Myosin heavy-chain myopathy in 2 American quarter horses

A 1.5-year-old American quarter horse gelding (case 1) and an 11-month-old American quarter horse filly (case 2) were presented for acute onset pelvic lameness and lethargy. Case 1 had nasal discharge, while case 2 developed rapid muscle atrophy. Both horses had elevated serum creatine kinase activity. The horses showed similar polyphasic histiocytic and lymphoplasmacytic myositis with necrosis, mineralization, and regeneration. Additionally, case 1 had Streptococcus equi subsp. equi-induced suppurative retropharyngeal lymphadenitis with renal purpura hemorrhagica and myoglobinuric nephropathy. A focal pulmonary abscess caused by Actinobacillus equuli was found in case 2. Genetic testing revealed case 1 as heterozygous and case 2 as homozygous for the E321G MYH1 variant, supporting the diagnosis of myosin heavy-chain myopathy, with concomitant bacterial disease as potential triggers.

Common superficial and deep cutaneous bacterial infections in domestic animals: A review

The skin covers the external surface of animals, and it is constantly exposed to and inhabited by different microorganisms, including bacteria. Alterations in the skin barrier allow commensal and/or pathogenic bacteria to proliferate and penetrate deep into the lower layers of the skin. Being the first barrier to the external environment, the skin is prone to injuries, allowing the penetration of microorganisms that may lead to severe deep infections. Companion animals, especially dogs, are prone to bacterial infections, often secondary to allergic dermatitis. When environmental conditions are unfavorable, horses, cattle, sheep, and goats can develop superficial infections, such as those caused by Dermatophilus congolensis. Deep inflammation is commonly caused by Mycobacterium spp., which results in granulomatous to pyogranulomatous dermatitis and panniculitis. Likewise, bacteria such as Nocardia spp. and Actinomyces spp. can cause deep pyogranulomatous inflammation. Bacteria that lead to deep necrotizing lesions (eg, necrotizing fasciitis/flesh-eating bacteria) can be severe and even result in death. This review includes an overview of the most common cutaneous bacterial infections of domestic animals, highlighting the main features and histologic morphology of the bacteria, cutaneous structures involved, and the type of inflammatory infiltrates.

Reassessing Stephanofilaria stilesi dermatitis in cattle, with characterization of molecular markers for confirming diagnosis

BACKGROUND

Stephanofilaria stilesi is a vector-borne filarioid nematode of cattle in North America that is transmitted via the hematophagous horn fly (Haematobia irritans) intermediate host. Despite being relatively common, little attention has been given to a thorough description of S. stilesi lesions and the potential integration of pathological and molecular diagnostic findings to confirm infection.

METHODS

To characterize the cutaneous lesions caused by S. stilesi in cattle (Bos taurus taurus and Bos taurus indicus), skin of the ventral abdominal midline was collected from 22 animals during postmortem examination. Skin samples were processed for histology, transmission electron microscopy (TEM), DNA extraction, PCR, and Sanger sequencing targeting molecular markers cytochrome oxidase c subunit 1 (cox1), 12S, 18S rDNA, and 28S rDNA.

RESULTS

Macroscopically, lesions ranged from 5 × 4 cm to 36 × 10 cm, consisting of one large single lesion, or two to four ovoid areas at the ventral abdominal midline, surrounding the umbilicus. Each lesion presented as ulcerative dermatitis with dry, serocellular crusts, or alopecic and lichenified areas. Histologically, eosinophilic, neutrophilic, and ulcerative dermatitis with furunculosis, folliculitis, and epidermal hyperplasia was observed. Cross sections of adult nematodes were identified in ~ 60% of the cases (n = 13) within intact follicles, sebaceous ducts, crusts, and areas of furunculosis. Stephanofilaria first-stage larvae (L1) were observed in five cases within "vitelline membranes" in the superficial dermis and crusts. Ultrastructurally, the L1 cross sections were compounded of smooth multilayered cuticle and somatic cells. The "vitelline membrane" is a tri-layered membrane where L1 are suspended in a matrix. Stephanofilaria stilesi DNA was found in 5 out of the 13 cases in which adults or L1 were histologically observed (38%) and in 1 out of the 9 cases without adults or L1 present (11%). Phylogenetic analyses suggest a closer relationship of the genus Stephanofilaria with Thelazioidea, instead of the family Filariidae (Filarioidea), in which it has been historically allocated.

CONCLUSIONS

Our study improved the characterization of lesions and described ultrastructural findings of S. stilesi and highlights that molecular tools should be utilized in combination with histology for improved diagnostic resolution.

Case report: Hemangioblastoma in the brainstem of a dog

A 3-year-old castrated male, American Pit Bull Terrier presented to Texas A&M University due to a 3-week mixed cerebellar and general proprioceptive ataxia, circling, head tilt, and dull mentation. Neurologic examination revealed signs of vestibular and mesencephalic dysfunction. Postmortem examination revealed a 1.1 × 1 × 0.8-cm, soft, dark red, well-circumscribed, left-sided mass, extending from the crus cerebri of the midbrain caudally to the pons. Microscopically, the neoplasm was composed of a spindle-shaped interstitial population of cells interspersed between a prominent capillary network, consistent with the reticular pattern of hemangioblastoma. Interstitial cells had strong, diffuse, intracytoplasmic immunolabeling for neuron-specific enolase (NSE) and were variably positive for intracytoplasmic glial fibrillary acidic protein (GFAP). Vascular endothelial cells had strong diffuse, intracytoplasmic immunolabeling for von Willebrand factor (VWF) glycoprotein. To date, only six cases of hemangioblastoma have been reported in canines, five in the spinal cord, and one in the rostral cerebrum. Our case may represent the first canine hemangioblastoma localized to the brainstem.

