Ehrlichia canis infection in the cerebrospinal fluid of a dog characterized by morulae within monocytes and neutrophils.

An 8-year-old neutered female English Pointer was referred to a veterinary referral center (southwest of England) with a 4-5-month history of fecal incontinence and no evidence of urinary incontinence. Blood and free-catch urine samples were collected and sent to an off-site laboratory. Further investigations were postponed until laboratory results were available. Blood results showed a mild leukopenia, mild nonregenerative anemia, moderate to marked thrombocytopenia, and a mild increase in ALT and ALP activities. The primary veterinarian and client did not proceed with any further investigations for thrombocytopenia. Three weeks after the initial presentation, there was considerable clinical deterioration and progression of neurologic signs. Thoracic radiographs and an abdominal ultrasonographic examination were unremarkable. Magnetic resonance imaging (MRI) of the brain and spinal cord revealed an intramedullary lesion at the level of the C7 vertebra, a cystic lesion in the forebrain, and a bilateral lesion in the thalamus. A lumbar cerebrospinal fluid (CSF) was collected. CSF analysis showed a robustly increased protein concentration and marked pleocytosis. The cytologic evaluation revealed a mixed cellular population. Occasional neutrophils and monocytoid cells showed purple spherical intracellular inclusions, resembling Ehrlichia morulae. An aliquot of CSF was used off-label with a dot ELISA test, which showed a strong positive result for antibodies against Ehrlichia canis/Ehrlichia ewingii. PCR identified these morulae to be E canis. To best of the authors' knowledge, this is the first case of ehrlichial infection in canine CSF where Ehrlichia sub-species morulae present within neutrophils were confirmed to be Ehrlichia canis using PCR.

Investigation of human haemotropic Mycoplasma infections using a novel generic haemoplasma qPCR assay on blood samples and blood smears.

The aim of this study was to develop quantitative real-time (q)PCR assays to detect all known haemoplasma species, and a human housekeeping gene in order to demonstrate both successful DNA extraction from clinical samples and to test for sample inhibition, and to apply these qPCRs to human blood samples and blood smears. Sensitive and specific generic haemoplasma qPCR assays were developed to amplify haemoplasma species, as well as human glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an internal amplification control. An optimized technique for extracting DNA from stained blood smears was also developed. These methods were applied to anonymized blood samples obtained from 100 human immunodeficiency virus (HIV)-infected South Africans and 920 UK patients undergoing haematological examination, and to 15 blood smears recruited from previous studies describing human haemoplasmosis. Human GAPDH levels were acceptable in all but three of the blood samples and all but two of the blood smears. The latter could have arisen due to DNA degradation due to the old age (over 35 years) of these smears. Haemoplasma infection was found in one HIV-infected South African, but the species could not be characterized due to the very low levels of DNA present. This report describes novel extraction and qPCR methodologies for haemoplasma screening. Previously reported human haemoplasmosis based on cytological diagnosis alone should be viewed with caution.

Prevalence of hemotropic mycoplasmas in healthy and unhealthy cats and dogs in Spain.

The aims of the present study were to determine the prevalence of hemoplasmas in cats and dogs from the Barcelona area of Spain with the use of species-specific quantitative polymerase chain reaction (qPCR) assays and to evaluate any associations between hemoplasma infection, clinical presentation, and vector-borne infections. Blood samples from cats (191) and dogs (182) were included and were classified as healthy (149) or unhealthy (224). Ethylenediamine tetra-acetic acid blood samples underwent DNA extraction and qPCR analysis. Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum', and 'Candidatus Mycoplasma turicensis' were detected in cats, whereas Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum' were detected in dogs, with prevalences of 3.7%, 9.9%, 0.5%, 14.3%, and 0.6%, respectively. In cats, no association between hemoplasma infection and health status, age, breed, presence of anemia, Feline leukemia virus status, and other vector-borne infections was found, but outdoor access (P = 0.009), male sex (P = 0.01), and Feline immunodeficiency virus status (P < 0.001) were significantly associated with hemoplasma infection. In dogs, sex, age, health status, presence of anemia, and breed were not significantly associated with hemoplasma infection, but a significant association was found between hemoplasma infection and vector-borne infections (P < 0.001). The present report documents the occurrence of feline 'Candidatus M. turicensis' and canine 'Candidatus M. haematoparvum' infections in Spain.

Whole blood and tissue fungal DNA quantification in the diagnosis of canine sino-nasal aspergillosis.

