Fatal tick-borne encephalitis virus infection in Dalmatian puppy-dogs after putative vector independent transmission

In a retrospective metatranscriptomics study, we identified tick-borne encephalitis virus (TBEV) to be the causative agent for a fatal non-suppurative meningoencephalitis in a three-week-old Dalmatian puppy in Switzerland. Further investigations showed that the two other littermates with similar signs and pathological lesions were also positive for TBEV. By using an unbiased approach of combining high-throughput sequencing (HTS) and bioinformatics we were able to solve the etiology and discover an unusual case of TBEV in three young puppies. Based on our findings, we suggest that a vector-independent transmission of TBEV occurred and that most likely an intrauterine infection led to the severe and fulminant disease of the entire litter. We were able to demonstrate the presence of TBEV RNA by in situ hybridization (ISH) in the brain of all three puppies. Furthermore, we were able to detect TBEV by RT-qPCR in total RNA extracted from formalin-fixed and paraffin embedded (FFPE) blocks containing multiple peripheral organs. Overall, our findings shed light on alternative vector-independent transmission routes of TBEV infections in dogs and encourage veterinary practitioners to consider TBEV as an important differential diagnosis in neurological cases in dogs.

[Five case reports on granulosa cell tumors in cattle with practical information on diagnosis and possible progression]

INTRODUCTION

Five cases of ovarian tumors (granulosa cell tumors) in cattle are presented from the patient load of the Vetsuisse University of Zurich and Bern. The aim of this work was to demonstrate the variable development of the illness and to indicate diagnostic and therapeutic possibilities to the practicing veterinarians. Case 1 shows bilateral appearance and the development of malignancy and metastases. The main symptoms in case 2 were the development of the mammary gland in a juvenile animal and the behavior modification due to a hormonal imbalance. The cases 3, 4 and 5 underwent surgery, case 4 restarted reproductive activity resulting in five subsequent pregnancies. The initial presumption is a result of a gynecological including ultrasonographic examination and can be verified by the analysis of Müllerian Inhibiting Hormone in serum. The decision to perform surgery should be done rapidly, as normal fertility can be achieved if the tumor is located unilaterally. Tumor growth and potential malignancy can provoke fatal health issues and also make it impossible to use meat of these animals for consumption.

Malignant catarrhal fever in a goat: manifestation of virus-induced erythema multiforme

Malignant catarrhal fever (MCF), caused by ovine herpesvirus 2 (OvHV2; Orthoherpesviridae, Macavirus ovinegamma2), has sheep as natural hosts. OvHV2 is an important macavirus globally that induces fatal disease in dead-end hosts. Goats, which can be infected subclinically with OvHV2, rarely develop MCF. A 28-wk-old female goat was presented with fever and multifocal crusty skin lesions. Histologic examination of a skin biopsy suggested erythema multiforme (EM), with pyoderma and dermal vasculitis. The doe was euthanized and subjected to postmortem and histologic examination. MCF was suspected and PCR assays for macaviruses were performed, followed by immunohistochemistry (IHC) for OvHV2 latency-associated nuclear antigen (oLANA), RNA in situ hybridization for Ov2.5 mRNA, and IHC to characterize infiltrating leukocytes. The main postmortem finding was severe multifocal ulcerative dermatitis with macrophage- and T cell-mediated arteritis. The latter was also detected in kidney, spleen, heart, and intestinal wall. The PCR assay detected high loads of OvHV2 in tissues. OvHV2 oLANA and Ov2.5 mRNA were expressed within the lesions in leukocytes, endothelial cells, fibroblasts, and/or keratinocytes. Our case confirms that MCF can initially manifest clinically as a skin disease in goats and as EM with confirmed viral etiology.

Virus discovery in dogs with non-suppurative encephalitis reveals a high incidence of tick-borne encephalitis virus infections in Switzerland

INTRODUCTION

Viral infections are a frequent cause of disseminated non-suppurative encephalitis in dogs. However, using routine diagnostic methods, the specific virus may remain unknown due to extensive or complete viral clearance or because the virus is unexpected or new. A metatranscriptomics-based approach of combining high-throughput sequencing (HTS) and bioinformatics analysis was used to investigate the viral etiology in archival cases of dogs with non-suppurative encephalitis. In formalin-fixed paraffin embedded (FFPE) brain material from the years 1976 to 2021 a high incidence of tick-borne encephalitis virus (TBEV) was detected. Moreover, canine distemper virus (CDV) was identified without typical demyelinating lesions and canine vesivirus (CaVV) was detected as an unexpected virus associated with non-suppurative encephalitis. We demonstrated the viral presence in brain tissues at the sites of inflammation by immunohistochemistry (IHC) and in situ hybridization (ISH). These results highlight the value of emerging sequencing technologies in veterinary diagnostics and expand our knowledge on the etiologies of encephalitis in dogs.

Independent COL17A1 Variants in Cats with Junctional Epidermolysis Bullosa

Epidermolysis bullosa (EB), characterized by defective adhesion of the epidermis to the dermis, is a heterogeneous disease with many subtypes in human patients and domestic animals. We investigated two unrelated cats with recurring erosions and ulcers on ear pinnae, oral mucosa, and paw pads that were suggestive of EB. Histopathology confirmed the diagnosis of EB in both cats. Case 1 was severe and had to be euthanized at 5 months of age. Case 2 had a milder course and was alive at 11 years of age at the time of writing. Whole genome sequencing of both affected cats revealed independent homozygous variants in COL17A1 encoding the collagen type XVII alpha 1 chain. Loss of function variants in COL17A1 lead to junctional epidermolysis bullosa (JEB) in human patients. The identified splice site variant in case 1, c.3019+1del, was predicted to lead to a complete deficiency in collagen type XVII. Case 2 had a splice region variant, c.769+5G>A. Assessment of the functional impact of this variant on the transcript level demonstrated partial aberrant splicing with residual expression of wildtype transcript. Thus, the molecular analyses provided a plausible explanation of the difference in clinical severity between the two cases and allowed the refinement of the diagnosis in the affected cats to JEB. This study highlights the complexity of EB in animals and contributes to a better understanding of the genotype-phenotype correlation in COL17A1-related JEB.