Systemic proliferative arteriopathy and hypophysitis in a cow with chronic ovine herpesvirus 2-induced malignant catarrhal fever

Malignant catarrhal fever (MCF) is a severe, systemic, lymphoproliferative disease affecting domestic ruminants, caused by a group of MCF viruses in the genus Macavirus. Infection of cattle and bison with ovine herpesvirus 2 (OvHV2) is economically significant in North America. Sheep are the reservoir host of the virus, and only rarely manifest disease. Cattle and bison, however, frequently have lymphoproliferation, mucosal ulceration, and systemic vasculitis. OvHV2-induced MCF in cattle and bison is often fatal, with clinical recovery reported only rarely. Chronic cases are uncommon, but vascular changes of variable severity and ocular lesions have been described. Here we present a case of chronic MCF in a cow with proliferative arteriopathy, systemic vasculitis, and OvHV2-associated hypophysitis. We demonstrated OvHV2 nucleic acid in affected tissues with in situ hybridization.

Effect of chronic and acute enterotoxigenic E. coli challenge on growth performance, intestinal inflammation, microbiome, and metabolome of weaned piglets

Post-weaning enteropathies in swine caused by pathogenic E. coli, such as post-weaning diarrhea (PWD) or edema disease (ED), remain a significant problem for the swine industry. Reduction in the use of antibiotics over concerns of antibiotic resistance and public health concerns, necessitate the evaluation of effective antibiotic alternatives to prevent significant loss of livestock and/or reductions in swine growth performance. For this purpose, an appropriate piglet model of pathogenic E. coli enteropathy is required. In this study, we attempted to induce clinical signs of post-weaning disease in a piglet model using a one-time acute or lower daily chronic dose of a pathogenic E. coli strain containing genes for both heat stable and labile toxins, as well as Shiga toxin. The induced disease state was monitored by determining fecal shedding and colonization of the challenge strain, animal growth performance, cytokine levels, fecal calprotectin, histology, fecal metabolomics, and fecal microbiome shifts. The most informative analyses were colonization and shedding of the pathogen, serum cytokines, metabolomics, and targeted metagenomics to determine dysbiosis. Histopathological changes of the gastrointestinal (GI) tract and tight junction leakage as measured by fecal calprotectin concentrations were not observed. Chronic dosing was similar to the acute regimen suggesting that a high dose of pathogen, as used in many studies, may not be necessary. The piglet disease model presented here can be used to evaluate alternative PWD treatment options.

Immunophenotype of the inflammatory response in the central and enteric nervous systems of cockatiels (Nymphicus hollandicus) experimentally infected with parrot bornavirus 2

Proventricular dilatation disease is a lethal disease of psittacine birds. In this study, we characterized the local cellular immune response in the brain, proventriculus, and small intestine of 27 cockatiels (Nymphicus hollandicus) experimentally infected with parrot bornavirus 2 (PaBV-2). Perivascular cuffs in the brain were composed of CD3+ T-lymphocytes and Iba1+ macrophages/microglia in most cockatiels (n = 26). In the ganglia of the proventriculus, CD3+ T-lymphocytes (n = 17) and Iba1+ macrophages (n = 13) prevailed. The ganglia of the small intestine had a more homogeneous distribution of these leukocytes, including PAX5+ B-lymphocytes (n = 9), CD3+ T-lymphocytes (n = 8), and Iba1+ macrophages (n = 8). Our results indicate that perivascular cuffs in the brain and the inflammatory infiltrate in the proventriculus of PaBV-2-infected cockatiels is predominately composed of T-lymphocytes, while the inflammatory infiltrates in the ganglia of the small intestine are characterized by a mixed infiltrate composed of T-lymphocytes, B-lymphocytes, and macrophages.

Host genetic diversity drives variable central nervous system lesion distribution in chronic phase of Theiler's Murine Encephalomyelitis Virus (TMEV) infection

Host genetic background is a significant driver of the variability in neurological responses to viral infection. Here, we leverage the genetically diverse Collaborative Cross (CC) mouse resource to better understand how chronic infection by Theiler's Murine Encephalomyelitis Virus (TMEV) elicits diverse clinical and morphologic changes in the central nervous system (CNS). We characterized the TMEV-induced clinical phenotype responses, and associated lesion distributions in the CNS, in six CC mouse strains over a 90 day infection period. We observed varying degrees of motor impairment in these strains, as measured by delayed righting reflex, paresis, paralysis, seizures, limb clasping, ruffling, and encephalitis phenotypes. All strains developed neuroparenchymal necrosis and mineralization in the brain, primarily localized to the hippocampal regions. Two of the six strains presented with axonal degeneration with myelin loss of the nerve roots in the lumbar spinal cord. Moreover, we statistically correlated lesion distribution with overall frequencies of clinical phenotypes and phenotype progression to better understand how and where TMEV targets the CNS, based on genetic background. Specifically, we assessed lesion distribution in relation to the clinical progression of these phenotypes from early to late TMEV disease, finding significant relationships between progression and lesion distribution. Finally, we identified quantitative trait loci associated with frequency of lesions in a particular brain region, revealing several loci of interest for future study: lysosomal trafficking regulator (Lyst) and nidogen 1 (Nid1). Together, these results indicate that the genetic background influences the type and severity of clinical phenotypes, phenotypic resilience to TMEV, and the lesion distribution across strains.

Reproductive tract neoplasia in adult female Asian elephants (Elephas maximus)

Recent reports have highlighted a lower-than-expected prevalence of neoplasia in elephants and suggested mechanisms for cancer resistance. But despite infrequent reports in the literature, uterine neoplasia is common in managed Asian elephants (Elephas maximus). This study is an archival review of reproductive tract neoplasia in 80 adult female Asian elephant mortalities in managed care facilities in the United States from 1988 to 2019. Neoplasms occurred in 64/80 (80%) of cases. Most were in the uterus (63/64; 98%) with only a single case of ovarian neoplasia. Myometrial leiomyomas were present in 57/63 (90%) cases with uterine neoplasia. Uterine adenocarcinoma was present in 8/63 (13%) cases. Remaining cases included endometrial adenoma (2), focal carcinoma in situ in endometrial polyps (1), anaplastic carcinoma (1), endometrial hemangioma (1), primitive neuroectodermal tumor (PNET; 1), and angiosarcoma (1). One case with uterine adenocarcinoma had a separate pelvic mass histologically characterized as an anaplastic sarcoma. Distant metastases were documented in 5/8 (63%) cases of uterine adenocarcinoma, and in the uterine anaplastic carcinoma, PNET, and angiosarcoma. Four uterine adenocarcinomas and one carcinoma in situ were examined immunohistochemically for pan-cytokeratin, vimentin, and estrogen receptor. In all, neoplastic cells were pan-cytokeratin positive and vimentin negative, and in 2 cases were immunoreactive for estrogen receptor. Results show that female reproductive tract neoplasia, particularly of the uterus, is common in Asian elephants and is not limited to leiomyomas. Importantly, uterine neoplasms have the potential to impact fecundity and may represent obstacles to conservation in managed care.

