Borna disease in an adult free-ranging Eurasian beaver (Castor fiber albicus).

Borna disease (BD) associated with a peracute bacterial septicaemia with Escherichia coli was diagnosed in an adult female, naturally infected, free-ranging Eurasian beaver of the subspecies Castor fiber albicus, clinically characterized by weight loss, depression, weakness and gurgled peristaltic sounds. The beaver was euthanized humanely. Necropsy and light microscopy revealed a non-purulent meningoencephalitis with typical mononuclear perivascular cuffs and parenchymal infiltrates. The diagnosis of BD was confirmed by detection of viral antigen and RNA by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The PCR product was sequenced and cluster analysis revealed a close relationship between endemic clusters in Saxony-Anhalt. This is the first report of naturally occurring BD in a free-ranging Eurasian beaver.

C-reactive protein concentration has limited value in the diagnosis of meningoencephalitis of unknown origin in dogs.

OBJECTIVES: To evaluate blood and cerebrospinal fluid (CSF) concentrations of C-reactive protein (CRP) in dogs with meningoencephalitis of unknown origin (MUO); to evaluate whether blood CRP concentration is associated with epidemiological, clinicopathologic, and MRI findings; and to investigate blood CRP predictive power in survival. ANIMALS: 30 client-owned dogs with MUO, 15 client-owned dogs with steroid-responsive meningitis arteritis (SRMA; positive control group), and 15 healthy dogs (negative control group). METHODS: Blood CRP concentration was measured in each group, while it was performed in CSF only in the MUO and SRMA groups. The analysis of epidemiological data included breed, age, sex, duration of clinical signs, and history of seizures. Blinded analysis of MRI was performed based on a classification grid, and traditional CSF analysis parameters were assessed. The predictive power of blood CRP concentration regarding survival at 6 months was investigated. RESULTS: Of the 30 dogs with MUO, 9 (30%) had an increased CRP concentration in blood, and 3 (10%) showed a measurable CRP in CSF. Median blood CRP concentration in dogs with MUO was 0.1 mg/L (range, 0.1 to 102 mg/L), which was not statistically different from the healthy dog group but significantly lower than the SRMA control group. Only the duration of clinical signs was positively associated with an increased blood CRP level. Blood CRP concentration was not associated with survival at 6 months. CLINICAL RELEVANCE: Blood CRP concentration is of limited value for the diagnosis and prognosis of dogs with MUO. Chronicity of the disease may be associated with an increased concentration of blood CRP.

An early clinical phenotype of necrotizing meningoencephalitis in the Pug reveals similarities to multiple sclerosis in humans.

Necrotizing meningoencephalitis (NME) is a fatal neuroinflammatory disease that previously carried a uniformly grave prognosis. Our recent identification of a novel early form of NME in Pugs suggests that disease onset and progression are likely more insidious than previously recognized and provides new hope that early therapeutic intervention may halt disease progression and ultimately prevent or cure NME. This novel perspective also sheds new light on the clinical similarities to multiple sclerosis (MS) in humans and provides a rationale for cross-species translation. The history of recent scientific discoveries in NME and new parallels between MS and NME will be reviewed.

Retrospective evaluation of prognosis and survival with various immunosuppressants in 82 dogs diagnosed with meningoencephalitis of unknown etiology (2010-2021).

