Parvovirus Infection Is Associated With Myocarditis and Myocardial Fibrosis in Young Dogs

A multimodal approach to diagnosis of neuromuscular neosporosis in dogs

BACKGROUND

Early diagnosis of neosporosis in dogs is challenging.

OBJECTIVES

To evaluate the feasibility of a compound multimodal testing approach for diagnosing in dogs neuromuscular and combined forms of neosporosis.

ANIMALS

A total of 16 dogs diagnosed with solely neuromuscular neosporosis or with a combination of neuromuscular and central nervous system neosporosis.

METHODS

Retrospective review of clinical signs, laboratory findings, treatment, and outcome with focus on the diagnostic utility of different tests. Development of a chromogenic in situ hybridization (ISH) assay for the identification of Neospora caninum in paraffin-embedded muscle samples.

RESULTS

13/16 dogs had only neuromuscular signs of neosporosis, 3/16 had disease signs with concomitant central nervous system (CNS) involvement. Serology was performed in 15/16, with 10/15 showing titers >1 : 160 at admission. PCR on muscle samples detected N. caninum DNA in 11/16. Immunohistochemistry (IHC) detected N. caninum in 9/16 and ISH in 9/16. Histopathology revealed inflammatory myopathy in 10/16, necrotizing myopathy in 5/16, borderline changes in 1/16 and tachyzoites in 9/16. In 4 cases, N. caninum infection was confirmed with all 5 diagnostic methods, 3 cases with 4, 2 with 3, 6 with 2, and 1 animal with 1.

CONCLUSIONS AND CLINICAL IMPORTANCE

Diagnosis of N. caninum infection should rely on a multimodal diagnostic approach and negativity of 1 single test should not allow for exclusion. Serology in combination with direct parasite identification via histopathology, DNA via PCR, or both modalities, appears a reliable diagnostic approach.

A novel lateral flow immunochromatographic assay using a recombinant VP2 antigen for total antibody detection of canine parvovirus-2

Canine parvovirus-2 (CPV-2) is a viral disease of dogs causing acute hemorrhagic gastroenteritis and myocarditis with high morbidity and mortality rates. The infection is still widespread all over the world. Vaccines developed against infection have great importance in preventing infection. However, it is difficult to recommend a practical vaccination program without knowing the antibody level of a puppy. Despite widespread vaccination, difficulties in detecting the maternal antibodies in puppies remain the main cause of vaccination failure. The hemagglutination inhibition (HAI) test is the gold standard to determine the immune status of dogs for canine parvovirus 2, but the HAI test has several disadvantages such as the need for fresh porcine blood, well-equipped laboratory, and long incubation periods. In this study, for the first time we developed a colloidal gold-based competitive lateral flow assay (cLFA) system for the rapid detection of total antibodies in canine serum using CPV-2b-VP2 derived from field isolates. The recombinantly expressed capsid protein of CPV-2 in the prokaryotic expression system was used as a labeled molecule in cLFA. We carried out studies on our cLFA system using the standard antibody solution and the clinical samples from vaccinated puppy serum. We compared the results of the LFAs with the HAI test. Competitive lateral flow assay results showed good correlation with the gold standard method, the HAI test. In the developed platform, the limit of detection of the standard antibody was determined to be 375 ng mL-1, while the cut-off level of antibodies was observed to be 1 : 40 HAI titer in clinical samples. Our reported system will be a strong alternative for CPV-2 antibody-based detection applications.

Carnivore chaphamaparvovirus-1 (CaChPV-1) infection in diarrheic dogs reveals viral endotheliotropism in intestine and lung

BACKGROUND

Carnivore chaphamaparvovirus-1 (CaChPV-1) is a parvovirus identified in dogs and association of infection with diarrhea is controversial. Information on whether tissue tropism persists is lacking.

OBJECTIVES

To determine the disease association of CaChPV-1 in dogs with diarrhea and to investigate viral tropism and genetic diversity.

ANIMALS AND METHODS

CaChPV-1 infection was investigated in five recently deceased puppies and designed a retrospective study to determine whether the presence of CaChPV-1 is associated with diarrhea. The retrospective study was conducted in 137 intestinal tissue samples and 168 fecal samples obtained from 305 dogs. CaChPV-1 tissue localization was determined using in situ hybridization, and CaChPV-1 complete genomes obtained from dead puppies and retrospective study were sequenced and analyzed.

RESULTS

CaChPV-1 was detected in 6.56% (20/305) of tested dogs, including 14 diarrheic- and 6 non-diarrheic dogs, and was significant in puppies with diarrhea (p = 0.048). Among the CaChPV-1-positive diarrheic dogs, one sample was obtained from intestinal tissue and 13 samples were fecal samples. However, six CaChPV-1 positive non-diarrheic dogs were based on fecal samples but not on intestinal tissue. Within the age range, the presence of CaChPV-1 was significant in puppies (p < 0.00001) and was mainly localized in the stromal and endothelial cells of intestinal villi and pulmonary alveoli. Phylogenetic analysis indicated genetic diversity of CaChPV-1 Thai strains that were mostly clustered within the sequences found in China.

CONCLUSIONS

Although definitive pathogenesis of CaChPV-1 remains undetermined, this study provides evidence supporting that CaChPV-1 localizes in canine cells and could play a potential role as an enteric pathogen.

Naturally occurring canine laminopathy leading to a dilated and fibrosing cardiomyopathy in the Nova Scotia Duck Tolling Retriever

Dilated cardiomyopathy (DCM) is characterized by decreased systolic function and dilation of one or both ventricles, often leading to heart failure or sudden death. Two 10-month-old sibling Nova Scotia Duck Tolling Retrievers (NSDTR) died acutely with evidence of dilated cardiomyopathy with myocardial fibrosis. Association analysis using two cases and 35 controls identified three candidate regions homozygous in the two cases. Whole genome sequencing identified a frameshift deletion in the LMNA gene (NC_049228.1:g.41688530del, NP_001274080:p.(Asp576ThrfsTer124)). Three retrospectively identified NSDTRs with sudden death before 2 years of age and severe myocardial fibrosis were also homozygous for the deletion. One 5 year old with sudden death and myocardial fibrosis was heterozygous for the deletion. This variant was not identified in 722 dogs of other breeds, nor was it identified to be homozygous in 784 NSDTR. LMNA codes for lamin A/C proteins, which are type V intermediate filaments that provide structural support to the nuclear membrane. In humans, LMNA variants can cause DCM with sudden death as well as diseases of striated muscles, lipodystrophy, neuropathies, and accelerated aging disorders. This frameshift deletion is predicted to affect processing of prelamin A into lamin A. Pedigree analysis in the NSDTR and functional evaluation of heterozygotes is consistent with a predominantly recessive mode of inheritance and possibly low penetrance in heterozygotes in contrast to people, where most pathogenic LMNA variants are dominantly inherited.