Comparison of 2 fixatives in the porcine colon for in situ microbiota studies

Fixation is the first step towards preservation of tissues and can impact downstream histological applications. Historically, formalin has been the fixative of choice in both research and clinical settings due to cost, accessibility, and broad applicability. Here, we describe a method for collection of porcine colon, and compare the usage of Carnoy's solution (CS) to a 10% neutral buffered formalin (NBF) in tissue fixation. Consecutive colon samples were collected from 24 four-wk-old piglets and fixed in CS for 45 min or NBF for 24 h. We measured the thickness of the inner mucus layer using Alcian Blue stain and found thicker inner mucus layers in porcine colons fixed with CS as compared to NBF (P < 0.0001). Carnoy's solution-fixed colon exhibited greater bacterial cell counts than NBF-fixed colon (P < 0.0022) after labeling with an eubacterial probe in fluorescent in situ hybridization (FISH). No difference was observed between the mucosal height (P = 0.42) and number of goblet cells (P = 0.66) between the 2 fixatives. From this, we concluded CS is more suitable than NBF for the preservation of the mucus layer and the associated mucosal bacteria in the porcine colon without compromising on overall tissue morphology. This study provides a useful sampling and fixation methodology for histology studies in the porcine gastrointestinal tract, and may be beneficial to microbiota, pathology, and nutrition studies.

Bacterial Biogeography of the Colon in Dogs With Chronic Inflammatory Enteropathy

The intestinal microbiota is believed to play a role in the pathogenesis of inflammatory bowel disease in humans and chronic inflammatory enteropathy (CIE) in dogs. While most previous studies have described the gut microbiota using sequencing methods, it is fundamental to assess the spatial distribution of the bacteria for a better understanding of their relationship with the host. The microbiota in the colonic mucosa of 22 dogs with CIE and 11 control dogs was investigated using fluorescence in situ hybridization (FISH) with a universal eubacterial probe (EUB338) and specific probes for select bacterial groups. The number of total bacteria labeled with EUB338 probe was lower within the colonic crypts of dogs with CIE compared to controls. Helicobacter spp. and Akkermansia spp. were decreased on the colonic surface and in the crypts of dogs with CIE. Dogs with CIE had increased number of Escherichia coli/Shigella spp. on the colonic surface and within the crypts compared to control dogs. In conclusion, the bacterial microbiota in the colonic mucosa differed between dogs with and without CIE, with depletion of the crypt bacteria in dogs with CIE. The crypt bacterial species that was intimately associated with the host mucosa in control dogs was composed mainly of Helicobacter spp.

Cardiac Lesions of Natural and Experimental Infection by Parrot Bornaviruses

Lymphoplasmacytic inflammation associated with bornavirus N protein occurs in the epicardial ganglia, myocardium and endocardium of birds diagnosed with proventricular dilatation disease (PDD). These pathological findings suggest that sudden death in psittacine birds might stem from cardiac compromise due to parrot bornavirus (PaBV) infection. Therefore, we investigated cardiac lesions in cases of PDD, searching databases from 1988 to 2019, and reviewed three experimental studies of PaBV infection. Fifty cases of PDD in birds infected naturally with PaBV and 27 cases of PDD in birds infected experimentally with PaBV (all having descriptions of inflammatory cardiac lesions) were reviewed. For each case, five regions of the heart were evaluated by light microscopy and immunohistochemistry (IHC). These regions were the epicardial ganglia/nerves, the endocardium, the myocardium, the Purkinje fibres and the great vessels. Sudden death was documented in 17/50 naturally infected cases, while 23/50 had digestive signs, and only 12/50 had neurological signs. Grossly, only five naturally-infected and five experimentally-infected cases had cardiomegaly or hydropericardium. Epicardial ganglioneuritis was the most consistent microscopical finding in natural (46/50) and experimental cases (26/27), followed by myocarditis (34/50) for naturally-infected and endocarditis for experimentally-infected birds (6/27). PaBV-2 antigen was detected most frequently by IHC in the epicardial ganglia (54/77) compared with the other tissues. This retrospective study demonstrates the presence of PaBV protein and inflammation in the heart of birds infected with PaBV and suggests a link between PaBV and cardiac disease and sudden death in psittacine birds.

Retrospective Analysis of Aetiological Agents Associated with Pulmonary Mycosis Secondary to Enteric Salmonellosis in Six Horses by Panfungal Polymerase Chain Reaction

Pulmonary mycosis secondary to enterocolitis is an uncommon diagnosis in equine medicine, but is thought to result from mucosal compromise and translocation of enteric fungi. The aetiological agent associated with translocation is often identified based on fungal culture or hyphal features in histological sections. In order to understand better the aetiological agents involved, six horses diagnosed with Salmonella enteritis and concurrent pulmonary mycosis were identified retrospectively through a database search of veterinary teaching hospital records. Samples from these cases were subjected to polymerase chain reaction and sequencing of the internal transcribed spacer 2 (ITS-2) located between the 5.8S and 28S rRNA genes to identify the aetiological agent involved. Sequencing identified Aspergillus fumigatus, Aspergillus flavus, Fusarium spp., Cladosporium spp. and Curvularia spp. A single case had a dual infection with Fusarium spp. and A. fumigatus.