Cross-species evaluation of fibroblast activation protein alpha as potential imaging target for soft tissue sarcoma: a comparative immunohistochemical study in humans, dogs, and cats

Introduction

Complete surgical tumor resection is paramount in the management of soft tissue sarcoma (STS) in humans, dogs, and cats alike. Near-infrared targeted tracers for fluorescence-guided surgery (FGS) could facilitate intraoperative visualization of the tumor and improve resection accuracy. Target identification is complicated in STS due to the rarity and heterogeneity of the disease. This study aims to validate the expression of fibroblast activation protein alpha (FAP) in selected human, canine, and feline STS subtypes to assess the value of FAP as a target for FGS and to validate companion animals as a translational model.

Methods

Formalin-fixed and paraffin-embedded tissue samples from 53 canine STSs (perivascular wall tumor (PWT), canine fibrosarcoma (cFS), and STS not further specified (NOS)), 24 feline fibrosarcomas, and 39 human STSs (myxofibrosarcoma, undifferentiated pleomorphic sarcoma, dermatofibrosarcoma protuberans, and malignant peripheral nerve sheath tumor) as well as six canine and seven feline healthy controls and 10 inflamed tissue samples were immunohistochemically stained for their FAP expression. FAP labeling in tumor, peritumoral, healthy skin, and inflamed tissue samples was quantified using a visually assessed semiquantitative expression score and digital image analysis. Target selection criteria (TASC) scoring was subsequently performed as previously described.

Results

Eighty-five percent (85%) of human (33/39), 76% of canine (40/53), and 92% of feline (22/24) STSs showed FAP positivity in over 10% of the tumor cells. A high expression was determined in 53% canine (28/53), 67% feline (16/24), and 44% human STSs (17/39). The average FAP-labeled area of canine, feline, and human STSs was 31%, 33%, and 42%, respectively (p > 0.8990). The FAP-positive tumor area was larger in STS compared to healthy and peritumoral tissue samples (p < 0.0001). TASC scores were above 18 for all feline and human STS subtypes and canine PWTs but not for canine STS NOS and cFS.

Conclusion

This study represents the first cross-species target evaluation of FAP for STS. Our results demonstrate that FAP expression is increased in various STS subtypes compared to non-cancerous tissues across species, thereby validating dogs and cats as suitable animal models. Based on a TASC score, FAP could be considered a target for FGS.

Establishment of a Three-Dimensional In Vitro Model of Equine Papillomavirus Type 2 Infection

There is growing evidence that equine papillomavirus type 2 (EcPV2) infection is etiologically associated with the development of genital squamous cell carcinoma (SCC) and precursor lesions in equids. However, the precise mechanisms underlying neoplastic progression remain unknown. To allow the study of EcPV2-induced carcinogenesis, we aimed to establish a primary equine cell culture model of EcPV2 infection. Three-dimensional (3D) raft cultures were generated from equine penile perilesional skin, plaques and SCCs. Using histological, molecular biological and immunohistochemical methods, rafts versus corresponding natural tissue sections were compared with regard to morphology, presence of EcPV2 DNA, presence and location of EcPV2 gene transcripts and expression of epithelial, mesenchymal and tumor/proliferation markers. Raft cultures from perilesional skin harboring only a few EcPV2-positive (EcPV2+) cells accurately recapitulated the differentiation process of normal skin, whilst rafts from EcPV2+ penile plaques were structurally organized but showed early hyperplasia. Rafts from EcPV2+ SCCs exhibited pronounced hyperplasia and marked dysplasia. Raft levels of EcPV2 oncogene transcription (E6/E7) and expression of tumor/proliferation markers p53, Ki67 and MCM7 expression positively correlated with neoplastic progression, again reflecting the natural situation. Three-dimensional raft cultures accurately reflected major features of corresponding ex vivo material, thus constituting a valuable new research model to study EcPV2-induced carcinogenesis.

Murine tissue factor disulfide mutation causes a bleeding phenotype with sex specific organ pathology and lethality

Tissue factor is highly expressed in sub-endothelial tissue. The extracellular allosteric disulfide bond Cys186-Cys209 of human tissue factor shows high evolutionary conservation and in vitro evidence suggests that it significantly contributes to tissue factor procoagulant activity. To investigate the role of this allosteric disulfide bond in vivo, we generated a C213G mutant tissue factor mouse by replacing Cys213 of the corresponding disulfide Cys190-Cys213 in murine tissue factor. A bleeding phenotype was prominent in homozygous C213G tissue factor mice. Pre-natal lethality of 1/3rd of homozygous offspring was observed between E9.5 and E14.5 associated with placental hemorrhages. After birth, homozygous mice suffered from bleedings in different organs and reduced survival. Homozygous C213G tissue factor male mice showed higher incidence of lung bleedings and lower survival rates than females. In both sexes, C213G mutation evoked a reduced protein expression (about 10-fold) and severely reduced pro-coagulant activity (about 1000-fold). Protein glycosylation was impaired and cell membrane exposure decreased in macrophages in vivo. Single housing of homozygous C213G tissue factor males reduced the occurrence of severe bleeding and significantly improved survival, suggesting that inter-male aggressiveness might significantly account for the sex differences. These experiments show that the tissue factor allosteric disulfide bond is of crucial importance for normal in vivo expression, post-translational processing and activity of murine tissue factor. Although C213G tissue factor mice do not display the severe embryonic lethality of tissue factor knock-out mice, their postnatal bleeding phenotype emphasizes the importance of fully functional tissue factor for hemostasis.