BACKGROUND: Meningoencephalomyelitis of unknown etiology (MUE) is a comprehensive term for non-infectious inflammatory brain diseases of the central nervous system (CNS) caused by abnormal autoimmune responses. This study aims to compare the differences in survival and clinical response of MUE according to the adjuvant immunosuppressant use. Medical records of 82 dogs diagnosed with MUE were reviewed retrospectively. RESULTS: The overall survival time was 769 days (range 14-2687 days). The median survival time for each adjunctive was: leflunomide 1035 days (range 126-2163 days), mycophenolate mofetil 865 days (range 39-2191 days), cyclosporin 441 days (range 11-2176 days), cytosine arabinoside 754 days (range 6-1898 days) and a combination of mycophenolate mofetil and cytosine arabinoside 132 days (range 23-1227 days). There was no significant difference in the incidence rate of adverse events according to the immunosuppressants, but moderate to severe anemia was confirmed in 3 patients (18.7%) in the leflunomide group. CONCLUSIONS: The survival time and response rate of MUE dogs differed depending on which adjunctive immunosuppressants were used. Leflunomide showed a long survival time and a relatively good response rate in dogs with MUE. However, a large-scale further study with standardized doses of immunosuppressants and supportive treatment and constant monitoring interval is needed.

Investigation of side effects to treatment and cause of death in 63 Scandinavian dogs suffering from meningoencephalitis of unknown origin: a retrospective study.

BACKGROUND: Meningoencephalitis of unknown origin is a common cause of severe neurological disease in dogs. The term covers a heterogeneous group of noninfectious inflammatory diseases, with immune dysregulation widely accepted as the underlying disease mechanism. Current treatment consists of immunosuppression, with corticosteroids being the mainstay of virtually all treatment regimens. However, side effects of corticosteroids can be severe, and might be the cause of death in some patients. This retrospective, multi-centric study aimed at describing a population of Scandinavian dogs with meningoencephalitis of unknown origin in regards to reported side effects and cause of death, and to highlight possible differences in survival, when comparing corticosteroid monotherapy with other treatment regimens. RESULTS: Within the 5-year study period, 63 dogs were included. Of these, 35 (49.3%) died or were euthanized during the study period. Median survival time from time of diagnosis based on Kaplan-Meier curves for the overall population was 714 days (equivalent to around 25 months, range 0-1678 days). There was no statistically significant difference (P = 0.31) in survival between dogs treated with corticosteroid monotherapy (n = 26, median survival time 716 days, equivalent to around 25 months, range 5-911 days), dogs receiving a combination of corticosteroids and ciclosporin (n = 15, median survival time 916 days, equivalent to around 31 months, range 35-1678 days), and dogs receiving corticosteroids combined with either cytosine arabinoside, leflunomide, or a combination of 2 or more add-on drugs (n = 13, median survival time 1186 days, equivalent to around 40 months, range 121-1640 days). Side effects were registered for 47/63 dogs. Polyphagia (n = 37/47), polyuria/polydipsia (n = 37/47), diarrhea (n = 29/47) and lethargy (n = 28/47) were most frequently reported. The most common cause for euthanasia was relapse (n = 15/35, 42.9%), followed by insufficient or lack of treatment response (n = 9, 25.7%). Side effects were the direct cause of euthanasia in 2/35 dogs (5.7%). CONCLUSIONS: A large proportion of dogs in the overall population were euthanized due to relapse, emphasizing a need for treatment regimens aimed at specifically preventing relapse for an improved long-term survival. Side effects in dogs receiving corticosteroid monotherapy were rarely a direct cause of death, but were reported for all dogs. No statistically significant difference in survival was found when corticosteroid monotherapy was compared to other treatment regimens.

Application of metagenomics for diagnosis of broilers displaying neurological symptoms.