Case report: Long-term survival in puppies assessed with echocardiography, electrocardiography and cardiac troponin I after acute death in littermates due to parvoviral myocarditis

Positive clinical outcomes of a group of surviving puppies from a litter affected by parvoviral myocarditis are detailed in this case report. Past reports focus on the negative outcomes of littermates of puppies who have died of parvoviral myocarditis. In this case, two puppies in a shelter setting, from a litter exposed to parvovirus, died suddenly with parvoviral myocarditis diagnosed at necropsy. The other seven puppies were screened for cardiac health with echocardiogram, electrocardiogram, and cardiac troponin I prior to adoption. All seven puppies had normal echocardiograms, electrocardiograms, and normal initial and recheck cardiac troponin I results. At recheck 2 years after the initial round of testing, two of the puppies were screened and continue to have normal cardiac diagnostics. All seven dogs are alive and thriving at 5 years old in homes with adopters who were given a complete medical history on the dogs prior to adoption. In summary, the outcomes for puppies in litters affected by parvoviral myocarditis are variable but they do not have to be grave. The use of cardiac diagnostics including echocardiogram, electrocardiogram and cardiac troponin I may serve as a prognostic basis for assessing the potential outcomes for the surviving puppies in affected litters.

DEGENERATIVE CARDIAC DISEASE IN TWO SPECIES OF TORTOISE (CHELONOIDIS NIGRA COMPLEX, CENTROCHELYS SULCATA)

Cardiac lesions in tortoises are incompletely described in the literature. This retrospective case series includes 11 cases of degenerative cardiac disease in young tortoises from two species in human care: Galápagos tortoise complex (Chelonoidis nigra complex) (n = 9) and sulcata tortoises (Centrochelys sulcata) (n = 2). Eight tortoises were male, two were female, and sex was undetermined for one individual. The age range at the time of death was 10-32 yr with a mean of 19 yr. The most common clinical signs noted prior to death were peripheral edema, lethargy, and inappetence. Common necropsy findings included generalized edema and pericardial effusion. All cases had ventricular myocardial fibrosis and several cases had epicardial adhesions. Additional common findings included hepatic lesions (hepatic lipidosis, hepatic fibrosis, and hepatitis) and pulmonary lesions (pulmonary edema, pulmonary fibrosis, and pneumocytic hypertrophy). A definitive cause for degenerative cardiac disease was not identified in this case series, but the young age distribution of the tortoises suggests that inappropriate environmental parameters, husbandry, and diet should be investigated as possible underlying contributing factors.

Coagulation Abnormalities in Dogs with Parvoviral Enteritis

Hemostatic alterations have been documented in dogs with canine parvoviral enteritis. This study's aims were to measure the standard coagulation parameters, and to assess the relationship between them and the clinical variables in dogs with canine parvoviral enteritis. Nine client-owned dogs with a canine parvoviral infection were included in a prospective, observational clinical study. Clinical score and coagulation status were assessed at admission. All nine dogs showed alterations of three or more standard coagulation variables. A correlation analysis evidenced a significantly high positive correlation between the activated partial thromboplastin time and clinical score. The present study concurs that dogs with canine parvoviral enteritis have coagulation disorders that are detectable by measuring the standard coagulation parameters.

Molecular characterization of Canine parvovirus type 2 from diarrheic dogs in Serbia from 2008 to 2020

Canine parvovirus 2 (CPV-2) is the causal agent of canine parvovirosis an infectious disease with the high fatality rate among dogs. However, in Serbia, it has never been investigated thoroughly. This study was conducted on samples collected from dogs with diarrhea in anamnesis, submitted for various reasons to the Institute of Veterinary Medicine of Serbia, and stored in the sample bank. In total, 50 rectal swab samples were collected from the period 2008 to 2020, and consequently tested. Out of 50 rectal swab samples, the CPV-2 genome was detected in 14 (28%). This retrospective study showed the presence of three different subtypes of CPV-2 in diarrheic dogs during the last 12 years in Serbia. CPV-2a was the most prevalent subtype (60%) followed by CPV-2b (30%), and CPV-2c (10%). Interestingly, CPV-2a had been the predominantly detected subtype up until 2018. Nevertheless in 2019, there was the first detected occurrence of the CPV-2b, followed by the first detection of the CPV-2c in 2020. This study reports the evidence and distribution of CPV-2 from 2008 to 2020, providing new information about the presence of virus strains in Serbia.

Comparison of echocardiographic measurements and cardiac biomarkers in healthy dogs eating nontraditional or traditional diets

BACKGROUND

There has been a recent association between nontraditional diets and development of diet-associated dilated cardiomyopathy (DCM) in dogs.

HYPOTHESIS/OBJECTIVES

To compare echocardiographic measurements and cardiac biomarkers between healthy dogs eating nontraditional vs traditional diets. We hypothesized that dogs eating nontraditional diets would have lower measures of systolic myocardial performance compared to dogs eating traditional diets.

ANIMALS

Forty-six healthy dogs: 23 eating nontraditional diets and 23 eating traditional diets.

METHODS

Prospective, cross-sectional study. Dogs were divided into groups based on diet ingredients. Dogs underwent 2-dimensional (2D), 3-dimensional (3D), and Doppler echocardiographic examinations and analysis of plasma N-terminal prohormone of B-type natriuretic peptide, serum cardiac troponin I, and whole blood and plasma taurine concentrations.

RESULTS

Mean 2D ejection fraction (EF) was lower for dogs eating nontraditional diets (48.65 ± 7.42%) vs dogs eating traditional diets (56.65 ± 4.63%; P < .001; mean difference 8.0% [4.0%-12.0%] 95% confidence interval [CI]). Mean 3D EF was lower for dogs eating nontraditional diets (45.38 ± 7.35%) vs dogs eating traditional diets (57.58 ± 4.84%; P < .001; 12.0% [8.0%-16.0%] 95% CI). Mean 2D left ventricular end-systolic volumes, indexed to body weight, were significantly higher in dogs eating nontraditional diets (1.46 ± 0.08 mL/kg) vs dogs eating traditional diets (1.06 ± 0.08 mL/kg; P = .002; 0.4 mL/kg [0.18-0.62 mL/kg] 95% CI).

CONCLUSIONS AND CLINICAL IMPORTANCE

Healthy dogs eating nontraditional diets had lower indices of systolic function and larger left ventricular volumes compared to dogs eating traditional diets. Screening of apparently healthy dogs eating nontraditional diets might allow for early detection of diet-associated DCM.

Identification of novel recombinants and proposed standard reference genomes for phylogenetic classification of canine parvovirus-2 (CPV-2): Comprehensive analysis revealing global evolutionary trait

Sustained spread and continuous evolution of CPV-2 generate new genetic information; nevertheless, there is no adopted phylogenetic tool, and parvo virologists still refer to the three antigenic variants. Herein, this report attempted to review the evolutionary trait of CPV-2 and proposed standard reference genomes using the Maximum Likelihood-based phylogenetic analysis and Parsimony-Informative Sites. The analysis revealed three main evolutionary pathways where CPV-2 strains cluster into distinct clades depicted as GI, GII, or GIII, respectively. Furthermore, novel CPV-2 natural recombinants were detected, occurring only between the newly identified strains (2017–2020). Those findings provide unique insights into the evolutionary relatedness of CPV-2, clarify discrepancies between different geographic areas and will contribute to achieving a more reliable CPV-2 genetic and evolutionary genotyping classification.