Impact of high tidal volume ventilation on surfactant metabolism and lung injury in infant rats

The poorly understood tolerance toward high tidal volume (V_T) ventilation observed in critically ill children and age-equivalent animal models may be explained by surfactant homeostasis. The aim of our prospective animal study was to test whether high V_T with adequate positive end-expiratory pressure (PEEP) is associated with surfactant de novo synthesis and secretion, leading to improved lung function, and whether extreme mechanical ventilation affects intracellular lamellar body formation and exocytosis. Rats (14 days old) were allocated to five groups: nonventilated controls, PEEP 5 cmH₂O with V_T of 8, 16, and 24 mL/kg, and PEEP 1 cmH₂O with V_T 24 mL/kg. Following 6 h of ventilation, lung function, surfactant proteins and phospholipids, and lamellar bodies were assessed by forced oscillation technique, quantitative real-time polymerase chain reaction, mass spectrometry, immunohistochemistry, and transmission electron microscopy. High V_T (24 mL/kg) with PEEP of 5 cmH₂O improved respiratory system mechanics and was not associated with lung injury, elevated surfactant protein expression, or surfactant phospholipid content. Extreme ventilation with V_T 24 mL/kg and PEEP 1 cmH₂O produced a mild inflammatory response and correlated with higher surfactant phospholipid concentrations in bronchoalveolar lavage fluid without affecting lamellar body count and morphology. Elevated phospholipid concentrations in the potentially most injurious strategy (V_T 24 mL/kg, PEEP 1 cmH₂O) need further evaluation and might reflect accumulation of biophysically inactive small aggregates. In conclusion, our data confirm the resilience of infant rats toward high V_T-induced lung injury and challenge the relevance of surfactant synthesis, storage, and secretion as protective factors.

Paving the way for more precise diagnosis of EcPV2-associated equine penile lesions

Background

There is growing evidence that equine papillomavirus type 2 (EcPV2) infection is causally associated with the development of equine genital squamous cell carcinomas (SCCs). Early stages of disease present clinically as plaques or wart-like lesions which can gradually progress to tumoural lesions. Histologically these lesions are inconsistently described as benign hyperplasia, papilloma, penile intraepithelial neoplasia (PIN), carcinoma in situ (CIS) or SCC. Guidelines for histological classification of early SCC precursor lesions are not precisely defined, leading to potential misdiagnosis. The aim of this study was to identify histologic criteria and diagnostic markers allowing for a more accurate diagnosis of EcPV2-associated equine penile lesions.

Results

A total of 61 archived equine penile lesions were histologically re-assessed and classified as benign hyperplasia, papilloma, CIS or SCC. From these, 19 representative lesions and adjacent normal skin were comparatively analysed for the presence of EcPV2 DNA and transcripts using PCR and RNA in situ hybridisation (RISH). All lesional samples were positive by EcPV2 PCR and RISH, while adjacent normal skin was negative. RISH analysis yielded signal distribution patterns that allowed distinction of early (hyperplasia, papilloma) from late stage lesions (CIS, SCC). Subsequently, the 19 lesions were further assessed for expression of p53, Ki67, MCM7 and MMP1 by immunohistochemistry (IHC). All four proteins were expressed in both normal and lesional tissue. However, p53 expression was up-regulated in basal keratinocyte layers of papillomas, CIS and SCCs, as well as in upper keratinocyte layers of CIS and SCCs. MCM7 expression was only up-regulated in upper proliferating keratinocyte layers of papillomas, CIS and SCCs.

Conclusion

This study proposes combining a refined histological protocol for analysis of equine penile lesions with PCR- and/or RISH based EcPV2-screening and p53/MCM7 IHC to more accurately determine the type of lesion. This may help to guide the choice of optimum treatment strategy, especially at early stages of disease.

Non-invasive quantification of hepatic fat content in healthy dogs by using proton magnetic resonance spectroscopy and dual gradient echo magnetic resonance imaging

The objective of the present study was to describe two non-invasive methods for fat quantification in normal canine liver by using magnetic resonance imaging (MRI) and spectroscopy. Eleven adult beagle dogs were anesthetized and underwent magnetic resonance examination of the cranial abdomen by performing morphologic, modified Dixon (mDixon) dual gradient echo sequence, and proton magnetic resonance spectroscopy (¹H MRS) imaging. In addition, ultrasonographic liver examination was performed, fine-needle liver aspirates and liver biopsies were obtained, and hepatic triglyceride content was assayed. Ultrasonographic, cytologic, and histologic examination results were unremarkable in all cases. The median hepatic fat fraction calculated was 2.1% (range, 1.3%-5.5%) using mDixon, 0.3% (range, 0.1%-1.0%) using ¹H MRS, and 1.6% (range 1.0%-2.5%) based on triglyceride content. The hepatic fat fractions calculated using mDixon and ¹H MRS imaging were highly correlated to that based on triglyceride content. A weak correlation between mDixon and ¹H MRS imaging was detected. The results show that hepatic fat content can be estimated using non-invasive techniques (mDixon or ¹H MRS) in healthy dogs. Further studies are warranted to evaluate the use of these techniques in dogs with varying hepatic fat content and different hepatic disorders.