BACKGROUND: Thirty-two-day-old broiler chickens at a farm located in northwestern South Korea displayed adverse neurological symptoms including limping, lying down, and head shaking. Approximately 2.1% of chickens died or were culled due to severe symptoms. Five carcasses were submitted to the Avian Disease Division of the Animal and Plant Quarantine Agency (APQA) for disease diagnosis. RESULTS: Broilers displayed severe pericarditis and perihepatitis associated with gross lesions. Broilers also displayed microscopic lesions in the cerebrum and in the granular layer of the cerebellum, which were associated with multifocal perivascular cuffing and purulent necrosis in the cerebrum, and severe meningitis with heterophil and lymphocyte infiltration. Staphylococcus spp. were identified in the liver and heart using bacteriological culture. PCR/RT-PCR assays revealed that broilers were negative for avian Clostridium botulinum, Newcastle disease virus, and avian encephalomyelitis virus. Bacterial and viral metagenomic analysis of brain sample further revealed the presence of Pseudomonas spp. and Marek's disease virus, which are known etiological agents of chicken meningoencephalitis. CONCLUSIONS: This study reports a diagnostic analysis of gross and histopathological lesions from 32-day-old broilers displaying unique neurological symptoms that revealed the presence of the several neurological diseases including meningoencephalitis. The causative agents associated with meningoencephalitis of broilers that had not been identified by routine diagnostic methods could be diagnosed by metagenomics, which proves the usefulness of metagenomics as a diagnostic tool for unknown neurological diseases in broilers.

Shared and unique antibody and B cell profiles in HIV-positive and HIV-negative individuals with cryptococcal meningoencephalitis.

Host non-T cell markers to aid in the diagnosis of cryptococcal meningoencephalitis (CM) have not been identified. In this case-control study, we characterized antibody and B cell profiles in HIV-negative and HIV-positive Vietnamese individuals of the Kinh ethnicity recently diagnosed with CM and controls. The study included 60 HIV-negative with no known immunocompromising condition and 60 HIV-positive individuals, with 30 CM cases and 30 controls in each group. Participants were matched by age, sex, HIV serostatus, and CD4 count in the HIV-positive group. Plasma immunoglobulin (Ig) levels, including IgG1, IgG2, IgM, and IgA, Cryptococcus spp. glucuronoxylomannan (GXM)- and laminarin (branched ${\rm{\beta }}$-[1-3]-glucan)-binding IgG, IgM, IgA levels, and peripheral blood B cell subsets were measured. Logistic regression, principal component, and mediation analyses were conducted to assess associations between antibody, B cell levels, and CM. The results showed that GXM-IgG levels were higher and IgG1 and IgG2 were lower in CM cases than controls, regardless of HIV status. In HIV-negative individuals, IgG2 mediated an inverse association between CD19+CD27+CD43+CD5- (B-1b-like) cells and CM. In HIV-positive individuals, lower levels of IgA, laminarin-IgA, and CD19+CD27+IgM+IgD- (IgM+ memory B) cells were each associated with CM. The shared and distinct antibody and B cell profiles identified in HIV-negative and HIV-positive CM cases may inform the identification of non-T-cell markers of CM risk or unsuspected disease, particularly in HIV-negative individuals.

Unlike cryptococcal meningitis (CM) in HIV-positive individuals, there are no known biomarkers of risk in HIV-negative individuals and the diagnosis is often not suspected and delayed. This study identified non-T cells, including antibody and B cell CM-associated profiles that may guide cryptococcal antigen testing in HIV-negative individuals.

Immunohistochemical evaluation of fibrin/fibrinogen, d-dimers, and intravascular thrombosis in brains of dogs with meningoencephalitis of unknown origin.

Granulomatous meningoencephalitis (GME) and necrotizing encephalitides (NE) are the most common immune-mediated inflammatory diseases of the central nervous system in dogs. Activation of the fibrinolytic system in multiple sclerosis, a similar immune-mediated disease affecting the central nervous system in humans, seems to be related to disease progression. The aim of this study was to identify fibrin/fibrinogen and D-dimer deposition, as well as presence of intravascular thrombosis (IVT) in brains of dogs with a diagnosis of GME or NE. Immunohistochemical studies using antibodies against fibrin/fibrinogen and D-dimers were performed. Statistical analyses were performed to determine whether there were differences in the presence and location of fibrin/fibrinogen, D-dimers deposits, and IVT between GME and NE. Samples from sixty-four dogs were included in the study: 32 with a diagnosis of GME and 32 with a diagnosis of NE. Fibrin/fibrinogen depositions were detected in all samples and d-dimers were detected in 43/64 samples. IVT was present in 29/64 samples, with a significantly higher score in samples from dogs with NE than in samples from dogs with GME (P = 0.001). These data support hemostatic system activation in both diseases, especially NE. This finding might be related to the origin of the necrotic lesions seen in NE, which could represent chronic ischemic lesions. Further studies are needed to investigate the association between vascular lesions and the histopathological differences between GME and NE and the hemostatic system as a potential therapeutic target.

