Canine myxomatous mitral valve disease (MMVD) is similar to Barlow’s form of MMVD in humans. These valvulopathies are complex, with varying speeds of progression. We hypothesized that the relative abundances of serum proteins would help identify the consecutive MMVD stages and discover new disease pathways on a systemic level. To identify distinction-contributing protein panels for disease onset and progression, we compared the proteomic profiles of serum from healthy dogs and dogs with different stages of naturally occurring MMVD. Dogs were divided into experimental groups on the basis of the left-atrium-to-aorta ratio and normalized left ventricular internal dimension in diastole values. Serum was collected from healthy (N = 12) dogs, dogs diagnosed with MMVD in stages B1 (N = 13) and B2 (N = 12) (asymptomatic), and dogs diagnosed with MMVD in chronic stage C (N = 13) (symptomatic). Serum biochemistry and selected ELISAs (galectin-3, suppression of tumorigenicity, and asymmetric dimethylarginine) were performed. Liquid chromatography–mass spectrometry (LC–MS), tandem mass tag (TMT) quantitative proteomics, and statistical and bioinformatics analysis were employed. Most of the 21 serum proteins with significantly different abundances between experimental groups (p < 0.05, FDR ˂ 0.05) were classified as matrix metalloproteinases, protease inhibitors, scaffold/adaptor proteins, complement components, anticoagulants, cytokine, and chaperone. LC–MS TMT proteomics results obtained for haptoglobin, clusterin, and peptidase D were further validated analytically. Canine MMVD stages, including, for the first time, asymptomatic B1 and B2 stages, were successfully distinguished in dogs with the disease and healthy dogs on the basis of the relative abundances of a panel of specific serum proteins. Most proteins with significantly different abundances were involved in immune and inflammatory pathways. Their role in structural remodeling and progression of canine MMVD must be further investigated. Further research is needed to confirm the resemblance/difference with human MMVD. Proteomics data are available via ProteomeXchange with the unique dataset identifier PXD038475.

Giardia duodenalis infections are common in dogs and are mainly caused by assemblages C and D. The aim of this study was to investigate the correlation between the presence of Giardia duodenalis and different Giardia assemblages detected in symptomatic and asymptomatic dogs and the occurrence of certain clinical signs. All the dogs included (n = 82) were clinically examined, and fecal samples were examined for other parasites and Clostridium spp. Also, G. duodenalis assemblages were detected and the occurrence of certain clinical signs was assessed. A total of 42/82 (51.2%) dogs were symptomatic and had one or more gastrointestinal signs, and 40/82 (48.8%) dogs were asymptomatic. G. duodenalis was found in 25/82 (30.5%) dogs: assemblage C in 10/25 (40%) and assemblage D in 15/25 (60%). Only Cryptosporidium spp. showed a higher coinfection rate with G. duodenalis but that did not have an influence on clinical sign appearance. There was no correlation between the presence of different assemblages of G. duodenalis and the sex of the host or the duration and appearance of certain clinical signs, except the presence of mucus in feces, which was more frequent in dogs invaded with G. duodenalis assemblage C. Further research of other assemblages is needed.

The aim of this retrospective study was to determine the prevalence of arrhythmias in dogs admitted to the Clinic for Internal Diseases, Faculty of Veterinary Medicine, University of Zagreb, Croatia. Medical records of 307 dogs that underwent electrocardiographic examination between October 2018 and October 2020 were analysed. The study population (65 breeds, median age 9 years, median body weight 15 kg) showed arrhythmias in 36.2% of cases. The most common arrhythmia was atrial fibrillation (18% of the total population; 26.7% of dogs with heart disease), followed by premature ventricular and atrial contractions. Arrhythmias were also detected in 18.6% of dogs without primary cardiac disease, most often associated with systemic disorders such as tumours, epilepsy, hypoadrenocorticism and arterial hypertension. The results confirm that arrhythmias are frequent in dogs, occurring both in the presence of heart disease and as a consequence of non-cardiac conditions, emphasising the importance of routine electrocardiographic screening in veterinary clinical practice.

Background: Cardiac auscultation remains fundamental to clinical practice; however, large prospective datasets assessing murmur localization and stage-dependent intensity across canine cardiac diseases are scarce. Objectives: To characterize point of maximal intensity (PMI) patterns across cardiac abnormalities in dogs and to assess associations between murmur grade and disease stage in dogs with myxomatous mitral valve disease (MMVD) and dilated cardiomyopathy (DCM).Animals: 6,996 client-owned dogs examined by 50 cardiology-trained veterinarians across internationally distributed centers.Methods: Dogs underwent standardized cardiac auscultation at four predefined thoracic locations and an echocardiographic examination during the same visit. PMI patterns were characterized across cardiac abnormalities, and associations between murmur grade and MMVD and DCM disease stages were evaluated. Results: Dogs with MMVD and DCM predominantly showed a left apical PMI, whereas congenital outflow tract diseases and patent ductus arteriosus were predominantly associated with a left basilar PMI. Tricuspid regurgitation and ventricular septal defect were more commonly associated with right apical and right basilar PMIs, respectively. In dogs with MMVD, murmur intensity increased with advancing stage (p < 0.001). Dogs with a murmur greater than soft had substantially higher odds of being in stage B2 or C/D than B1 (OR 35.9, 95% CI 27.6–46.6). In dogs with DCM, 25.8% had no audible murmur, and murmur intensity did not consistently increase with disease stage (p = 0.03). Conclusions and Clinical Importance: Auscultation reveals disease-associated murmur patterns and provides staging information in MMVD but limited severity assessment in DCM. Echocardiography remains essential for definitive diagnosis and staging.