Persistent Organic Pollutants in Livers and Hg in Feathers of Neotropic Cormorants (Phalacrocorax brasilianus) from the Trinity River Watershed (Texas, USA)

The Trinity River (Texas, USA) has been historically known as a polluted river because of its proximity to the Dallas-Fort Worth area and because of known discharges of sewage and agricultural irrigation waters to the river. Surprisingly, there are no studies regarding the presence of legacy contaminants in the river and their impacts to wildlife. The objectives of this study were to determine accumulation and potential impacts of persistent organic pollutants, such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), on Neotropic cormorants (Phalacrocorax brasilianus) nesting along the Trinity River. Adult and first-year cormorants were collected from two sites on the Trinity River Watershed during 2014 and 2015. Tissue sections from liver, spleen, kidneys, and gonads were used for histopathology analysis, and a portion of the liver was analyzed for OCPs, PCBs, and PBDEs. Breast feathers were analyzed for Hg. Surprisingly, all the contaminants were present at low concentrations, p,p'-DDE (2-724 ng/g ww), PCBs (28-851 ng/g ww), PBDEs (1-85 ng/g ww), Hg (1.9-3.4 µg/g dw), and below those that could be associated with adverse effects. Also, histological analysis of liver and kidney samples did not reveal morphologic changes consistent with acute or chronic toxicosis. The majority of the histologic changes were inflammatory and were related to parasitic infestation. Our results suggest that aquatic birds using the Trinity River watershed are not at risk for adverse effects due to the contaminants studied. These results should be useful to wildlife managers regarding concerns over contaminant impacts on wildlife of the Trinity River.

Hereditary xanthinuria in a goat

A 2-year-old mixed breed goat was presented for a 1-day history of anorexia and 1 week of weight loss. Serum biochemistry disclosed severe azotemia. Abdominal ultrasound examination showed decreased renal corticomedullary distinction, poor visualization of the renal pelves, and dilated ureters. On necropsy, the kidneys were small, the pelves were dilated, and the medulla was partially effaced by variably sized yellow nephroliths. Histologically, cortical and medullary tubules were distended by yellow-brown, multilayered crystals. Stone composition was 100% xanthine. Exonic sequencing of xanthine dehydrogenase (XDH) and molybdenum cofactor sulfurase (MOCOS) identified 2 putative pathogenic variants: a heterozygous XDH p.Leu128Pro variant and a homozygous MOCOS p.Asp303Gly variant. Variant frequencies were determined in 7 herd mates, 12 goats undergoing necropsy, and 443 goats from genome databases. The XDH variant was not present in any of these 462 goats. The MOCOS variant allele frequency was 0.03 overall, with 3 homozygotes detected. Hereditary xanthinuria is a recessive disorder in other species, but the XDH variant could be causal if the case goat is a compound heterozygote harboring a second variant in a regulatory region not analyzed or if the combination of the XDH and MOCOS variants together abolish XDH activity. Alternatively, the MOCOS variant alone could be causal despite the presence of other homozygotes, because hereditary xanthinuria in humans often is asymptomatic. Ours is the first report describing the clinical presentation and pathology associated with xanthine urolithiasis in a goat. The data support hereditary xanthinuria, but functional studies are needed to conclusively determine the causal variant(s).

Comparison of intestinal expression of the apical sodium-dependent bile acid transporter between dogs with and without chronic inflammatory enteropathy

BACKGROUND

Intestinal absorption of bile acids is mediated by the apical sodium-dependent bile acid transporter (ASBT). Fecal bile acid dysmetabolism has been reported in dogs with chronic inflammatory enteropathy (CIE).

OBJECTIVE

Characterization of ASBT distribution along the intestinal tract of control dogs and comparison to dogs with CIE.

ANIMALS

Twenty-four dogs with CIE and 11 control dogs.

METHODS

The ASBT mRNA and protein expression were assessed using RNA in situ hybridization and immunohistochemistry, respectively. The concentrations of fecal bile acids were measured by gas chromatography-mass spectrometry. The fecal microbiota dysbiosis index was assessed with a quantitative polymerase chain reaction panel.

RESULTS

In control dogs, ASBT mRNA expression was observed in enterocytes in all analyzed intestinal segments, with highest expression in the ileum. The ASBT protein expression was restricted to enterocytes in the ileum, cecum, and colon. Dogs with CIE had significantly decreased expression of ASBT protein in the ileum (P = .001), which was negatively correlated with histopathological score (ρ = -0.40; Pcorr = .049). Additionally, dogs with CIE had a significantly increased percentage of primary bile acids in feces compared to controls (P = .04). The fecal dysbiosis index was significantly higher in dogs with CIE than in control dogs (P = .01).

CONCLUSIONS AND CLINICAL IMPORTANCE

These findings indicate that ileal protein expression of ASBT is downregulated in dogs with CIE. This change may be linked to the inflammatory process, intestinal dysbiosis, and fecal bile acid dysmetabolism observed in these patients.

Distribution of Viral Antigen and Inflammatory Lesions in the Central Nervous System of Cockatiels ( Nymphicus hollandicus) Experimentally Infected with Parrot Bornavirus 2

Neurotropism is a striking characteristic of bornaviruses, including parrot bornavirus 2 (PaBV-2). Our study evaluated the distribution of inflammatory foci and viral nucleoprotein (N) antigen in the brain and spinal cord of 27 cockatiels ( Nymphicus hollandicus) following experimental infection with PaBV-2 by injection into the pectoral muscle. Tissue samples were taken at 12 timepoints between 5 and 114 days post-inoculation (dpi). Each experimental group had approximately 3 cockatiels per group and usually 1 negative control. Immunolabeling was first observed within the ventral horns of the thoracic spinal cord at 20 dpi and in the brain (thalamic nuclei and hindbrain) at 25 dpi. Both inflammation and viral antigen were restricted to the central core of the brain until 40 dpi. The virus then spread quickly at 60 dpi to both gray and white matter of all analyzed sections of the central nervous system (CNS). Encephalitis was most severe in the thalamus and hindbrain, while myelitis was most prominent in the gray matter and equally distributed in the cervical, thoracic, and lumbosacral spinal cord. Our results demonstrate a caudal to rostral spread of virus in the CNS following experimental inoculation of PABV-2 into the pectoral muscle, with the presence of viral antigen and inflammatory lesions first in the spinal cord and progressing to the brain.