Meningoencephalomyelitis associated with foreign plant material in a dog: case report and brief literature review.

Neurologic disease associated with migration of plant material is reported infrequently in dogs. Here we describe meningoencephalomyelitis associated with foreign plant material in a 2-y-old castrated male West Highland White Terrier dog with acute neck pain. Magnetic resonance imaging revealed spinal meningeal contrast enhancement. Although clinical signs improved after treatment with steroids, the dog was readmitted for further evaluation 3-mo later and was euthanized after generalized epileptic seizures. Autopsy findings consisted of coalescing, pus-filled, neuroparenchymal cavitations surrounded by hemorrhage in the left caudal colliculus and rostral left cerebellar hemisphere. Histologically, lesions consisted of necrosis and suppuration, which surrounded a 1 × 2-mm foreign body morphologically consistent with plant material and clusters of gram-positive bacterial cocci. Affected areas were surrounded by reactive astrocytes, fibrous connective tissue, and mixed inflammatory infiltrates. Areas of hemorrhage and infiltration by neutrophils and foamy macrophages with fibrinoid change of small capillaries were observed in the adjacent neuroparenchyma. The inflammation extended to the perivascular spaces in the leptomeninges (mesencephalon, cerebellum, and brainstem, and spinal cord) and spinal central canal. Anaerobic bacterial culture of frozen samples of cerebellum yielded heavy growth of Bacteroides pyogenes.

Amdoparvovirus-associated disease in striped skunks (Mephitis mephitis).

Disease caused by the archetypical amdoparvovirus (APV), Aleutian mink disease virus (AMDV), has been well studied, but APV infections in other carnivores are poorly understood. Skunk amdoparvovirus (SKAV), one of a handful of newly discovered APVs, is apparently species-specific in striped skunks (Mephitis mephitis) and has a high prevalence across North America. We have evaluated the infection status and viral tissue distribution in a cohort of 26 free-ranging California skunks from a single rehabilitation facility who were euthanized due to poor prognosis for recovery from neurologic disease. SKAV was detected in the majority of this cohort, and virus was associated with a spectrum of lesions including tubulointerstitial nephritis, meningoencephalitis, myocarditis, and arteritis. Affected tissue and patterns of inflammation were partially overlapping with those of AMDV infection but were notably distinct in the kidney.

Association between neurofilament light chain concentration and lesion size in dogs with meningoencephalitis of unknown origin.

BACKGROUND: Neurofilament light chain (NfL) is an axonal cytoplasmic protein in neurons. Recently, NfL has shown potential as a diagnostic biomarker in dogs with meningoencephalitis of unknown origin (MUO). However, there have been no studies on the biomarkers of lesion progression and resolution in MUO. OBJECTIVES: To identify the potential of NfL as a biomarker for predicting changes in lesions. METHODS: Seven dogs with MUO who had undergone two magnetic resonance imaging (MRI) scans were included. The serum NfL levels were measured using a single-molecule array. The relationship between the rate of change in lesion size and the rate of change in serum NfL level was analysed using simple linear regression. To investigate the effect of changes in lesion size on NfL levels, the dogs were divided into two groups depending on the change in lesion size: decreased lesion size group (n = 5) and increased lesion size group (n = 2). Trends in lesion size change were identified in the second MRI compared with the first MRI. RESULTS: A significant positive relationship between the rate of lesion size change and the rate of NfL level change was identified (R2 = 0.9239, p = 0.0006). In the decreased lesion size group (n = 5), all NfL levels in each dog decreased, and in the increased lesion size group (n = 2), all NfL levels in each dog increased. CONCLUSIONS: This preliminary study showed a positive relationship between the rate of change in lesion size and rate of change in serum NfL levels. Therefore, the serum NfL level may be a promising biomarker of lesion progression and resolution in MUO.