Cardiac-gated, phase contrast magnetic resonance angiography is a reliable and reproducible technique for quantifying blood flow in canine major cranial abdominal vessels

Blood flow changes in cranial abdominal vessels are important contributing factors for canine hepatic disease. This prospective, experimental, pilot study aimed to evaluate cardiac-gated, phase contrast magnetic resonance angiography (PCMRA) as a method for characterizing blood flow in canine major cranial abdominal vessels. Eleven, healthy, adult beagle dogs were sampled. Cardiac-gated, phase contrast magnetic resonance angiography of the cranial abdomen was performed in each dog and blood flow was independently measured in each of the major cranial abdominal vessels by three observers, with two observers recording blood flow values once and one observer recording blood flow values three times. Each dog then underwent ultrasonographic examination of the liver with fine needle aspirations and biopsies submitted to cytologic and histologic examination. The mean absolute stroke volume and velocity were respectively 9.6 ± 1.9 ml and -11.1 ± 1.1 cm/s for the cranial abdominal aorta, 2.1 ± 0.6 ml and -6.6 ± 1.9 cm/s for the celiac artery, and 2.3 ± 1.0 ml and -7.9 ± 3.1 cm/s for the cranial mesenteric artery. The mean absolute stroke volume and velocity were respectively 6.7 ± 1.3 ml and 3.9 ± 0.9 cm/s for the caudal vena cava and 2.6 ± 0.9 ml and 3.2 ± 1.2 cm/s for the portal vein. Intraobserver reliability was excellent (intraclass correlation coefficient > 0.9). Interobserver reproducibility was also excellent (intraclass correlation coefficient 0.89-0.99). Results of liver ultrasonography, cytology, and histopathology were unremarkable. Findings indicated that cardiac-gated, phase contrast magnetic resonance angiography is a feasible technique for quantifying blood blow in canine major cranial abdominal vessels. Blood flow values from this sample of healthy beagles can be used as background for future studies on canine hepatic disease.

Localized histiocytic sarcoma in a dog: an uncommon diagnosis in forelimb lameness

The clinical, ultrasonographic, arthrographic and histopathological aspects of a localized histiocytic sarcoma in the tendon sheath of the biceps brachii muscle in a Flat-Coated Retriever are described. An eight-year-old female Flat-Coated Retriever was referred for evaluation of chronic forelimb lameness. The orthopaedic examination revealed a painful shoulder joint. Ultrasonographic evaluation revealed distention of the tendon sheath of the biceps brachii muscle and the presence of multiple, hyperechoic structures in the distal portion of the sheath. The histological and immunohistochemical diagnosis of a biopsy taken during surgical exploration of the shoulder joint was histiocytic sarcoma. Palliative treatment with corticosteroids was administered but the dog was euthanized at the owner’s request four months following diagnosis due to progressing lameness. Post-mortem examination confirmed the diagnosis of histiocytic sarcoma without any evidence of metastases.

Idiopathic esophagopathies resembling gastroesophageal reflux disease in dogs

ObjectivePathologic gastroesophageal reflux (GER) has been demonstrated experimentally in dogs, and it is suspected to occur naturally in dogs, yet its clinical significance is unknown. The aim of the study was to demonstrate clinical indicators of pathologic GER in dogs with idiopathic esophagopathies. Materials and methods: Dogs with clinical signs suggestive for esophageal disease (regurgitation, ptyalism, or dysphagia) and where extraesophageal and specific esophageal diseases had been ruled out, were retrospectively diagnosed with idiopathic esophagopathies. History, physical examination findings, clinicopathologic, radiographic, and endoscopic data, and treatment results were obtained from medical records, reviewed and evaluated. Results: Out of 67 dogs with anamnestic esophageal signs, 12 (17.4%) dogs were identified as having idiopathic esophagopathies and were included in the study. Median age was 3.0 years (range 1.0–11.0), and median bodyweight was 28.2 kg (range 8.2–44.0). The most frequent anamnestic esophageal signs were ptyalism (10/12 dogs), regurgitation (8/12 dogs), signs of discomfort, pain (8/12 dogs), and cough (5/12 dogs). The most common radiographic abnormality was segmental esophageal dilation (8/12 dogs). Esophagoscopy revealed single mucosal surface defects at the gastroesophageal junction in 3/12 dogs. In dogs with altered esophageal motility, cytological and microbiological examinations of bronchial aspirates showed goblet cell hyperplasia (8/8 dogs), neutrophilic infiltration (5/8 dogs) and culturable bacteria (4/8 dogs), respectively. All dogs were treated with omeprazole (median 0.7 mg/kg once per day, range 0.5-1.2). Reported median treatment duration until remission of the main clinical signs was 20.0 days (range 8.0–54.0 days). This endpoint was reached in 11/12 dogs. Conclusion and clinical relevance: Results suggest that in some dogs with esophageal clinical signs, and where no primary disease could be identified, clinical indicators of pathologic GER such as pain, mucosal lesions and motility disturbances of the esophagus, respiratory complications, and response to therapy can be observed.

Zwei Fälle exfoliativer Dermatitis und Follikulitis bei Katzen mit histologischen Eigenschaften eines kutanen Lupus erythematodes

Gegenstand und Ziel: Diskussion klinischer, labordiagnostischer und histopathologischer Befunde zweier Katzen mit Verdacht auf kutanen Lupus erythematodes.

Material und Methode: Fallbericht zweier Katzen.

Ergebnisse: Zwei Katzen wurden dem Tierspital Zürich zur Abklärung einer exfoliativen Dermatitis vorgestellt. Histologisch lagen in beiden Fällen eine lymphozytenreiche Interface-Dermatitis, Apoptose der Keratinozyten und eine lymphozytäre murale Interface-Follikulitis vor. Kutane Arzneimittelnebenwirkungen, Erythema-multiforme-Komplex, thymomassoziierte Dermatitis und kutanes epitheliotropes Lymphom konnten ausgeschlossen werden. Als Ursache wurde ein kutaner Lupus erythematodes vermutet. Bei beiden Tieren ließen sich die Läsionen mit Cyclosporin A gut kontrollieren.

