our cohort had a high prevalence of HCM, often of early onset and with a significant male sex predisposition. We strongly recommend echocardiographic screening in this breed, especially cats used for breeding.

Cardiac Troponin I and T as Prognostic Markers in Cats with Hypertrophic Cardiomyopathy

Background Myocardial injury detected by cardiac troponin I and T (cTnI and cTnT) in cardiac disease is associated with increased risk of death in humans and dogs. Hypothesis Presence of myocardial injury predicts long‐term death in cats with hypertrophic cardiomyopathy (HCM), and ongoing myocardial injury reflects change in left ventricular wall thickness over time. Animals Thirty‐six cats with primary HCM. Methods Prospective cohort study. Cats with HCM were included consecutively and examined every 6 months. Echocardiography, ECG, blood pressure, and serum cTnI and cTnT were evaluated at each visit. Cox proportional hazards regression analysis was performed to evaluate prognostic potential of serum troponin concentrations at admission and subsequent examinations. Correlations were used to examine associations between troponin concentrations and cardiac hypertrophy. Results Troponin concentrations at admission were median [range] 0.14 [0.004–1.02] ng/mL for cTnI, and 13 [13–79.5] ng/L for cTnT. Both were prognostic for death (P = .032 and .026) as were the last available concentrations of each (P = .016 and .003). The final cTnT concentration was a significant predictor of death even when adjusting for the admission concentration (P = .043). In a model containing both markers, only cTnT remained significant (P = .043). Left ventricular free wall thickness at end‐diastole (LVFWd) at admission was correlated with cTnI at admission (r = 0.35, P = .035), however no significant correlations (r = 0.2–0.31, P = .074–.26) were found between changes in troponin concentrations and left ventricular thickness over time. Conclusions and Clinical Importance Myocardial injury is part of the pathophysiology leading to disease progression and death. Low sensitivities and specificities prevent outcome prediction in individual cats.

A coprological investigation of gastrointestinal and cardiopulmonary parasites in hunting dogs in Denmark.

A coprological survey was conducted to investigate the prevalence of parasites infecting hunting dogs with no history of recent anthelmintic treatments and with no overt clinical manifestations of cardiopulmonary or gastrointestinal illness. The hunting dogs were recruited from four different areas in Denmark, and fecal samples were obtained in October and November, 2007. For detecting gastrointestinal parasites, samples (N=178) were examined by a commercial flotation kit (Fecalyzer(®) EVSCO, USA). For detection of cardiopulmonary parasites, samples (N=181) were collected on three consecutive days and examined using the Baermann method. Parasites were recovered from 22.1% of the hunting dogs: Angiostrongylus vasorum (2.2%), Toxocara canis (12.4%), Uncinaria stenocephala (7.3%), Taenia spp. (1.7%), Toxascaris leonina (0.6%), Coccidia (0.6%) and unidentified trematode eggs (1.1%). Infection with only one species of parasite was more common (89.5%) than infection with two species (10.5%). A multiple logistic regression model showed that prevalence of intestinal parasites was not influenced by age, gender or breed in adult dogs. There was a significantly higher prevalence of intestinal parasites in the densely populated area of the island Zealand compared with the less populated regions of the peninsular Jutland. The present study reports the first case of A. vasorum in a dog from Jutland. The dog had been visiting the endemic area of western Zealand, suggesting that translocation of sub-clinically infected dogs may contribute to introduction of A. vasorum into non-endemic areas.

Left atrial volume and phasic function in clinically healthy dogs of 12 different breeds.

The left atrium (LA) of the heart is a validated marker of clinical and subclinical cardiovascular disease. Since the LA is a three-dimensional structure, volume-based methods of chamber quantification might be more accurate than linear methods. The aims of this study were to establish the feasibility and reproducibility of biplane two-dimensional echocardiographic LA volume measurements and to provide reference ranges for LA volume and phasic function in adult dogs (n=237) without cardiovascular disease. The study also assessed the effects of bodyweight (BW), breed, sex, age and heart rate (HR) on LA volume and function. The biplane area-length method was used to calculate LA volumes from the left apical four- and two-chamber views. LA volume and function were correlated with body size and there were significant breed differences. For dogs of all sizes and breeds, LA maximal volume had a 95th percentile of 0.92 mL/kg. There was no correlation between age or sex and LA volume or LA reservoir function, but conduit function decreased and booster pump function increased with age. LA volume and function varied with HR. LA size was calculated using the biplane area-length method, with good reproducibility and little inter-observer variability. The reference ranges presented for LA volume and function in healthy dogs could be used to refine the diagnostic criteria for the assessment of LA enlargement and altered function by conventional echocardiography.