Various combinations of tests are used to confirm the diagnosis of canine sino-nasal aspergillosis (SNA) because false-positive and false-negative results can occur with each test. Therefore, the aim of this study was to evaluate whether detection of fungal DNA in blood and nasal tissue samples was of value in the clinical diagnosis of this disease. Four groups were included in the study (dogs with SNA, lymphoplasmacytic rhinitis or nasal neoplasia, and control animals). Real-time PCR assays detecting DNA from all Penicillium and Aspergillus species (PenAsp assay) or species-specific DNA from A. fumigatus, A. terreus, A. flavus and A. niger were applied to whole blood and nasal tissue samples. Results obtained by PCR were compared between the groups. Sensitivity, specificity, positive and negative predictive values (PPV and NPV) for fungal DNA detection were compared with those for alternative diagnostic procedures including histopathology, serology and fungal culture. Significantly more fungal DNA was detected by the PenAsp assay in tissue biopsies from dogs with SNA than in the three other groups. Sensitivity, specificity, PPV and NPV for this method were 1.00, 0.06, 0.32 and 1.00. A. fumigatus DNA was detected in seven tissue biopsies from dogs with SNA and in one biopsy from a dog with a nasal tumour. Sensitivity, specificity, PPV and NPV for this diagnostic test were 0.50, 0.97, 0.87 and 0.82. No significant difference was found between the groups with respect to the amount of DNA detected in blood by the PenAsp assay. Sensitivity, specificity, PPV and NPV for this method were 0.71, 0.24, 0.31 and 0.64. A. fumigatus DNA was detected in the blood of three dogs with SNA and sixteen dogs without SNA. Sensitivity, specificity, PPV and NPV for this diagnostic tool were 0.21, 0.45, 0.15 and 0.54. Detection of A. fumigatus DNA in nasal tissue had the highest specificity, PPV and NPV but sensitivity of this method was low. Detection of fungal DNA in whole blood was of no value in the diagnosis of SNA.

Immunopathogenic pathways in canine inflammatory myopathies resemble human myositis.

Progress in the treatment of inflammatory myopathies is impeded by the lack of suitable animal models. Inflammatory myopathies occur spontaneously in the dog, are a heterogeneous group of disorders, and are more common than in humans. Clinical signs of weakness and muscle atrophy are reliably present, and there are histological and immunohistological similarities to forms of human myositis. In this study, microarray technology followed by quantitative real-time PCR and immunohistochemistry on muscle biopsy sections was used to investigate gene expression in cases of canine inflammatory myopathies. Several genes involved with innate and adaptive immunity were highly upregulated including those that participate in macrophage and dendritic cell activation and migration, and antigen processing and presentation. Other genes including those that participate in B cell growth, development, migration and activation, immunoglobulin genes, genes in pro-inflammatory and anti-inflammatory pathways, and genes involved with tissue remodeling were upregulated. In previous reports utilizing microarray technology in human myositis, there was activation of similar pathways involved in the immune response. This study strengthens the argument that forms of canine myositis may be important animal models of human myositis and suggests useful biomarkers for therapeutic response using the dog in pre-clinical trials.

The IgA system: a comparison of structure and function in different species.

The predominant immunoglobulin isotype on most mucosal surfaces is secretory immunoglobulin A (SIgA), a polypeptide complex comprising two IgA monomers, the connecting J chain, and the secretory component. The molecular stability and strong anti-inflammatory properties make SIgA particularly well suited to provide protective immunity to the vulnerable mucosal surfaces by preventing invasion of inhaled and ingested pathogens. In contrast to SIgA, IgA in serum functions as an inflammatory antibody through interaction with FcalphaR on immune effector cells. Although IgA appears to share common features and protective functions in different species, significant variations exist within the IgA systems of different species. This review will give an overview of the basic concepts underlying mucosal IgA defence which will focus on the variations present among species in structure, antibody repertoire development, pIgR-mediated transport, colostral IgA content, hepatobiliary transport, and function with particular emphasis on the IgA system of the pig and dog. These interspecies variations emphasise the importance of elucidating and analysing the IgA system within the immune system of the species of interest rather than inferring roles from conclusions made in human and mouse studies.

Cytokine mRNA quantification in duodenal mucosa from dogs with chronic enteropathies by real-time reverse transcriptase polymerase chain reaction.