Experimental study of tropism of cultivated canine parvovirus in the immunogenesis organs of puppies

The immune system unites the organs and the tissues that protect the organism against genetically alien cells or substances entering the organism from the environment. Canine parvovirus is an etiologic agent of hemorrhagic gastroenteritis and causes a significant problem for veterinary medicine due to high level of morbidity and mortality, mostly among dogs, because of fast progression without immune-complement response. In this study, based on the results of our clinical, virological, histological, histochemical and morphological assays, we determined the pathogenetic role of parvovirus in sick dogs experimentally infected per os, specifically with isolated canine parvovirus (Antaeus) with titer of infectious activity equaling 3.80 ± 0.008 lg TCID50/cm, cultivated on heterological cell cultures. This allowed us to clarify, add to and generalize the data on the pathogenesis of the disease and determine pathohistological and histochemical changes in the immunogenesis, since the studied virus expresses immune-suppressive properties, leading to ruination of the locomotor ability of the organism and fast lethal outcome. The study of pathomorphological changes was carried out using pathoanatomical and histologic methods. Pathoanatomical material from the autopsy of puppies aged 45 days was fixed in 10% aqueous solution of neutral formaline and embedded in paraffin. Having parvoviral infection, dogs experience pathomorphologic changes in immune-complement organs, indicating inhibition of the immunogenesis function during an infectious disease of viral etiology. In the immunogenesis organs of puppies with the experimental reconstruction of parvoviral enteritis, we microscopically determined the following: edema of the cortex and medulla, disorganization of thymic corpuscules, and impairment of processes of differentiation of lymphocytes in the cortex and medulla of the thymic lobules; edema and large areas of accumulation of hemosiderin in the spleen as a result of breakdown of large amount of erythrocytes; acute inflammatory hyperemia of the parenchyma, swelling of sinuses, serous and serous-hemorrhagic lymphadenitis in lymph nodes. The complex of histologic changes in the immune protection organs, which we found in the conditions of experimental reconstruction of parvoviral infection, can be considered a distinct criterion for pathomorphologic differentiation diagnostics of parvoviral enteritis in dogs.

Distribution and diversity of dog parvoviruses in wild, free-roaming and domestic canids of Newfoundland and Labrador, Canada

Some parvoviruses of carnivorans can infect multiple host species. Since many canine parvoviruses were only discovered recently, their host-range is still unexplored. We examined the host distribution and diversity of five dog parvoviruses in four canine populations from Newfoundland and Labrador, Canada, and investigated the potential for these viruses to cross the species barriers. Canine bocavirus 2 (CBoV-2) and the minute virus of canines were detected in stool from free-roaming dogs from Labrador (5/48 [10.4%] and 3/48 [6.3%], respectively) and two different CBoV-2 variants were identified. Canine bufavirus was identified in stool from free-roaming dogs (1/48, 2.1%) and foxes (3/80, 3.8%) from Labrador, but two different variants were observed in the two host species. The variant found in foxes was highly divergent from previously identified strains. Two cachavirus 1 variants, genetically similar to those circulating in other Canadian wildlife, were found in spleens from Newfoundland coyotes (3/87, 3.5%). Canine parvovirus type 2 (CPV-2) was found in stool from free-roaming dogs from Labrador (2/48, 4.2%) and in spleens from Newfoundland coyotes (3/87, 3.5%). Comparing CPV-2 sequences from these hosts to those retrieved from local symptomatic domestic dogs revealed the presence of a highly heterogeneous viral population as detected strains belonged to five different clades. The close relationship between CPV-2a strains from a dog and a coyote suggests the occurrence of viral transfer between wild and domestic canids. The identification of highly related strains with a similar molecular signature characteristic of older CPV-2 strains in free-roaming and domestic dogs suggests a probable common ancestry and that older CPV-2 strains, which have not been identified in dogs since the 1990s, persist in this part of Canada. Follow-up studies should evaluate samples from a larger number of animals and host species to extensively investigate the possible occurrence of cross-species transmission for recently discovered parvoviruses.

Myocardial Iba1, MHC class II, and CD3 are diffusely increased in canine myocarditis: A step toward antemortem myocarditis diagnostics

Canine myocarditis is a rare but serious health concern, potentially causing heart failure and death. Antemortem diagnosis is hampered by the numerous causes, nonspecific course, and dearth of diagnostic criteria. Currently, definitive diagnosis can only be made after death. The current human diagnostic gold standard is endomyocardial biopsy pairing cardiac histopathology with immunohistology to enhance detection of often-multifocal disease. We evaluated immune response markers in the canine heart to establish similar immunohistologic criteria. We hypothesized that myocardial major histocompatibility complex class II (MHCII), cluster of differentiation 3 (CD3), and ionized calcium binding adapter molecule 1 (Iba1), markers increased in human myocarditis, would be increased in canine myocarditis cases. Archived paraffin-embedded myocardial tissue from 22 histopathologically confirmed cases of adult and juvenile myocarditis and 23 controls was analyzed by immunohistochemistry for MHCII, CD3, and Iba1, and the fraction of myocardium with labeling was determined. All 3 markers were significantly increased compared with controls across the entire section: Iba1, 10.1× (P < .0001, Mann-Whitney U test); MHCII, 3.04× (P = .0019); and CD3, 4.4× (P = .0104). To mimic off-target biopsy, samples from 2 mm² outside of inflammatory foci were analyzed, and these showed significant increases in Iba1 by 3.2× (P = .0036, Mann-Whitney U test) and CD3 by 1.2× (P = .0026). These data show diffusely increased immune response markers with canine myocarditis, with detection potentially independent of tissue sampling. Thus, endomyocardial biopsy and immunohistochemical detection of MHCII, CD3, and Iba1 may permit sensitive antemortem diagnosis of canine myocarditis.

Association of diet with clinical outcomes in dogs with dilated cardiomyopathy and congestive heart failure

INTRODUCTION

Dilated cardiomyopathy (DCM) in dogs has been associated with feeding of grain-free (GF), legume-rich diets. Some dogs with presumed diet-associated DCM have shown improved myocardial function and clinical outcomes following a change in diet and standard medical therapy.

HYPOTHESIS

Prior GF (pGF) diet influences reverse cardiac remodeling and clinical outcomes in dogs with DCM and congestive heart failure (CHF).

ANIMALS AND METHODS

A retrospective study was performed with 67 dogs with DCM and CHF for which diet history was known. Dogs were grouped by diet into pGF and grain-inclusive (GI) groups. Dogs in the pGF group were included if diet change was a component of therapy. Survival was analyzed using Kaplan-Meier curves and the Cox proportional-hazards model.