Screening for aortic stenosis in the Boxer: Auscultatory, ECG, blood pressure and Doppler echocardiographic findings

OBJECTIVES This study was conducted to estimate the incidence of aortic stenosis (AS) in a group of Boxers evaluated by auscultation, ECG, blood pressure measurement and Doppler-echocardiography. BACKGROUND The Boxer is a breed at significantly increased risk of AS. The prevalence of murmurs and Doppler-echocardiographic findings consistent with AS in this breed is reportedly high. ANIMALS, MATERIALS AND METHODS Eighty-nine Boxers were evaluated by auscultation, and final murmur grade recorded after stress testing. Doppler echocardiography was performed in fifty-five adult Boxers. Electrocardiograms (ECG, n=53), non-invasive blood pressure measurement (n=32), and Holter monitoring (n=24) were performed in selected dogs. Degree of AS was based on the aortic peak flow velocity (Ao PFV). Final Ao PFV was recorded as the highest value obtained after stress testing. AS was defined as an Ao PFV>2m/s on continuous wave Doppler, using the subcostal window. Pressure gradients (Deltap) were calculated using the modified Bernoulli equation (Deltap=4V(2)). Mild AS was defined as Deltap=16-40mmHg, moderate AS Deltap=40-75mmHg, and severe AS Deltap>75mmHg. RESULTS 62% of adult Boxers evaluated by echocardiography had an Ao PFV>2m/s suggestive of AS. Systolic basilar ejection murmurs were diagnosed in 73%. Murmur intensity showed a statistically significant correlation with Ao PFV (p<0.05). ECG abnormalities were only detected in dogs with severe AS. CONCLUSION The study reports on systolic murmurs and Doppler-echocardiographic findings consistent with AS, as well as ECG and blood pressure measurements in a sample of pure-breed Boxers.

Acute neurological signs as the predominant clinical manifestation in four dogs with Angiostrongylus vasorum infections in Denmark

Four dogs with acute neurological signs caused by haemorrhages in the central nervous system were diagnosed with Angiostrongylus vasorum infection as the underlying aetiology. Two dogs presented with brain lesions, one dog with spinal cord lesions and one with lesions in both the brain and spinal cord. Only one dog presented with concurrent signs of classical pulmonary angiostrongylosis (respiratory distress, cough), and only two dogs displayed overt clinical signs of haemorrhages. Results of coagulation assays were inconsistent. Neurological signs reflected the site of pathology and included seizures, various cranial nerve deficits, vestibular signs, proprioceptive deficits, ataxia and paraplegia. One dog died and three were euthanised due to lack of improvement despite medical treatment. This emphasises canine angiostrongylosis as a potential cause of fatal lesions of the central nervous system and the importance of including A. vasorum as a differential diagnosis in young dogs with acute neurological signs in Denmark.

Hypertrophic cardiomyopathy in young Maine Coon cats caused by the p.A31P cMyBP-C mutation - the clinical significance of having the mutation

BackgroundIn Maine Coon (MC) cats the c.91G > C mutation in the gene MYBPC3, coding for cardiac myosin binding protein C (cMyBP-C), is associated with feline hypertrophic cardiomyopathy (fHCM). The mutation causes a substitution of an alanine for a proline at residue 31 (p.A31P) of cMyBP-C. The pattern of inheritance has been considered autosomal dominant based on a single pedigree. However, larger studies are needed to establish the significance of cats being heterozygous or homozygous for the mutation with respect to echocardiographic indices and the probability of developing fHCM. The objective of the present study was to establish the clinical significance of being homozygous or heterozygous for the p.A31P cMyBP-C mutation in young to middle-aged cats.MethodsThe cohort consisted of 332 MC cats, 282 cats < 4 years (85%). All cats were examined by 2-D and M-mode echocardiography. DNA was extracted from blood samples or buccal swabs and screened for the p.A31P cMyBP-C mutation in exon 3 of the gene, using polymerase chain reaction followed by DNA sequencing.ResultsThe fHCM prevalence was 6.3% in the cohort. Eighteen cats were homozygous and 89 cats were heterozygous for the mutation. The odds ratio for having fHCM for homozygous cats was 21.6 (95% confidence interval 7.01-66.2) - when the group of equivocal cats was categorized as non-affected. Overall, 50% of the cats that were homozygous for the mutation had fHCM. p.A31P heterozygosity was not associated with a significant odds ratio for fHCM. In cats in the 4 to 6 years of age range a similar, non significant, odds ratio was seen in heterozygous cats. Only two cats over four years were homozygous and both were diagnosed with fHCM.ConclusionAs there is no significant odds ratio associated with being heterozygous for the pA31P cMyBP-C mutation at this age, the mutation must have a very low penetrance in this group. From our data it would appear that most MC cats that develop fHCM due to the p.A31P mutation prior to the age of approximately 6 years do so because they are homozygous for this mutation.

Aortic stenosis in the Dogue de Bordeaux.

OBJECTIVES To evaluate the occurrence of aortic stenosis and establish echocardiographic reference values in the Dogue de Bordeaux in Denmark. METHODS Fifty-three dogs were auscultated for evidence of a cardiac murmur and a full echocardiographic examination was performed. The criterion for the diagnosis of aortic stenosis was a peak aortic velocity greater than 2.5 m/s from a subcostal transducer location. RESULTS A left-basilar ejection murmur was detected in 38 (72 per cent) of the dogs. An aortic ejection velocity greater than 2.5 m/s was identified in 9 (17 per cent) of the dogs from a subcostal view. The aortic annulus in Dogue de Bordeaux was smaller than that considered normal in other breeds with comparable body size. Furthermore, a decreased aortoseptal angle was noticed in dogs with aortic stenosis. CLINICAL SIGNIFICANCE The Dogue de Bordeaux may be highly predisposed to aortic stenosis. The small aortic annulus noted in healthy and affected Dogue de Bordeaux and a decreased aortoseptal angle noted in affected dogs in this study might reflect key aetiological features in the development of aortic stenosis.