Distribution of bile acid receptor TGR5 in the gastrointestinal tract of dogs

Takeda-G-protein-receptor-5 (TGR5) is a receptor for bile acids and its expression has been described in a variety of tissues and species. Characterization of TGR5 distribution and function has been investigated in drug discovery for the treatment of metabolic diseases in humans. Because dogs are one of the species used in biomedical research and share some similarities with human gastrointestinal diseases, the objective of this study was to characterize the distribution of TGR5 receptor in the canine species. This study characterizes the distribution of TGR5 receptor in the gastrointestinal tract, liver, gallbladder, and pancreas of 8 dogs. The distribution of TGR5 antigen and mRNA expression was investigated using immunohistochemistry and RNA in situ hybridization, respectively. TGR5 immunolabeling was located in the cell membrane or in the cell membrane and cytoplasm. TGR5 immunolabeling was broadly distributed in macrophages, endothelial cells, ganglion cells, and leiomyocytes throughout all the examined tissues. Epithelial cells from tongue, stomach to rectum, as well as from gallbladder, biliary and pancreatic ducts demonstrated TGR5 immunolabeling. In endocrine cells, TGR5 immunolabeling was observed in intestinal enteroendocrine cells and islets of Langerhans in the pancreas. The hepatocytes had a unique pattern of immunolabeling located on the canalicular surface of the cell membrane. TGR5 mRNA expression was located mainly in the nucleus and the only negative cells throughout all examined tissues were striated muscle from tongue and esophagus, muscularis mucosae, esophageal glands, and hepatic sinusoids. These findings indicate that the bile acid receptor TGR5 is ubiquitously distributed in the canine gastrointestinal tract.

Blackleg in cattle: A case report of fetal infection and a literature review

Clostridium chauvoei causes blackleg in cattle. The disease has been reported worldwide, and although it can be prevented by vaccination, sporadic cases and occasional outbreaks still occur. We describe a case of blackleg in a 2-y-old, pregnant Gyr cow with in utero transmission to the fetus. The cow had characteristic gross and microscopic lesions of blackleg including widespread necrohemorrhagic and emphysematous skeletal and myocardial myositis, and fibrinous pericarditis. Her uterus contained a near-term, markedly emphysematous fetus with skeletal muscle and myocardial lesions similar to those seen in the dam. Histopathology of dam and fetal tissues revealed numerous gram-positive bacilli, many of them with sub-terminal spores, in multiple tissues. These bacilli were identified as C. chauvoei by immunohistochemistry. Anaerobic culture and fluorescent antibody tests performed on skeletal muscle from both the dam and fetus were positive for C. chauvoei, confirming a diagnosis of blackleg. Blackleg is a so-called endogenous infection, and the currently accepted pathogenesis involves ingestion of spores that are transported to muscle tissues where they lie dormant until anaerobiosis prompts germination. Germinating bacteria are histotoxic, producing severe, local necrosis and ultimately lethal toxemia. This model, however, has not been confirmed experimentally and also fails to explain some cases of the disease. A presumptive diagnosis of blackleg is based on clinical, gross, and histologic findings. Diagnostic confirmation necessitates the detection of C. chauvoei by culture, PCR, or immunodetection methods.

Are anti-ganglioside antibodies associated with proventricular dilatation disease in birds?

The identification of Parrot bornaviruses (PaBV) in psittacine birds with proventricular dilatation disease (PDD) has not been sufficient to explain the pathogenesis of this fatal disease, since not all infected birds develop clinical signs. Although the most accepted theory indicates that PaBV directly triggers an inflammatory response in this disease, another hypothesis suggests the disease is triggered by autoantibodies targeting neuronal gangliosides, and PDD might therefore resemble Guillain-Barré Syndrome (GBS) in its pathogenesis. Experimental inoculation of pure gangliosides and brain-derived ganglioside extracts were used in two different immunization studies. The first study was performed on 17 healthy chickens (Gallus gallus domesticus): 11 chickens were inoculated with a brain ganglioside extract in Freund’s complete adjuvant (FCA) and six chickens inoculated with phosphate-buffered saline. A second study was performed five healthy quaker parrots (Myiopsitta monachus) that were divided into three groups: Two quaker parrots received purified gangliosides in FCA, two received a crude brain extract in FCA, and one control quaker parrot received FCA alone. One chicken developed difficult in walking. Histologically, only a mild perivascular and perineural lymphocytic infiltrate in the proventriculus. Two quaker parrots (one from each treatment group) had mild lymphoplasmacytic encephalitis and myelitis. However, none of the quaker parrots developed myenteric ganglioneuritis, suggesting that autoantibodies against gangliosides in birds are not associated with a condition resembling PDD.

Chagas disease in a Texan horse with neurologic deficits

A 10-year-old Quarter Horse gelding presented to the Texas A&M University Veterinary Teaching Hospital with a six month-history of ataxia and lameness in the hind limbs. The horse was treated presumptively for equine protozoal myeloencephalitis (EPM) based on clinical signs but was ultimately euthanized after its condition worsened. Gross lesions were limited to a small area of reddening in the gray matter of the thoracic spinal cord. Histologically, trypanosome amastigotes morphologically similar to Trypanosoma cruzi, the agent of Chagas disease in humans and dogs, were sporadically detected within segments of the thoracic spinal cord surrounded by mild lymphoplasmacytic inflammation. Ancillary testing for Sarcocystis neurona, Neospora spp., Toxoplasma gondii and Leishmania spp. was negative. Conventional and real time polymerase chain reaction (PCR) of affected paraffin embedded spinal cord were positive for T. cruzi, and sequencing of the amplified T. cruzi satellite DNA PCR fragment from the horse was homologous with various clones of T. cruzi in GenBank. While canine Chagas disease cases have been widely reported in southern Texas, this is the first report of clinical T. cruzi infection in an equid with demonstrable amastigotes in the spinal cord. In contrast to previous instances of Chagas disease in the central nervous system (CNS) of dogs and humans, no inflammation or T. cruzi amastigotes were detected in the heart of the horse. Based on clinical signs, there is a potential for misdiagnosis of Chagas disease with other infectious diseases that affect the equine CNS. T. cruzi should be considered as a differential diagnosis in horses with neurologic clinical signs and histologic evidence of meningomyelitis that originate in areas where Chagas disease is present. The prevalence of T. cruzi in horses and the role of equids in the parasite life cycle require further study.