RESULTS

The median survival time was 344 days for pGF dogs vs. 253 days for GI dogs (P = 0.074). Statistically significant differences in median survival were identified when the analysis was limited to dogs surviving longer than one week (P = 0.033). Prior GF dogs had a significantly worse outcome the longer a GF diet was fed prior to diagnosis (P = 0.004) or if they were diagnosed at a younger age (P = 0.017). Prior GF dogs showed significantly greater improvement in normalized left ventricular internal diastolic diameter (P = 0.038) and E-point septal separation (P = 0.031) measurements and significant decreases in their furosemide (P = 0.009) and pimobendan (P < 0.005) dosages over time compared to GI dogs.

CONCLUSIONS

Prior GF dogs that survived at least one week after diagnosis of DCM, treatment of CHF, and diet change had better clinical outcomes and showed reverse ventricular remodeling compared to GI dogs.

Canine parvovirology - A brief updated review on structural biology, occurrence, pathogenesis, clinical diagnosis, treatment and prevention

Canine parvovirus (CPV) is a major cause of hemorrhagic diarrhea and mortality in puppies worldwide. There are 2 types of Parvovirus which affects canines: Canine parvovirus 2 (CPV-2) and Canine parvovirus 1 (CPV-1) or the Minute Virus of Canine (MVC). CPV-2 originated from Feline panleukopenia virus and has undergone genetic variation to give rise to its three variants (CPV-2a, CPV-2b and CPV-2c). Amino acid substitutions in VP2 capsid protein have led virus to adapt new host range. The original CPV-2 was known to be dominant in Japan, Belgium, Australia as well as USA and later circulated throughout the world. Clinically, CPV-2 infection is characterized by anorexia, lethargy, depression, vomiting, leukopenia and severe hemorrhagic diarrhea. Several diagnostic tests have been developed to detect parvoviral infections which are categorized into immunological tests (latex agglutination test, SIT-SAT and ELISA etc.) and molecular based tests (PCR, mPCR and RT-PCR etc.). To control and manage the disease several treatments like fluid therapies, antibiotics, and adjunctive treatments are available and some are in various stages of development. Apart from this, many vaccines are also commercially available and some are in developmental stages. The present review contains detailed information regarding structural biology, occurrence, pathogenesis, clinical diagnosis, treatments and prevention in order to understand the need and the growing importance of CPV-2.

Small but mighty: old and new parvoviruses of veterinary significance

In line with the Latin expression "sed parva forti" meaning "small but mighty," the family Parvoviridae contains many of the smallest known viruses, some of which result in fatal or debilitating infections. In recent years, advances in metagenomic viral discovery techniques have dramatically increased the identification of novel parvoviruses in both diseased and healthy individuals. While some of these discoveries have solved etiologic mysteries of well-described diseases in animals, many of the newly discovered parvoviruses appear to cause mild or no disease, or disease associations remain to be established. With the increased use of animal parvoviruses as vectors for gene therapy and oncolytic treatments in humans, it becomes all the more important to understand the diversity, pathogenic potential, and evolution of this diverse family of viruses. In this review, we discuss parvoviruses infecting vertebrate animals, with a special focus on pathogens of veterinary significance and viruses discovered within the last four years.

Screening for dilated cardiomyopathy in dogs

BACKGROUND

Dilated cardiomyopathy (DCM) is the most common cardiac disease in large breed dogs. The disease can start with arrhythmias or with systolic dysfunction of the myocardium.

OBJECTIVE

To describe screening methods for DCM in various breeds and provide a new, modified staging system.

RECOMMENDATIONS

Screening for occult DCM should start at three years of age and use Holter monitoring in Boxers and Dobermans and might be useful also in other breeds. Single ventricular premature complexes (VPCs) can be detected in many healthy dogs, but healthy animals typically have <50 VPCs in 24 h and demonstrate minimal complexity most often occurring only as single ectopic beats. In general, >100 VPCs in 24 h was recommended as the cut-off value for establishing a diagnosis of DCM. However, there are breed-specific recommendations related to Holter recording diagnosis of DCM in Dobermans and Boxers. Yearly screening over the life of a dog is recommended, as a one-time screening is not sufficient to rule out the future development of DCM. Several echocardiographic methods such as M-mode derived measurements, the measurement of the left ventricular (LV) volume by Simpson's method of discs (SMOD), and E-point to septal separation (EPSS) are recommended for screening purposes. The value of additional tests such as cardiac biomarkers (troponin I and N-terminal pro-B-type natriuretic peptide) as well as a 5-min resting electrocardiogram (ECG) or newer echocardiographic methods such as strain measurements is discussed.

CONCLUSION

This review suggests some guidelines for screening for DCM in various breeds.

Porcine Parvovirus 2 Is Predominantly Associated With Macrophages in Porcine Respiratory Disease Complex

Porcine respiratory disease complex (PRDC) is a significant source of morbidity and mortality, manifested by pneumonia of multiple etiologies, where a variety of pathogens and environment and management practices play a role in the disease. Porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and porcine circovirus 2 (PCV2) are well-established pathogens in PRDC. Porcine parvovirus 2 (PPV2) has been identified in both healthy and clinically diseased pigs at a high prevalence worldwide. Despite widespread circulation, the significance of PPV2 infection in PRDC and its association with other co-infections are unclear. Here, PPV2 was detected in the lung tissue in 39 of 100 (39%) PRDC-affected pigs by quantitative polymerase chain reaction (qPCR). Using in situ hybridization (ISH) in conjunction with tissue microarrays (TMA), PPV2 infection was localized in alveolar macrophages and other cells in the lungs with interstitial pneumonia in 28 of 99 (28.2%) samples. Viral load tended to correlate with the number of macrophages in the lungs. Assessment of the frequency, viral titers, and tissue distributions showed no association between infection of PPV2 and other major viral respiratory pathogens. In one-third of the PPV2-positive samples by qPCR, no other known viruses were identified by metagenomic sequencing. The genome sequences of PPV2 were 99.7% identical to the reference genomes. Although intensive intranuclear and intracytoplasmic signals of PPV2 were mainly detected in alveolar macrophages by ISH, no obvious virus replication was noted in in vitro cell culture. Together, these results suggest that PPV2 is associated, but may not be the sole causative agent, with PRDC, warranting the control and prevention of this underdiagnosed virus.

Parvoviral enteritis and salmonellosis in raccoons with sudden death

Eight of 9 juvenile raccoons at a rehabilitation center died without obvious prior clinical signs. Gross changes were unremarkable except for mildly distended intestines. Microscopically, crypt loss, distension, necrosis, and regeneration with intranuclear viral inclusions were observed in the small intestine, with marked lymphoid depletion and necrosis in Peyer patches and mesenteric lymph nodes. Immunohistochemistry with a canine parvovirus antibody showed intensive signals of parvoviral antigens in the crypts and lymphoid germinal centers. Metagenomic sequencing allowed assembly of a complete parvoviral genome with >99% identity to canine parvovirus 2a, as well as Salmonella enterica subsp. enterica. Also, S. enterica subsp. enterica serovar Thompson with multiple antimicrobial resistance was isolated from the intestinal contents. Concurrent infection with parvovirus and Salmonella should be included as a differential diagnosis in raccoons with sudden death.