Schlussfolgerung: Eine exfoliative Dermatitis kann bei der Katze in Kombination mit einer muralen Follikulitis und Interface-Dermatitis auftreten. Diese Veränderungen sind mit der Diagnose eines kutanen Lupus erythematodes vereinbar.

Klinische Relevanz: Kutaner Lupus erythematodes ist in der Veterinärmedizin, vor allem bei Katzen, eine seltene Erkrankung und wurde noch nie in Assoziation mit einer exfoliativen Dermatitis beschrieben.

Validation of Tissue Microarrays for Immunohistochemical Analyses of Canine Lymphomas

In most validation studies of tissue microarrays (TMAs), a fixed number of cores with a given diameter are analyzed to determine the degree of accuracy by which the TMA represents the whole section. The statistical model described in the present study predicts this property for various combinations of 2 core sizes (0.6 mm and 1.2 mm) and different core numbers. The model was based on artificial TMA core biopsies generated from Ki-67 and active caspase-3 immunostains of 40 canine lymphoma samples. Positivity was scored on a continuous scale, and a large number of cells were analyzed with the help of semiautomated cell counting. Despite considerable differences in range and distribution of Ki-67 and active caspase-3 positivity values, the model predictions showed a high degree of agreement for both markers. Comparison of 0.6 mm and 1.2 mm cores indicated that the use of small cores necessitates inclusion of a larger number of samples but requires counting a markedly smaller number of cells. Suitability of TMAs to determine the immunophenotype of the whole section was assessed using 2 different combinations of core sizes and numbers. Both displayed a high degree of concordance with the whole section (κ0.6 = 0.79; κ1.2 = 0.91). The present study provides a basis for the use of TMAs in future high-throughput immunohistochemical investigations of selected markers in canine lymphomas. The statistical model presented can be used to determine an optimal TMA design depending on a desired accuracy.

Perfusion- and diffusion-weighted magnetic resonance imaging of the liver of healthy dogs

OBJECTIVE To describe the perfusion and diffusion characteristics of the liver in healthy dogs as determined by morphological, perfusion-weighted, and diffusion-weighted MRI. ANIMALS 11 healthy adult Beagles. PROCEDURES Each dog was anesthetized and underwent morphological, perfusion-weighted, and diffusion-weighted MRI of the cranial aspect of the abdomen. On the MRI images, a region of interest (ROI) was established for each of 6 structures (aorta, caudal vena cava, portal vein, hepatic parenchyma, splenic parenchyma, and skeletal [epaxial] muscle). The signal intensity was determined, and a time-intensity curve was generated for each ROI. The apparent diffusion coefficient (ADC) was calculated for the hepatic and splenic parenchyma in diffusion-weighted MRI images, and the normalized ADC for the liver was calculated as the ratio of the ADC for the hepatic parenchyma to the ADC for the splenic parenchyma. Dogs also underwent abdominal ultrasonography, and ultrasound-guided fine-needle aspirate samples and biopsy specimens were obtained from the liver for cytologic and histologic examination. RESULTS Cytologic and histologic results suggested that the liver was clinically normal in all dogs. Perfusion-weighted MRI parameters varied among the 6 ROIs. The mean ± SD ADC of the hepatic parenchyma was 0.84 × 10(-3) mm(2)/s ± 0.17 × 10(-3) mm(2)/s, and the mean normalized ADC for the liver was 1.8 ± 0.4. CONCLUSIONS AND CLINICAL RELEVANCE Results provided preliminary baseline information about the diffusion and perfusion characteristics of the liver in healthy dogs. Additional studies on dogs of various breeds with and without hepatopathies are necessary to validate and refine these findings.

Retroviral DNA--the silent winner: blood transfusion containing latent feline leukemia provirus causes infection and disease in naïve recipient cats

Background

The feline leukemia virus (FeLV) is a gamma-retrovirus of domestic cats that was discovered half a century ago. Cats that are infected with FeLV may develop a progressive infection resulting in persistent viremia, immunodeficiency, tumors, anemia and death. A significant number of cats mount a protective immune response that suppresses viremia; these cats develop a regressive infection characterized by the absence of viral replication and the presence of low levels of proviral DNA. The biological importance of these latter provirus carriers is largely unknown.

Results

Here, we demonstrate that ten cats that received a transfusion of blood from aviremic provirus carriers developed active FeLV infections, some with a progressive outcome and the development of fatal FeLV-associated disease. The infection outcome, disease spectrum and evolution into FeLV-C in one cat mirrored those of natural infection. Two cats developed persistent antigenemia; six cats were transiently antigenemic. Reactivation of infection occurred in some cats. One recipient developed non-regenerative anemia associated with FeLV-C, and four others developed a T-cell lymphoma, one with secondary lymphoblastic leukemia. Five of the ten recipient cats received provirus-positive aviremic blood, whereas the other five received provirus- and viral RNA-positive but aviremic blood. Notably, the cats that received blood containing only proviral DNA exhibited a later onset but graver outcome of FeLV infection than the cats that were transfused with blood containing proviral DNA and viral RNA. Leukocyte counts and cytokine analyses indicated that the immune system of the latter cats reacted quicker and more efficiently.

Conclusions

Our results underline the biological and epidemiological relevance of FeLV provirus carriers and the risk of inadvertent FeLV transmission via blood transfusion and demonstrate the replication capacity of proviral DNA if uncontrolled by the immune system. Our results have implications not only for veterinary medicine, such as the requirement for testing blood donors and blood products for FeLV provirus by sensitive polymerase chain reaction, but are also of general interest by revealing the importance of latent retroviral DNA in infected hosts. When aiming to eliminate a retroviral infection from a population, provirus carriers must be considered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-015-0231-z) contains supplementary material, which is available to authorized users.