Characterization of a new genotype of avian bornavirus from wild ducks

Background

Avian bornaviruses (ABV) are a recently described group of intranuclear negative-stranded RNA viruses (Order Mononegavirales, Family Bornaviridae). At least 13 different ABV genotypes have been described. One genotype, the Canada goose genotype (ABV-CG), has been isolated from geese and swans and is widely distributed across North America.

Results

We have isolated and characterized a previously undescribed genotype of avian bornavirus from the brains of wild ducks. This new genotype, provisionally designated ABV genotype MALL, was detected in 12 of 83 mallards, and 1 of 8 wood ducks collected at a single location in central Oklahoma. The virus was cultured on primary duck embryo fibroblasts, fragments were cloned, and its genome sequence of 8904 nucleotides determined. This new genotype has 72% nucleotide identity and 83% amino acid identity with the ABV-CG genotype previously shown to be present in geese and swans. Histologic and immunohistochemical examination of the brains and eyes of four positive ducks indicated the presence of virus-infected neurons and glia in their cerebrums and retinas in the absence of inflammation.

Conclusions

More than one genotype of ABV is circulating in North American waterfowl. While the infected ducks were not observed to be suffering from overt disease, based on the immunohistochemistry, we speculate that they may have suffered some visual impairment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-014-0197-9) contains supplementary material, which is available to authorized users.

Nem tudo que parece ser, é lesão: aspectos anatômicos, não lesões, artefatos, lesões sem significado clínico e alterações post mortem encontrados na necropsia de suínos domésticos e selvagens (Sus scrofa)

A interpretação das alterações encontradas na necropsia é uma etapa importante para o sucesso do diagnóstico final. Este trabalho tem como objetivo descrever e ilustrar os aspectos anatômicos, não lesões, artefatos, lesões sem significado clínico e alterações post mortem encontradas em suínos domésticos e selvagens. Além disso, também se recomenda técnicas de colheita de tecidos para o diagnóstico de doenças que acometem essa espécie. Os principais aspectos anatômicos e não lesões descritos são fímbrias linguais, quadrilátero esofágico, toro pilórico e demarcação do padrão lobular do fígado (sistema gastrintestinal); tonsilas do palato mole, tecido linfoide associado ao estômago, placas de Peyer do intestino delgado e dobras da margem do baço (sistema hematopoiético); mediastino proeminente do testículo e aréolas da placenta (sistema reprodutor); atelectasia pulmonar e apêndice decidual (feto); e glândulas carpais (sistema tegumentar). Os artefatos de eutanásia abordados são petéquias na superfície do pulmão e rim, falsa anemia por sangria, hemorragia subdural por concussão cerebral, pseudo-infartos do baço e aspecto cerebriforme do intestino delgado. As lesões de pouco significado clínico descritas são cistos renais, linfonodos com pigmento de ferro, papilomas e hemangiomas no escroto, ossos no mesentério e hiperemia da mucosa gástrica. As alterações post mortem comumente encontradas são livor mortis, músculos pálidos, pseudomelanose e líquido serosanguinolento nas cavidades torácica e abdominal em fetos.

MRI findings in a rottweiler with leukoencephalomyelopathy

A 22 mo old male rottweiler presented with a 1 mo progressive history of general proprioceptive ataxia and upper motor neuron tetraparesis. Neurologic examination was consistent with a lesion affecting the first through fifth cervical spinal cord segments. MRI disclosed bilaterally symmetric hyperintensities on T2-weighted (T2W) images in the crus cerebri and pyramidal tracts of the brain and the dorsal portion of the lateral funiculi of the cervical spinal cord. Fifty days after initial presentation, the dog was euthanized due to disease progression. Pathologic examination of the central nervous system (CNS) revealed a bilaterally symmetric chronic leukoencephalomyelopathy (LEM) consistent with previous reports of LEM in rottweilers. To the authors' knowledge, this is the first report to describe the MRI characteristics of LEM in the rottweiler. The topography of the changes observed with MRI paralleled the pathologic changes, which were widespread loss of myelin, decreased axon numbers, and astroglial proliferation. Consequently, MRI of the CNS of affected rottweilers may aid in establishing a presumptive antemortem diagnosis of LEM.

Orientações para o diagnóstico de influenza em suínos

Este trabalho descreve a colheita adequada de amostras, as técnicas/procedimentos disponíveis para o diagnóstico de influenza A em suínos, assim como os resultados e suas respectivas interpretações, para auxiliar médicos veterinários de campo na identificação dessa doença. Em suínos vivos, as amostras adequadas são: secreção nasal, fluido oral e sangue (soro). Para suínos mortos, colher preferencialmente amostras de pulmão com consolidação cranioventral. Secreção nasal e fragmentos de pulmão refrigerado são utilizados para detectar partícula viral viável (isolamento viral - IV) ou ácido nucleico viral (RT-PCR convencional e RT-PCR em tempo real). As amostras não devem ser congeladas, pois o vírus é inativado a -20°C. A caracterização molecular dos isolados é feita pela análise filogenética obtida pelo sequenciamento de DNA. O soro é utilizado para a detecção de anticorpos (Acs) por meio do teste da inibição da hemaglutinação e ELISA. O fluido oral pode ser utilizado para detecção de anticorpo (ELISA) ou de vírus. Fragmentos de pulmão fixados em formol a 10% são examinados microscopicamente para identificar pneumonia broncointersticial e para detecção de antígeno viral pela imuno-histoquímica (IHQ). Para o sucesso do diagnóstico, as amostras devem ser colhidas de suínos que estão preferencialmente na fase aguda da doença, para aumentar as chances de detecção viral. As melhores opções para o diagnóstico de influenza A em suínos vivos são RT-PCR e isolamento viral de amostras de swab nasal ou fluido oral. Pulmão para análise por RT-PCR, isolamento viral ou IHQ é a amostra de escolha em suínos mortos. Testes sorológicos têm valor diagnóstico limitado e são utilizados apenas para determinar o estado imune do rebanho, não indicando doença clínica, pois os Acs são detectados 7-10 dias pós-infecção (fase subaguda). O diagnóstico de influenza é importante para avaliar o envolvimento desse agente no complexo de doença respiratória suína. Além disso, o isolamento do vírus influenza é essencial para o monitoramento dos principais subtipos circulantes em uma determinada região ou país, assim como para a detecção de novos rearranjos virais, já que influenza é considerada uma zoonose.