Canine Parvovirus Infections in Taiwanese Pangolins (Manis pentadactyla pentadactyla)

Canine parvovirus type 2 (CPV-2) is among the most important and highly contagious pathogens that cause enteric or systemic infections in domestic and nondomestic carnivores. However, the spillover of CPV-2 to noncarnivores is rarely mentioned. Taiwanese pangolins (Manis pentadactyla pentadactyla) are threatened due to habitat fragmentation and prevalent animal trafficking. Interactions between Taiwanese pangolins, humans, and domestic animals have become more frequent in recent years. However, information about the susceptibility of pangolins to common infectious agents of domestic animals has been lacking. From October 2017 to June 2019, 4 pangolins that were rescued and treated in wildlife rescue centers in central and northern Taiwan presented with gastrointestinal signs. Gross and histopathological examination revealed the main pathologic changes to be necrotic enteritis with involvement of the crypts in all intestinal segments in 2 pangolins. By immunohistochemistry for CPV-2, there was positive labeling of cryptal epithelium throughout the intestine, and immunolabeling was also present in epidermal cells adjacent to a surgical amputation site, and in mononuclear cells in lymphoid tissue. The other 2 pangolins had mild enteritis without crypt involvement, and no immunolabeling was detected. The nucleic acid sequences of polymerase chain reaction (PCR) amplicons from these 4 pangolins were identical to a Chinese CPV-2c strain from domestic dogs. Quantitative PCR revealed a higher ratio of CPV-2 nucleic acid to internal control gene in the 2 pangolins with severe intestinal lesions and positive immunoreactivity. Herein, we present evidence of CPV-2 infections in pangolins.

Systolic dysfunction by two-dimensional speckle tracking echocardiography in dogs with parvoviral enteritis

INTRODUCTION/OBJECTIVES

Parvoviral enteritis (PVE) can cause either primary or secondary myocardial injury; the latter is associated with systemic inflammatory response syndrome and sepsis. Strain (St) and strain rate (SR) are relatively new speckle tracking echocardiographic (STE) variables used to assess myocardial function and are less influenced by preload and volume status than are conventional variables. The aim of this study was to evaluate systolic function in dogs with PVE using two-dimensional STE.

ANIMALS

Forty-five client-owned dogs were included.

MATERIALS AND METHODS

Dogs were classified into four groups: healthy (n = 9), PVE-mild (n = 15), PVE-severe (n = 13) and PVE-died (n = 8). Left ventricular global and segmental myocardial St and SR were assessed in radial, circumferential and longitudinal axes in the right parasternal transverse and apical 4-chamber views. In the circumferential and longitudinal axes, the value of each segment was determined separately at the endocardial and epicardial levels.

RESULTS

Compared to healthy animals, all dogs with PVE showed significantly impaired St and SR values, mainly for PVE-severe and PVE-died groups. Moreover, the lowest SR value was observed in the circumferential axis at the mid-septal epicardial segment in the PVE-died group. For this variable, a cut-off value of 0.95 s^-1 demonstrated 100% sensitivity and specificity for distinguishing between PVE-severe and PVE-died groups.

CONCLUSIONS

In the present study, all dogs with PVE developed systolic dysfunction, which was more severe in non-survivors. Assessment of St and SR in dogs with PVE might be clinically useful for evaluating haemodynamic status and developing suitable therapeutic strategies to improve prognosis.

Myocarditis caused by naturally acquired canine distemper virus infection in 4 dogs

Canine distemper virus (CDV) has long been recognized as a cause of myocarditis; however, cases of myocarditis caused by naturally acquired CDV infection have been reported only rarely in dogs. We describe here our retrospective study of naturally acquired systemic CDV infection in 4 dogs, 4-7 wk old, that had myocarditis, with myocardial necrosis and fibrosis. One of the 4 dogs had intracytoplasmic eosinophilic inclusion bodies in cardiomyocytes. Other lesions included bronchointerstitial pneumonia (4 of 4), necrotizing hepatitis (2 of 4), splenic lymphoid necrosis (2 of 4), encephalitis (1 of 3; brain was not submitted in 1 case), and necrotizing gastroenteritis (1 of 4). The presence of CDV in the heart was confirmed by immunohistochemistry in all 4 dogs.

First detection of canine parvovirus 2b DNA in a crab-eating fox pup (Cerdocyon thous, Linnaeus, 1766)

The crab-eating fox (Cerdocyon thous) is a small wild mammal present in all Brazilian biomes and in some countries of South America. This study aimed to verify the involvement of viral infectious agents in the death of a wild crab-eating fox pup (Cerdocyon thous) in Brazil. The Center for Medicine and Research of Wild Animals of the Universidade Estadual Paulista received a free-living crab-eating fox aged approximately 21 days and apparently healthy. After 13 days, the animal presented anorexia, diarrhea, fever, prostration, and neurological signs progressing to death with an inconclusive diagnosis. In a retrospective study, tissue fragments stored at - 80 °C were used to identify nucleic acids from major canine viruses, such as canine parvovirus-2 (CPV-2), canine adenovirus A types 1 and 2, canid alphaherpesvirus 1, and canine distemper virus. The amplified product with the expected length for CPV-2 was obtained from the heart fragment. After performing nucleotide (nt) sequencing of the amplicon, it was possible to demonstrate that the crab-eating fox strain exhibited high (99.8%) nt identity with the CPV-2b prototype (CPV-39 strain). Additionally, deduced amino acid (aa) sequence analysis showed the GAT codon for the aa Asp (D) at position 426 of the CPV-2 viral protein VP2, which characterizes the subtype 2b. To the best of the authors' knowledge, this report describes the first detection of CPV-2b DNA in tissue fragments from a crab-eating fox.

Endocardial fibroelastosis in a dog with congestive heart failure

In a 6-month-old, intact female, Japanese spitz presenting with severe dyspnea, lung ultrasonography revealed confluent B lines associated with severe echocardiographic left sided volume overload and systolic dysfunction. A congenital shunt or valvular dysplasia was not demonstrable. On electrocardiogram, there was a constant sinus rhythm, respectively sinus tachycardia. Cardiac troponin I was normal. Within 2 days of admission, the dog died of heart failure. On macroscopic postmortem examination, the left ventricle and atrium were markedly dilated, and the left ventricular endocardium had a mild diffuse whitish appearance. Histopathology revealed moderate to severe thickening of the left ventricular endocardium, composed mostly of abundant elastic fibers and fewer collagen fibers, diagnostic for endocardial fibroelastosis. In addition, there were mild degenerative changes of the atrioventricular valves. Endocardial fibroelastosis is a rare congenital disease and should be considered in a young dog if more common causes of echocardiographic dilated cardiomyopathy phenotype are ruled out.