Medial humeral epicondylitis in clinically affected cats

OBJECTIVE

To describe the clinical signs and histologic changes in cats clinically affected with medial humeral epicondylitis (MHE) and evaluate long-term outcome after either conservative or surgical treatment.

STUDY DESIGN

Prospective cohort study.

ANIMALS

Client-owned cats (n = 17) with MHE.

METHODS

Cats diagnosed with MHE, based on clinical signs, radiographs and computed tomography (CT), were prospectively recruited. Cats were treated conservatively for an initial 4 weeks, followed by either surgery or continued conservative treatment. Followup examinations were performed at 6 and 12 weeks and at 6-49 months.

RESULTS

Cats had a mean age of 10.3 years and presented for chronic lameness. Examination revealed pain on palpation caudodistal to the medial epicondyle and by exerting antebrachial supination/pronation with elbow and carpal flexion. Lameness was restricted to 1 limb although CT revealed bilateral disease in 11/17 cats. Free mineralized joint bodies were identified in 9/17 cats. Nine cats were treated surgically and 8 cats were treated conservatively. Intraoperative findings included new bone formation at the origin of the humeral head of the flexor carpi ulnaris muscle with displacement and adhesions of the ulnar nerve. Microscopic examination revealed neurogenic myopathy in 4/9 cats treated surgically. Seven of 9 cats treated surgically were free from lameness by 12 weeks. Seven of 8 cats treated conservatively were chronically lame throughout the study.

CONCLUSIONS

Cats with forelimb lameness should be evaluated for MHE. This condition is associated with free joint bodies and neurogenic myopathy. Surgical treatment is associated with excellent outcome in the majority of cats.

[Sacrocystis hjorti lesions in hunted red deer in Switzerland]

In meat samples from 2 hunted red deer (Cervus elaphus) of different origins (region Ilanz, region Filisur) large-scale greenish tissue discolorations with a gelatinous change of fascia were observed and diagnosed as eosinophilic fasciitis. Sarcocystis hjorti, a recently described Sarcocystis species in red deer and moose in Norway, was found as the causing agent. Foxes are regarded as final hosts in the development cycle of this parasite. Factors leading to such cases of eosinophilic fasciitis due to sarcosporidiosis, which is widespread in farm and wild ruminants and is normally inapparent are largely unknown. According to meat inspection directives carcasses with such discolorations have to be declared unfit for human consumption.

Vascular hamartoma in the central nervous system of a foal

Vascular hamartomas are non-neoplastic developmental anomalies of vessels. Cases of cerebral vascular hamartomas have been previously reported in dogs and cats. A 4-week-old Freiberger foal had shown persistent problems with breathing and swallowing since birth, and bilateral laryngeal paralysis was diagnosed. The foal subsequently developed left sided facial nerve paralysis and a secondary corneal ulcer in the left eye. Necropsy revealed a pinkish mass in the obex region of the brain. The mass was further investigated by histology and immunohistochemistry. Histologically, the mass consisted of many thin-walled, blood-filled vascular structures of variable diameter involving the white matter of the obex. The lining cells were immunohistochemically positive for factor VIII (von Willebrand factor) interpreted as endothelial cells. The endothelial lining showed also variable immunoreactivity for smooth muscle actin and vimentin. Normal neural parenchyma labeled with antibodies directed against glial fibrillary acidic protein and neuron-specific enolase was present between the vascular proliferations. A diagnosis of focal vascular hamartoma in the obex was made. The development of clinical signs is attributed to the compression of the surrounding neural parenchyma.

Patent ductus arteriosus in an adult cat with pulmonary hypertension and right-sided congestive heart failure: hemodynamic evaluation and clinical outcome following ductal closure

Right-sided congestive heart failure (CHF) developed secondary to severe pulmonary hypertension (PH) in an 8-year-old cat with a left-to-right shunting patent ductus arteriosus (PDA). Vascular reactivity was tested prior to shunt ligation by treatment with oxygen and sildenafil. This treatment was associated with a significant decrease in pulmonary artery pressure as assessed by echocardiography. Subsequently surgical shunt ligation was planned. During thoracotomy, digital occlusion of the PDA was performed for 10 min with simultaneous catheter measurement of right ventricular pressure, which did not increase. Permanent shunt ligation resulted in a complete and sustained clinical recovery. A lung biopsy sample obtained during thoracotomy demonstrated histopathological arterial changes typical of PH. Cats can develop clinically severe PH and right-sided CHF secondary to a left-to-right PDA even at an advanced age. Assuming there is evidence of pulmonary reactivity, PDA occlusion might be tolerated and can potentially produce long-term clinical benefits.

Clinical signs, treatment, and outcome in 15 cattle with sinonasal cysts

OBJECTIVE

To evaluate clinical signs, diagnosis, treatment and outcome of cattle with sinonasal cysts.

STUDY DESIGN

Case series.

ANIMALS

Cattle (n = 15).

METHODS

Medical records (2004-2011) of cattle with a fluid-filled mass in the nasal cavity, conchae, and/or paranasal sinuses were evaluated. Data retrieved and analyzed were reason of presentation, clinical signs, diagnostic techniques, surgical treatment, complications, and outcome.

RESULTS

Common presenting clinical signs were abnormal respiratory noise, nasal discharge, and abnormal respiratory effort. Mean age of affected cattle was 21.7 months. In 9 animals, cysts were identified by endoscopy. Radiographic signs included a mass in the paranasal sinuses or conchae (13), nasal septum deviation (12), fluid lines (10), and bone atrophy (5). Ten cattle were treated surgically with osteoplastic flap techniques to gain access to the frontal or maxillary sinus (5), nasal extraction of the cyst under endoscopic control (3) or a combination of both techniques (2). Nine cattle returned to be productive members of their herd and had no recurrence (mean follow-up, 20.7 months).