Immunohistochemical study of rabies virus within the central nervous system of domestic and wildlife species

Immunohistochemistry using a commercial polyclonal antibody for lyssavirus was applied to 39 archival cases of rabies. Paraffin blocks from 13 different species were available, including 3 dogs, 4 cats, 1 pig, 6 cattle, 4 horses, 1 llama, 7 skunks (Mephitis mephitis), 7 raccoons (Procyon lotor), 1 bat (Myotis species), 1 white-tailed deer (Odocoileus virginianus), 1 bobcat (Lynx rufus), 2 gray foxes (Urocyon cinereoargenteus), and 1 red fox (Vulpes vulpes). All cases had previously been diagnosed as rabies using histopathology and/or fluorescent antibody testing. The immunohistochemistry technique successfully detected lyssavirus antigen in all cases. In species for which 3 or more samples were available, distributional trends were seen in 4 main brain regions: brainstem, cerebellum, hippocampus, and cerebrum. The best site for rabies virus detection in dogs and cats was the hippocampus. For cattle, viral antigen was most prominent in the brainstem, followed by the cerebellum. In horses, the cervical spinal cord and adjacent brainstem were the optimal sites for detecting rabies virus antigen. In raccoons and skunks, positive labeling was widely dispersed, so selection might be less important for these wildlife reservoir species. Immunohistochemistry should prove useful in enhancing the accuracy of rabies diagnosis through informed selection of brain sampling sites when composite sampling is not feasible. This immunohistochemical technique could provide reliable virus detection in formalin-fixed tissues in any potentially infected species.

Achados de necropsia relacionados com a morte de 335 eqüinos: 1968-2007

Os protocolos de necropsia de 335 eqüinos necropsiados no LPV-UFSM entre 1968-2007 foram revisados com o objetivo de determinar os achados de necropsia relacionados com a causa da morte ou razão de eutanásia. A distribuição desses achados de acordo com os sistemas afetados foi a seguinte: digestivo (79/335 [23,6%]), músculo-esquelético (47/335 ([14,0%]), nervoso (37/335 [11,0%]), respiratório (35/335 [10,4%]), tegumentar (31/335 [9,3%]), hematopoético (24/335 [7,2%]), cardiovascular (13/335 [3,9%]), reprodutor (12/335 [3,5%]), urinário (7/335 [2,1%]) e endócrino (3/335 [0,9%]). Não foi possível determinar a causa da morte em 47 (14,0%) eqüinos necropsiados. As principais afecções do sistema digestivo foram as alterações na posição dos intestinos (17/79 [21,5%]), seguidas pelas obstruções e impactações (14/79 [17,7%]). As torções foram as principais alterações da posição dos intestinos (14/17 [82,4%]). Dentre as torções, as mais prevalentes foram as localizadas no intestino delgado (7/14 [50%]). A maioria dos eqüinos que morreram em razão de fratura óssea tinham idades entre 1-5 anos. As duas doenças mais freqüentemente diagnosticadas no sistema nervoso foram leucoencefalomalacia e tripanossomíase. Depressão respiratória causada por anestesia foi a principal causa de morte relacionada com o sistema respiratório. A anemia infecciosa eqüina foi a doença infecciosa mais diagnosticada e a principal razão para eutanásia observada neste estudo.

Intoxicações por plantas e micotoxinas associadas a plantas em bovinos no Rio Grande do Sul: 461 casos

Foi realizado um levantamento nos arquivos do Laboratório de Patologia Veterinária (LPV) da Universidade Federal de Santa Maria (UFSM) e revisados os laudos de necropsias de bovinos realizadas entre 1990 e 2005. Foram revisados 2.912 casos referentes a necropsias realizadas por membros do LPV ou a materiais de necropsias realizadas por veterinários de campo que enviaram amostras para avaliação histológica no LPV. Em 461 (15,83%) das necropsias, a causa da morte foi atribuída à ingestão de plantas tóxicas. Em ordem decrescente de freqüência, intoxicações pelas seguintes plantas foram diagnosticadas: Senecio spp (56,14%), Pteridium aquilinum (12,06%), Ateleia glazioviana (10,31%), Solanum fastigiatum (5,04%), Baccharis coridifolia (3,29%), Xanthium cavanillesii (3,07%), Senna occidentalis (2,63%), Ramaria flavo-brunnescens (2,41%), Amaranthus spp (2,19%), Vicia villosa (1,54%), Ipomoea batatas, Prunus sellowii e polpa cítrica (0,44% cada), Cestrum parqui, Claviceps paspali, Claviceps purpurea, Brachiaria spp e Lantana sp (0.22% cada). Em um determinado surto o número de bovinos afetados era substancialmente maior que o número de necropsias realizadas. São discutidos os aspectos relacionados à distribuição geográfica, fatores que induziram a ingestão, índices de morbidade, mortalidade e letalidade, sinais clínicos, achados de necropsia e histopatológicos para cada intoxicação. Quando conhecidos, foram incluídos na discussão aspectos relacionados ao princípio ativo e a patogenia da intoxicação.