Update on Canine Parvoviral Enteritis

Canine parvoviral enteritis is one of the most common causes of morbidity and mortality in dogs worldwide. Tests can detect viral antigen in feces, and characteristic decreases in total leukocyte, neutrophil, and lymphocyte counts can increase the index of suspicion in affected cases and can be used to prognosticate morbidity and mortality. The standard of care for infected animals includes IV crystalloid and sometimes colloid fluids, antiemetics, broad-spectrum antibiotics, and early enteral nutrition. Vaccination induces protective immunity in most dogs. Vaccination, along with limiting exposure in young puppies, is the most effective means of preventing parvoviral enteritis in dogs.

Clinical presentation, cardiovascular findings, etiology, and outcome of myocarditis in dogs: 64 cases with presumptive antemortem diagnosis (26 confirmed postmortem) and 137 cases with postmortem diagnosis only (2004-2017)

INTRODUCTION

This study describes presentation, cardiovascular abnormalities, etiology, and outcome of canine myocarditis in geographic areas not endemic for Trypanosoma or Leishmania.

ANIMALS

Sixty-four (presumed antemortem diagnosis) and 137 (postmortem diagnosis only) client-owned dogs at two tertiary care facilities were included.

MATERIALS AND METHODS

Medical records of dogs with clinical or histopathological diagnosis of myocarditis were reviewed retrospectively.

RESULTS

Common examination findings in dogs with a presumed antemortem diagnosis included fever (21%) and heart murmur (19%). Median cardiac troponin I was 12.2 ng/mL (range: 0.2-808.0 ng/mL), and troponin exceeded 1.0 ng/mL in 26 of 29 (90%) dogs. Ventricular ectopy was the most common arrhythmia (54%), whereas decreased left ventricular systolic function was the most common echocardiographic abnormality (56%). An infectious etiology was diagnosed in 35 of 64 (55%) dogs. Confirmed infectious etiologies included bacterial sepsis (n = 9) or extension of endocarditis (3), toxoplasmosis or neosporosis (3), parvovirus (2), and one case each of bartonellosis, trypanosomiasis, leptospirosis, and dirofilariasis. Median survival time was 4 days (range: 0-828 days) for all dogs vs. 82 days for dogs who survived at least 2 weeks after diagnosis. Presence of pericardial effusion or azotemia was a significant predictor of non-survival. The most common inflammatory infiltrate on histopathology was neutrophilic (47%), and 20 of 137 (14.5%) dogs had concurrent bacterial endocarditis on postmortem.

CONCLUSIONS

Bacterial infection was the most common confirmed etiology of myocarditis in this study. Prognosis for canine myocarditis is guarded and similar to that reported for infective endocarditis. Criteria for the antemortem diagnosis of canine myocarditis are suggested.

Prevalence of selected cardiotropic pathogens in the myocardium of adult dogs with unexplained myocardial and rhythm disorders or with congenital heart disease

OBJECTIVE

To determine the prevalence of nucleic acid from selected cardiotropic pathogens in endomyocardial biopsy samples from dogs with unexplained myocardial and rhythm disorders (UMRD) and compare prevalence with that for a group of control dogs with congenital heart disease (CHD).

ANIMALS

47 client-owned dogs.

PROCEDURES

Right ventricular endomyocardial biopsy was performed in dogs with UMRD (dilated cardiomyopathy [n = 25], atrioventricular block [6], and nonfamilial ventricular [4] and supraventricular arrhythmias [2]) or CHD (10) that required right ventricular catheterization. Biopsy samples were evaluated histologically, and PCR assays were used for detection of nucleic acid from 12 pathogens.

RESULTS

197 biopsy samples were collected from dogs with UMRD (n = 172) or CHD (25). At least 1 pathogen was detected in 21 of 37 (57%; 95% confidence interval [CI], 41% to 71%) dogs with UMRD, and canine coronavirus was detected in 1 of 10 (10%; 95% CI, 2% to 40%) dogs with CHD. Dogs with UMRD were significantly more likely than dogs with CHD to have pathogens detected in biopsy samples (OR, 11.8; 95% CI, 1.3 to 103.0). The most common pathogens in dogs with UMRD were canine distemper virus, canine coronavirus, canine parvovirus 2, and Bartonella spp. No pathogens were detected in available blood samples from dogs with pathogens detected in biopsy samples.

CONCLUSIONS AND CLINICAL RELEVANCE

Detection of nucleic acids from selected cardiotropic pathogens in myocardial tissue from dogs with UMRD suggested a possible association between the 2. Further studies are needed to explore whether this association is causative or clinically important. (J Am Vet Med Assoc 2019;255:1150-1160).

Review of canine dilated cardiomyopathy in the wake of diet-associated concerns

Dilated cardiomyopathy (DCM) has been in the literature and news because of the recent opinion-based journal articles and public releases by regulatory agencies. DCM is commonly associated with a genetic predisposition in certain dog breeds and can also occur secondary to other diseases and nutritional deficiencies. Recent communications in veterinary journals have discussed a potential relationship between grain-free and/or novel protein diets to DCM, citing a subjective increase in DCM in dog breeds that are not known to have a genetic predisposition for the disease. This literature review describes clinical presentations of DCM, common sequelae, treatment and preventative measures, histopathologic features, and a discussion of the varied etiological origins of the disease. In addition, current literature limitations are addressed, in order to ascertain multiple variables leading to the development of DCM. Future studies are needed to evaluate one variable at a time and to minimize confounding variables and speculation. Furthermore, to prevent sampling bias with the current FDA reports, the veterinary community should be asked to provide information for all cases of DCM in dogs. This should include cases during the same time period, regardless of the practitioner's proposed etiology, due to no definitive association between diets with specific characteristics, such as, but not limited to, grain-free diets and those containing legumes, novel protein diets, and those produced by small manufacturers to DCM in dogs. In summary, in order to determine if certain ingredients, categories of diets, or manufacturing processes are related to an increased risk of DCM, further studies investigating these variables are necessary.

A Decade of Treatment of Canine Parvovirus in an Animal Shelter: A Retrospective Study

Here, we present 11.5 years of monthly treatment statistics showing an overall intake of 5127 infected dogs between June 2008 and December 2019, as well as more detailed datasets from more recent, less protracted time periods for the examination of mortality risk, seasonality, and resource requirements in the mass treatment of canine parvovirus (CPV) in a private animal shelter. The total survival rate of animals during the study period was 86.6% (n = 4438/5127 dogs survived) with the probability of survival increasing to 96.7% after five days of treatment (with 80% of fatalities occurring in that period). A distinct parvovirus season peaking in May and June and troughing in August, September, December, and January was observed, which could have contributed as much as 41 animals peak-to-trough in the monthly population (with a potential, smaller season occurring in October). Low-weight and male animals were at higher risk for death, whereas age was not a significant contributing factor. Treatment time averaged 9.03 h of total care during a seven-day median treatment duration. These findings, taken together, demonstrate that canine parvovirus can be successfully treated in a sustainable manner within a shelter setting using a largely volunteer workforce.