CONCLUSIONS

Sinonasal cysts should be considered as a primary differential diagnosis in cattle with abnormal respiratory noise, particularly in younger animals. Multiple cysts were common, which underlines the importance of a thorough preoperative examination using appropriate imaging modalities. Despite the often expansive nature of sinonasal cysts, the prognosis with surgical treatment was good.

A case in Europe of feline histoplasmosis apparently limited to the skin

BACKGROUND

Histoplasma capsulatum has a worldwide distribution, but reports in Europe remain rare. We present the second report of histoplasmosis in a cat in Europe and, to the best of our knowledge, the first case of feline histoplasmosis infection apparently limited to the skin.

CASE REPORT

A 6-year-old male castrated outdoor cat was presented to the dermatology service with a history of skin lesions evolving over 1 month and consisting of multiple papules and nodules on the head and neck. General examination was unremarkable. Cytological examination of the ulcerated nodules revealed a pyogranulomatous infiltrate, with numerous macrophages containing oval yeast-like cells, 2-5 μm in size, with a central, lightly basophilic core surrounded by a clear halo. A tentative diagnosis of fungal infection was made, and skin biopsy specimens were taken. Histological examination confirmed the cytology findings, and Grocott staining showed numerous organisms suggestive of Histoplasma within macrophages. Thoracic radiographs, abdominal ultrasound and routine laboratory testing were unremarkable. Fungal culture of a nodule was negative. PCR of total DNA extracted from the infected tissue and subsequent sequencing confirmed the diagnosis of H. capsulatum var. capsulatum. Surgical excision of the other nodules was performed, and the cat was treated with oral itraconazole 5 mg/kg once daily; 12 weeks after initial consultation, no lesions were visible. No recurrence was observed during an 8 month follow-up period.

CONCLUSIONS AND CLINICAL IMPORTANCE

Histoplasmosis should be included in the differential diagnosis of nodular diseases of cats worldwide.

Tissue sequestration of 'Candidatus Mycoplasma turicensis'

'Candidatus Mycoplasma turicensis' ('Candidatus M. turicensis') is a hemoplasma species that infects felids. It differs from other feline hemoplasma species due to its particular infection kinetics and phylogenetic similarity to rodent hemoplasma species. The lower and shorter bacteremia produced by 'Candidatus M. turicensis' suggests a possible tissue sequestration of the organism. The aim of this study was to explore this possibility. Five specified-pathogen free cats were subcutaneously inoculated with 'Candidatus M. turicensis' and sacrificed 86 days after inoculation. Thirty-one selected organs were collected upon necropsy, and samples were analyzed by real-time Taqman(®) PCR. The humoral immune response was monitored by DnaK ELISA. All five cats had detectable 'Candidatus M. turicensis' loads in the majority (52-100%) of the tested tissues. High 'Candidatus M. turicensis' tissue loads (average 3.46×10(4) copies/10 mg) were detected in the samples. The presence of the organisms in the tissues could not be explained by the blood burdens because the blood of four out of five cats tested PCR-negative at the time of necropsy. This is the first study to describe the distribution of 'Candidatus M. turicensis' in various organs; it also demonstrates that, in contrast to other feline hemoplasma species, significant sequestration of 'Candidatus M. turicensis' occurs in many tissues. These results represent an important step toward the understanding of the pathogenesis of 'Candidatus M. turicensis'.

Idiopathic esophagopathies resembling gastroesophageal reflux disease in dogs

OBJECTIVE

Pathologic gastroesophageal reflux (GER) has been demonstrated experimentally in dogs, and it is suspected to occur naturally in dogs, yet its clinical significance is unknown. The aim of the study was to demonstrate clinical indicators of pathologic GER in dogs with idiopathic esophagopathies.

MATERIALS AND METHODS

Dogs with clinical signs suggestive for esophageal disease (regurgitation, ptyalism, or dysphagia) and where extraesophageal and specific esophageal diseases had been ruled out, were retrospectively diagnosed with idiopathic esophagopathies. History, physical examination findings, clinicopathologic, radiographic, and endoscopic data, and treatment results were obtained from medical records, reviewed and evaluated.

RESULTS

Out of 67 dogs with anamnestic esophageal signs, 12 (17.4%) dogs were identified as having idiopathic esophagopathies and were included in the study. Median age was 3.0 years (range 1.0-11.0), and median bodyweight was 28.2 kg (range 8.2-44.0). The most frequent anamnestic esophageal signs were ptyalism (10/12 dogs), regurgitation (8/12 dogs), signs of discomfort, pain (8/12 dogs), and cough (5/12 dogs). The most common radiographic abnormality was segmental esophageal dilation (8/12 dogs). Esophagoscopy revealed single mucosal surface defects at the gastroesophageal junction in 3/12 dogs. In dogs with altered esophageal motility, cytological and microbiological examinations of bronchial aspirates showed goblet cell hyperplasia (8/8 dogs), neutrophilic infiltration (5/8 dogs) and culturable bacteria (4/8 dogs), respectively. All dogs were treated with omeprazole (median 0.7 mg/kg once per day, range 0.5-1.2). Reported median treatment duration until remission of the main clinical signs was 20.0 days (range 8.0-54.0 days). This endpoint was reached in 11/12 dogs.

CONCLUSION AND CLINICAL RELEVANCE

Results suggest that in some dogs with esophageal clinical signs, and where no primary disease could be identified, clinical indicators of pathologic GER such as pain, mucosal lesions and motility disturbances of the esophagus, respiratory complications, and response to therapy can be observed.