The pathogenesis of inflammatory bowel disease (IBD) and antibiotic-responsive diarrhea (ARD) in dogs likely involves an interaction between the intestinal immune system and luminal bacterial or food antigens. German Shepherd Dogs (GSD) are particularly predisposed to both IBD and ARD. CD4+ T cells are important for the regulation of immune responses in the mucosa, and they exert their effects through the secretion of cytokines. The present study examined the role of cytokines in the pathogenesis of canine chronic enteropathies by quantification of mRNA encoding interleukin-2 (IL-2), IL-4, IL-5, IL-6, IL-10, IL-12, IL-18, interferon gamma, tumor necrosis factor-alpha, transforming growth factor-beta, and glyceraldehyde-3-phosphate dehydrogenase by real-time reverse transcriptase polymerase chain reaction in duodenal mucosal biopsies obtained from 39 dogs with chronic diarrhea and 18 control dogs. Contemporaneously collected biopsies were assessed for histologic changes with a 4-point grading system. No significant difference in the expression of cytokine mRNA (P > .01) was detected between dogs with and those without chronic diarrhea. Similarly, no significant differences in cytokine mRNA expression were observed between GSD and other breeds with chronic diarrhea, or between histologically normal duodenal mucosa and that with evidence of inflammatory change. Failure to detect a difference in mRNA expression does not rule out the possibility of a defect downstream at the level of translation or protein function. No conclusion can be drawn from these data as to the predominant CD4+ cell type in the pathogenesis of these canine chronic enteropathies.

Measurement of messenger RNA encoding the alpha-chain, polymeric immunoglobulin receptor, and J-chain in duodenal mucosa from dogs with and without chronic diarrhea by use of quantitative real-time reverse transcription-polymerase chain reaction assays.

OBJECTIVE: To examine the difference in expression of messenger RNA (mRNA) transcripts for polymeric immunoglobulin receptor (plgR), alpha-chain, and J-chain determined by use of quantitative real-time reverse transcription-polymerase chain reaction (QRT-PCR) assays in duodenal biopsy specimens obtained from dogs with and without chronic diarrhea. SAMPLE POPULATION: Biopsy specimens of the proximal portion of the duodenum were obtained endoscopically from 39 dogs evaluated because of chronic diarrhea (12 German Shepherd Dogs and 27 non-German Shepherd Dog breeds); specimens were also obtained from a control group of 7 dogs evaluated because of other gastrointestinal tract diseases and 2 dogs that were euthanatized as a result of nongastrointestinal tract disease. PROCEDURE: Dogs were anesthetized, and multiple mucosal biopsy specimens were obtained endoscopically at the level of the caudal duodenal flexure by use of biopsy forceps; in 2 control dogs, samples were obtained from the descending duodenum within 5 minutes of euthanasia. One-step QRT-PCR was used to quantify the level of expression of transcripts for the housekeeper gene glyceraldehyde-3-phosphate dehydrogenase, plgR, alpha-chain, and J-chain in duodenal mucosal tissue. RESULTS: There was no significant difference in the level of expression of any transcript among non-German Shepherd Dog breeds without diarrhea (control group), non-German Shepherd Dog breeds with chronic diarrhea, and German Shepherd Dogs with chronic diarrhea. Conclusions and Clinical Relevance-Results indicated that the susceptibility of German Shepherd Dogs to chronic diarrhea is not a result of simple failure of transcription of the key genes that encode molecules involved in mucosal IgA secretion.

Quantitative real-time RT-PCR measurement of mRNA encoding alpha-chain, pIgR and J-chain from canine duodenal mucosa.

IgA is the predominant immunoglobulin class in mucosal secretions and secretory deficiencies may predispose to chronic enteropathies. The polymeric immunoglobulin receptor (pIgR) facilitates the transport of IgA across the epithelial border. Critical to the transport of IgA by pIgR is the presence of a polypeptide joining chain (J-chain) linking the IgA monomers of the dimeric IgA molecule. In this study we examine the difference in expression of mRNA transcripts for pIgR, alpha-chain and J-chain by real-time reverse-transcription polymerase chain reaction (RT-PCR) in endoscopic biopsies from the duodenum of dogs with and without chronic diarrhoea. One-step, real-time RT-PCR was used to quantify the level of expression of transcripts for the housekeeper gene G3PDH, pIgR, alpha-chain and J-chain. There was no significant difference in expression of any transcript between dogs with (n=11) and without (n=8) chronic diarrhoea. Expression of alpha-chain mRNA in both groups had a similar bimodal distribution, as individuals either expressed relatively 'high' or 'low' levels of this transcript. The secretion of IgA by plasma cells is under the control of Th-2 cytokines, therefore the finding of 'high' and 'low' levels of alpha-chain expression may reflect different levels of these cytokines in duodenal mucosa.