Canine parvovirus 2b in fecal samples of asymptomatic free-living South American coatis (Nasua nasua, Linnaeus, 1766)

Canine parvovirus type 2 (CPV-2) is classified into three subtypes (CPV-2a, CPV-2b, and CPV-2c) and is the main cause of enteritis and myocarditis in young domestic and wild animals. This study aimed to evaluate the presence of CPV-2 in the feces of asymptomatic free-living coatis from Garden Forest Reserve, Palmital city, SP, Brazil. Fecal samples from 21 coatis (both sexes, different ages, and different aspects of feces) were collected in August 2014 and March 2015. The nucleic acid extracted was submitted to a polymerase chain reaction (PCR) assay to amplify a fragment of the VP2 gene of CPV-2. Eight (38%) fecal samples were positive in the PCR assay and were confirmed by sequencing. The 7 nucleotide (nt) sequences analyzed showed 100% nt identity with the prototype strain of CPV-2b (CPV-39 strain). The analysis of the deduced amino acid (aa) sequence revealed the presence of the GAT codon (aa D-Asp) at position 426 of the VP2 viral protein (subtype 2b). This study describes for the first time the identification of CPV-2b in asymptomatic free-living coatis (Nasua nasua) and suggests that coatis are susceptible to Carnivore protoparvovirus 1 infection and are important as a reservoir and an asymptomatic carrier to other wild and domestic animal species.

Serological survey of canine parvovirus 2 antibody titres in breeding kennels in northern Italy

BACKGROUND

Current guidelines recommend parvovirus revaccination of adult dogs no more frequently than every 3 years. The aim of this study was to determine the prevalence of dogs showing protective serum antibody titres against canine parvovirus 2 in breeding kennels in Northern Italy and to assess the effect of time from vaccination and the sex of the dog on antibody titres. The study was carried out on 370 animals of different breeds kept in 33 breeding kennels. Antibodies to canine parvovirus 2 in serum samples were measured with an indirect immunoenzymatic assay validated by the manufacturer in relation to the 'gold standard' haemagglutination inhibition test. The number of months that had elapsed since the last vaccination was calculated for each animal and categorized into the following classes: < 12 months; 13-24 months; 25-36 months; 37-48 months; and > 49 months.

RESULTS

The prevalence of 'unprotected' dogs was 4.6%. A satisfactory solid herd immunity was present in the majority of breeding kennels, although some vaccination failures were detected. A significant negative correlation was found between antibody titre and months since last vaccination. Comparable antibody titres were found in the first 3 years after vaccination. Although the antibody titre over time was not affected by the sex of the dog, 'unprotected' females had been vaccinated more recently than males with analogous low titres.

CONCLUSIONS

Parvovirus revaccination of adult dogs every 3 years, as currently recommended, is also the appropriate recommendation for breeding kennels. Serological tests could be a useful tool to assess the effectiveness of vaccination.

The Causes of Canine Myocarditis and Myocardial Fibrosis Are Elusive by Targeted Molecular Testing: Retrospective Analysis and Literature Review

Myocarditis can cause death or permanent heart damage. As epidemiologic and etiopathologic data for canine myocarditis are lacking, we performed a retrospective study using nucleic acid extracted from archived (2007 to 2015) tissues from myocarditis cases and control dogs without myocardial lesions. Heart tissue from pediatric/juvenile and adult dogs was tested with a comprehensive panel of conventional and real-time polymerase chain reaction (PCR) assays targeting recognized agents of canine myocarditis based on a literature review and informed by the comparative epidemiology of human myocarditis. The PCR screen, which included canine parvovirus 2 (CPV-2), canine distemper virus, canine herpesvirus, Borrelia spp, West Nile virus, adenovirus, parainfluenza virus, pneumovirus, respiratory coronavirus, influenza virus, Bartonella spp, Rickettsia spp, Mycoplasma spp, and Neospora caninum, did not detect agents in 35 of 66 cases (53%; 95% confidence interval [CI], 41%-65%) and was frequently negative in adults (21/26); by comparison, agents were not detected in 27 of 57 controls (47%; 95% CI, 35%-60%). Canine distemper virus, herpesvirus, adenovirus, coronavirus, parainfluenza virus, Mycoplasma haemocanis, and N. caninum were occasionally detected in both cases and controls; thus, PCR detection was not considered to indicate causation. We previously reported that CPV-2 continues to be associated with myocarditis in young dogs despite widespread vaccination; in adults, CPV-2 was detected in 2 of 26 cases and 4 of 22 controls. As several agents were similarly detected in cases and controls, it is unclear if these are cardiopathogenic, incidental, or latent. West Nile virus was detected at the analytic limit in 1 adult case. We did not detect Borrelia spp, Bartonella spp, Rickettsia spp, or influenza A virus in the myocarditis cases. These data demonstrate the limitations of current targeted diagnostic tests and the need for additional research to identify unknown agents and develop testing strategies for canine myocarditis.

Canine parvovirus (CPV) phylogeny is associated with disease severity

After its first identification in 1978, canine parvovirus (CPV) has been recognized all around the world as a major threat for canine population health. This ssDNA virus is characterized by a high substitution rate and several genetic and phenotypic variants emerged over time. Overall, the definition of 3 main antigenic variants was established based on specific amino acid markers located in a precise capsid position. However, the detection of several minor variants and incongruence observed between the antigenic classification and phylogeny have posed doubts on the reliability of this scheme. At the same time, CPV heterogeneity has favored the hypothesis of a differential virulence among variants, although no robust and consistent demonstration has been provided yet. The present study rejects the antigenic variant concept and attempts to evaluate the association between CPV strain phylogeny, reconstructed using the whole information contained in the VP2 coding gene, and several clinical and hemato-biochemical parameters, assessed from 34 CPV infected dogs at admission. By using different statistical approaches, the results of the present study show an association between viral phylogeny and host parameters ascribable to immune system, coagulation profile, acute phase response and, more generally, to the overall picture of the animal response. Particularly, a strong and significant phylogenetic signal was proven for neutrophil count and WBC. Therefore, despite the limited sample size, a relation between viral phylogeny and disease severity has been observed for the first time, suggesting that CPV virulence is an inherited trait. The likely existence of clades with different virulence highlights once more the relevance of intensive epidemiological monitoring and research on CPV evolution to better understand the virulence determinants, their epidemiology and develop adequate countermeasures.