EcPV2 DNA in equine papillomas and in situ and invasive squamous cell carcinomas supports papillomavirus etiology

Equine penile papillomas, in situ carcinomas, and invasive carcinomas are hypothesized to belong to a continuum of papillomavirus-induced diseases. The former ones clinically present as small grey papules, while the latter 2 lesions are more hyperplasic or alternatively ulcerated. To test the hypothesis that these lesions are papillomavirus-induced, samples of 24 horses with characteristic clinical and histologic findings of penile papillomas or in situ or invasive squamous cell carcinomas were collected. As controls, 11 horses with various lesions--namely, Balanoposthitis (6 cases), melanoma (3 cases), follicular cyst (1 case), and amyloidosis (1 case)--were included. DNA was extracted and polymerase chain reaction applied to amplify papillomavirus DNA. The respective primers were designed to amplify DNA of the recently discovered equine papillomavirus EcPV2. All tested papilloma and squamous cell carcinoma samples were found to contain DNA of either of 2 previously published EcPV2 variants. Among the other samples 6 of 11 were found to contain EcPV2 DNA. To further support the findings and to determine where the papillomavirus DNA was located within the lesions, an in situ hybridization for the detection of EcPV2 DNA was established. The samples tested by this technique were found to clearly contain papillomavirus nucleic acid concentrated in the nucleus of the koilocytes. The findings of this study support previous data and the hypothesis that papillomaviruses induce the described penile lesions in horses.

Diagnostic exercise: Submucosal gastric masses in a cat

A 14-year-old neutered male cat presenting with chronic vomiting had 2 masses within the submucosa of the stomach that were excised. They presented histologically as circumscribed, submucosal masses consisting of diffusely arranged medium-sized round cells with a moderate amount of cytoplasm and interspersed eosinophils, separated by trabecular fibroblastic stroma. The overlying mucosa was diffusely infiltrated by the same round cells, and marked epitheliotropism was present. Neoplastic cells labelled positive for CD3 and negative for CD79a and CD117. Giemsa staining and silver staining (SNOBA) were also negative. A T-cell lymphoma with reactive fibroplasia was diagnosed, and differential diagnoses including mast cell tumor and feline gastrointestinal eosinophilic sclerosing fibroplasia could be excluded.

Orbito-nasal cyst in a young European short-haired cat

PURPOSE

To describe a case of an orbito-nasal cyst in a cat.

PROCEDURE

An 18-month-old male European short-haired cat was presented to the Ophthalmology service of the Vetsuisse Faculty, University of Zurich for a subcutaneous swelling in the medial canthal region of the right eye (OD). Ophthalmologic, ultrasound and CT examinations, and fine needle aspiration were performed. After lesion excision, the removed tissue was submitted for histopathology. CT examination was repeated 5 months after removal of the cyst.

RESULTS

Ophthalmologic examination revealed a large fluctuant swelling inferonasal to OD. Despite patent lacrimal puncta, only the first few mm of the lacrimal canaliculi could be cannulated. A normal globe with moderate enophthalmos was present. Ultrasound examination showed a well-defined lobulated cyst-like structure in the right orbit, inferonasal and anterior to the eye. CT examination revealed extension of this lesion through the medial orbital wall into the right nasal cavity. Fine needle aspiration confirmed the cystic nature of the lesion. An orbito-nasal cyst was diagnosed. The orbital part of the cyst was dissected from the surrounding tissue and excised from the periosteum in the medial orbital wall defect. Part of the maxillary bone was removed to allow removal of the cyst from the nasal cavity. Histologically, the cyst wall consisted of a single to multilayered, mostly cuboidal epithelium and surrounding connective tissue. Follow-up revealed a good functional result and no recurrence 7 months after cyst removal.

CONCLUSIONS

Similar orbito-nasal cystic structures were reported in dogs but not in cats.

Massive haematoma formation associated with proximal popliteal artery haemangioendothelioma in a dog

A mixed breed dog presented with diffuse unilateral hind limb swelling, which ultrasound and cytology confirmed to be caused by severe haematoma formation. Multi-detector computed tomography (MDCT) angiography allowed distinct visualisation of an anomalous segment of the proximal popliteal artery, the presumed origin of the self-sustaining haematoma. Histopathology classified the malformed vessel as a haemangioendothelioma, a neoplasia of intermediate malignancy. Considering this as differential diagnosis to a neoplastic vascular alteration of high malignancy (such as haemangiosarcoma) might alter choice of treatment in future cases with similar clinical and imaging findings.

[Conjunctival changes in a Swiss Braunvieh heifer with malignant lymphoma]

This report describes a 2.8-year-old Swiss Braunvieh heifer with conjunctival changes as the lead clinical signs of malignant lymphoma. The heifer was referred to our clinic because of conjunctivitis that did not respond to treatment with antibiotics. The patient had bilateral lacrimation, severe swelling of the third eyelids and prolapse of the conjunctivae, which were erythematous and covered with haemorrhagic crusts. A clinical examination revealed enlarged prescapular and prefemoral lymph nodes. Based on cytological examination of a fine needle aspirate from a prescapular lymph node, a tentative diagnosis of malignant lymphoma was made. The heifer was euthanased and a postmortem examination carried out. The conjunctival lesions consisted of diffuse multifocal nodules of varying size. There was generalised lymphadenopathy and beige nodules were seen in several internal organs. Histological and immunohistological examinations confirmed the diagnosis of multicentric leukosis characterised by T-cell lymphoblasts, which had also infiltrated the conjunctivae. Examination of a blood sample for enzootic bovine leukosis virus yielded a negative result.