Meningoencefalite por herpesvírus bovino-5

A meningoencefalite por herpesvírus bovino-5 (BoHV-5) é uma doença infecto-contagiosa, aguda ou subaguda, geralmente fatal e que afeta principalmente bovinos jovens submetidos a situações de estresse. A doença tem sido freqüentemente diagnosticada em várias regiões do Brasil e em outras partes do mundo. BoHV-5 é um vírus da família Herpesviridae e subfamília Alphaherpesvirinae e possui como genoma uma molécula de DNA fita dupla. Esses vírus são caracterizados por rápida replicação em cultivo, que resulta em lise das células infectadas, e afetam várias espécies de hospedeiros, estabelecendo latência principalmente em neurônios de gânglios sensoriais. A transmissão de BoHV-5 ocorre principalmente por contato direto ou indireto entre bovinos. Após a replicação primária nas mucosas oral, nasal, ocular e orofaríngea, o vírus invade as terminações nervosas e é transportado até os neurônios de gânglios sensoriais, onde replica ativamente e estabelece latência. A invasão viral do encéfalo pode resultar em replicação viral massiva e produção de doença neurológica. A maioria dos bovinos que desenvolvem doença neurológica morre em decorrência de meningo-encefalite, porém alguns podem desenvolver infecção subclínica e, após recuperação, permanecerem portadores da infecção latente. A disseminação viral nos rebanhos é facilitada em situações de grande concentração de animais, introdução de bovinos e desmame de lotes de bezerros em idade que coincide com o decréscimo da imunidade passiva. Certas condições, naturais ou induzidas, podem reativar o vírus do estado latente e propiciar condições para sua transmissão e disseminação a outros indivíduos. A doença pode ocorrer na forma de surtos ou em casos isolados, com coeficientes de morbidade que podem variar de 0,05%-5%; a letalidade é quase sempre de 100%. Os sinais clínicos incluem depressão, descarga nasal e ocular, ranger de dentes, andar em círculos, cegueira, febre, movimentos de pedalagem, disfagia, dor abdominal, nistagmo, tremores, sialorréia, incoordenação, opistótono, pressão da cabeça contra objetos, quedas e convulsões. A evolução do quadro clínico pode variar de 1 a 15 dias. Achados de necropsia podem estar ausentes, mas normalmente se observa tumefação das porções rostrais do córtex telencefálico e achatamento das circunvoluções, com segmentos amarelados e amolecidos (malacia). Com a evolução da doença, essas áreas se tornam gelatinosas e acinzentadas, e em casos avançados ocorre o desaparecimento segmentar do córtex telencefálico frontal (lesão residual). Em muitos casos podem ser observados focos de malacia na substância cinzenta dos núcleos basais e do tálamo. Histologicamente observa-se meningoencefalite não-supurativa necrosante, principalmente no córtex telencefálico frontal, associada a inclusões intranucleares eosinofílicas em astrócitos e neurônios, embora a freqüência dessas inclusões seja irregular. O diagnóstico de meningoencefalite por BoHV-5 deve ser feito com base nos achados epidemiológicos, clínicos, de necropsia e histopatológicos, associados com o isolamento do vírus em cultivo celular células ou com detecção de antígenos virais em seções do encéfalo ou em células descamadas presentes nas secreções nasais. A identificação e caracterização de BoHV-5 pode ser realizada por meio de testes com anticorpos mono-clonais, reação em cadeia de polimerase (PCR) e por análise de restrição genômica. Não há tratamento específico para a meningoencefalite por BoHV-5. Como o BoHV-1 e o BoHV-5 são antigenicamente muito semelhantes, recomenda-se a vacinação com vacinas para BoHV-1 como forma de reduzir as perdas causadas por BoHV-5, principalmente durante surtos de doença neurológica. Adicionalmente, outras medidas podem ser adotadas para prevenir ou reduzir os prejuízos ocasionados pela enfermidade, como testar sorologicamente os bovinos a serem introduzidos nos rebanhos, minimizar situações de estresse, sobretudo no desmame, e isolamento dos bovinos afetados.

Biópsia hepática no diagnóstico da intoxicação por Senecio brasiliensis (Asteraceae) em bovinos

Lesões hepáticas causadas pela intoxicação por Senecio spp em bovinos são progressivas e mortes podem ocorrer vários meses após a ingestão da planta. Testes laboratoriais da função hepática nem sempre são indicadores confiáveis de animais subclinicamente afetados. A biópsia hepática pode ser indicada para identificar bovinos com lesões hepáticas, mas sem sinais clínicos, e pode ter também valor prognóstico, uma vez que se acredita que as lesões hepáticas evoluam para causar insuficiência hepática e morte. Tais bovinos poderiam ser identificados pela biópsia hepática e enviados para o abate antes de desenvolverem os sinais clínicos, minimizando assim os prejuízos. Este estudo visou avaliar a biópsia hepática como um método de diagnóstico e prognóstico em casos de intoxi-cação por Senecio spp. em bovinos. Um surto de intoxicação por Senecio brasiliensis foi diagnosticado em bezerros de leite que haviam ingerido feno contaminado por 5-10% dessa planta tóxica. Biópsia hepática com agulha de Menghini por abordagem transtorácica foi realizada em 135 bezerros que ingeriram feno contaminado. Os bezerros biopsiados foram acompanhados por um período de 26 meses após a biópsia. Dezessete bezerros biopsiados tinham lesões típicas da intoxicação por Senecio spp (bezerros positivos) e 118 tinham fígados histologicamente normais (bezerros negativos). As lesões hepáticas dos bovinos positivos incluíam fibrose, hepatomegalocitose e hiperplasia de ductos biliares. Quinze dos 17 bezerros positivos morreram com sinais clínicos típicos de intoxicação por Senecio spp. 17-149 dias após a biópsia; 13 desses foram necropsiados e apresentavam lesões macro e microscópicas típicas de intoxicação por Senecio spp. Dois bovinos positivos mantinham-se clinicamente normais ao final do período de observação pós-biópsia. O valor prognóstico (sensibilidae) do teste foi considerado alto, uma vez que 88,23% dos bezerros positivos morreram. A especificidade do teste foi considerada bastante alta (99.16%), uma vez que apenas um dos 118 bovinos negativos na biópsia hepática morreu durante o período de observação pós-biópsia. Em nenhum bovino foi observado qualquer efeito negativo relacionado à técnica da biópsia hepática.