Lymphoplasmacytic Meningoencephalitis and Neuronal Necrosis Associated With Parvoviral Infection in Cats

Neurologic manifestations other than cerebellar hypoplasia are rarely associated with feline panleukopenia virus (FPV) infection in cats. Here the authors describe lymphoplasmacytic meningoencephalitis and neuronal necrosis in 2 cats autopsied after exhibiting ataxia and nystagmus. Gross changes consisted of cerebellar herniation through the foramen magnum, with flattening of cerebrocortical gyri and narrowing of sulci. Histologically, lymphoplasmacytic meningoencephalitis, extensive neuronal necrosis, and neuroaxonal degeneration with digestion chambers were present in the telencephalon and brain stem in both cats. Frozen brain tissue of both cats was positive for parvoviral antigen via fluorescent antibody testing, and formalin-fixed, paraffin-embedded tissue sections of brain were immunoreactive for parvovirus antigen and positive for parvoviral DNA on in situ hybridization. Frozen brain tissue from 1 case was positive for parvovirus NS1 and VP2 genes using conventional polymerase chain reaction, and subsequent DNA sequencing and phylogenetic analysis revealed that the viral strain was a FPV. Reverse transcription quantitative polymerase chain reaction on formalin-fixed, paraffin-embedded brain tissue revealed high levels of parvovirus in both cases, supporting an acute and active viral infection. Although rare, FPV infection should be considered in cases of lymphoplasmacytic meningoencephalitis and neuronal necrosis in cats.

Echocardiographic phenotype of canine dilated cardiomyopathy differs based on diet type

INTRODUCTION

Canine dilated cardiomyopathy (DCM) can result from numerous etiologies including genetic mutations, infections, toxins, and nutritional imbalances. This study sought to characterize differences in echocardiographic findings between dogs with DCM fed grain-free (GF) diets and grain-based (GB) diets.

ANIMALS

Forty-eight dogs with DCM and known diet history.

METHODS

This was a retrospective analysis of dogs with DCM from January 1, 2015 to May 1, 2018 with a known diet history. Dogs were grouped by diet (GF and GB), and the GF group was further divided into dogs eating the most common grain-free diet (GF-1) and other grain-free diets (GF-o). Demographics, diet history, echocardiographic parameters, taurine concentrations, and vertebral heart scale were compared between GB, all GF, GF-1, and GF-o groups at diagnosis and recheck.

RESULTS

Dogs eating GF-1 weighed less than GB and GF-o dogs, but age and sex were not different between groups. Left ventricular size in diastole and systole was greater, and sphericity index was less for GF-1 compared with GB dogs. Diastolic left ventricular size was greater for all GF compared with that of GB dogs. Fractional shortening, left atrial size, and vertebral heart scale were not different between groups. Taurine deficiency was not identified in GF dogs, and presence of congestive heart failure was not different between groups. Seven dogs that were reevaluated after diet change (6 received taurine supplementation) had clinical and echocardiographic improvement.

CONCLUSIONS

Dietary-associated DCM occurs with some GF diets and can improve with nutritional management, including diet change. The role of taurine supplementation, even without deficiency, is uncertain.

Oncolytic Viruses for Canine Cancer Treatment

Oncolytic virotherapy has been investigated for several decades and is emerging as a plausible biological therapy with several ongoing clinical trials and two viruses are now approved for cancer treatment in humans. The direct cytotoxicity and immune-stimulatory effects make oncolytic viruses an interesting strategy for cancer treatment. In this review, we summarize the results of in vitro and in vivo published studies of oncolytic viruses in different phases of evaluation in dogs, using PubMed and Google scholar as search platforms, without time restrictions (to date). Natural and genetically modified oncolytic viruses were evaluated with some encouraging results. The most studied viruses to date are the reovirus, myxoma virus, and vaccinia, tested mostly in solid tumors such as osteosarcomas, mammary gland tumors, soft tissue sarcomas, and mastocytomas. Although the results are promising, there are issues that need addressing such as ensuring tumor specificity, developing optimal dosing, circumventing preexisting antibodies from previous exposure or the development of antibodies during treatment, and assuring a reasonable safety profile, all of which are required in order to make this approach a successful therapy in dogs.

Changes in salivary analytes in canine parvovirus: A high-resolution quantitative proteomic study

The present study evaluated the changes in salivary proteome in parvoviral enteritis (PVE) in dogs through a high-throughput quantitative proteomic analysis. Saliva samples from healthy dogs and dogs with severe parvovirosis that survived or perished due to the disease were analysed and compared by Tandem Mass Tags (TMT) analysis. Proteomic analysis quantified 1516 peptides, and 287 (corresponding to 190 proteins) showed significantly different abundances between studied groups. Ten proteins were observed to change significantly between dogs that survived or perished due to PVE. Bioinformatics' analysis revealed that saliva reflects the involvement of different pathways in PVE such as catalytic activity and binding, and indicates antimicrobial humoral response as a pathway with a major role in the development of the disease. These results indicate that saliva proteins reflect physiopathological changes that occur in PVE and could be a potential source of biomarkers for this disease.

Observational Study Design in Veterinary Pathology, Part 1: Study Design

Observational studies are the basis for much of our knowledge of veterinary pathology and are highly relevant to the daily practice of pathology. However, recommendations for conducting pathology-based observational studies are not readily available. In part 1 of this series, we offer advice on planning and conducting an observational study with examples from the veterinary pathology literature. Investigators should recognize the importance of creativity, insight, and innovation in devising studies that solve problems and fill important gaps in knowledge. Studies should focus on specific and testable hypotheses, questions, or objectives. The methodology is developed to support these goals. We consider the merits and limitations of different types of analytic and descriptive studies, as well as of prospective vs retrospective enrollment. Investigators should define clear inclusion and exclusion criteria and select adequate numbers of study subjects, including careful selection of the most appropriate controls. Studies of causality must consider the temporal relationships between variables and the advantages of measuring incident cases rather than prevalent cases. Investigators must consider unique aspects of studies based on archived laboratory case material and take particular care to consider and mitigate the potential for selection bias and information bias. We close by discussing approaches to adding value and impact to observational studies. Part 2 of the series focuses on methodology and validation of methods.

Comparison of Different In Situ Hybridization Techniques for the Detection of Various RNA and DNA Viruses

In situ hybridization (ISH) is a technique to determine potential correlations between viruses and lesions. The aim of the study was to compare ISH techniques for the detection of various viruses in different tissues. Tested RNA viruses include atypical porcine pestivirus (APPV) in the cerebellum of pigs, equine and bovine hepacivirus (EqHV, BovHepV) in the liver of horses and cattle, respectively, and Schmallenberg virus (SBV) in the cerebrum of goats. Examined DNA viruses comprise canine bocavirus 2 (CBoV-2) in the intestine of dogs, porcine bocavirus (PBoV) in the spinal cord of pigs and porcine circovirus 2 (PCV-2) in cerebrum, lymph node, and lung of pigs. ISH with self-designed digoxigenin-labelled RNA probes revealed a positive signal for SBV, CBoV-2, and PCV-2, whereas it was lacking for APPV, BovHepV, EqHV, and PBoV. Commercially produced digoxigenin-labelled DNA probes detected CBoV-2 and PCV-2, but failed to detect PBoV. ISH with a commercially available fluorescent ISH (FISH)-RNA probe mix identified nucleic acids of all tested viruses. The detection rate and the cell-associated positive area using the FISH-RNA probe mix was highest compared to the results using other probes and protocols, representing a major benefit of this method. Nevertheless, there are differences in costs and procedure time.