Meningoencephalitis caused by concurrent infection with canine distemper virus and a unique Sarcocystis sp. in a gray fox.

A deceased 9-wk-old male gray fox (Urocyon cinereoargenteus) with a history of decreased ambulation and diarrhea was submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory. No significant gross findings were evident on postmortem examination. Histologically, the cerebrum and brainstem had mild necrotizing meningoencephalitis with protozoal schizonts and merozoites. Additionally, glial cells contained intracytoplasmic and intranuclear viral inclusion bodies. Sections of the cerebrum were positive for canine distemper virus (CDV) and negative for Sarcocystis neurona on immunohistochemistry. Bayesian analysis revealed that this Sarcocystis sp. clustered most closely with a clade of unnamed Sarcocystis sp. found in viperid snakes, with a posterior probability of 99%. CDV likely played a significant role in the expression of clinical sarcocystosis in this gray fox.

Abnormal Hyperphosphorylation of Tau in Canine Immune-mediated Meningoencephalitis.

BACKGROUND/AIM: Tau is a microtubule-associated protein involved in the assembly and stabilization of microtubules. In human medicine, hyperphosphorylation of tau is associated with microtubule instability and is considered to play a role in the progression of multiple sclerosis (MS). MS is an autoimmune neurological disease that shares many characteristics, including pathological mechanisms, with canine meningoencephalitis of unknown etiology (MUE). With this background, this study investigated the presence of hyperphosphorylated tau in dogs with MUE and experimental autoimmune encephalomyelitis (EAE). MATERIALS AND METHODS: In total, eight brain samples were examined from two neurologically normal dogs, three dogs with MUE, and three canine EAE models. Anti-(phospho-S396) tau antibody was used for immunohisto-chemistry, which stained hyperphosphorylated tau. RESULTS: In normal brain tissues, hyperphosphorylated tau was not found. In all the dogs with EAE and one of the dogs with MUE, immunoreactivity for S396 p-tau was observed in glial cell cytoplasm and the background in the periphery of the inflammatory lesion. CONCLUSION: These results suggest for the first time that tau pathology may be involved in the progression of neuroinflammation in dogs, similar to that in human MS.

Rustrela Virus as Putative Cause of Nonsuppurative Meningoencephalitis in Lions.

Retrospective investigation of archived tissue samples from 3 lions displaying nonsuppurative meningoencephalitis and vasculitis led to the detection of rustrela virus (RusV). We confirmed RusV antigen and RNA in cortical neurons, axons, astrocytes and Purkinje cells by reverse transcription quantitative PCR, immunohistochemistry, and in situ hybridization.

Rapport de cas Mononuclear pleocytosis and meningoencephalitis caused by Listeria monocytogenes in an adult horse.

Clinical disease caused by infection with Listeria monocytogenes is rare in adult horses, and there is a paucity of ante-mortem clinicopathologic changes for this species reported in the literature. Confirmatory diagnosis is difficult and often requires post-mortem sampling of the brainstem. This report details a case of meningoencephalitis caused by Listeria monocytogenes in an adult American quarter horse gelding presenting with central neurologic signs. Pre-mortem analysis of the cerebrospinal fluid revealed a mononuclear, primarily lymphocytic, pleocytosis, which is a reported finding in other species with listeriosis. Post-mortem histopathologic changes of the brainstem were characteristic of listeriosis, and infection was confirmed with immunohistochemical labeling and bacterial culture. Key clinical message: Listeriosis should be included as a differential diagnosis in neurologic horses with mononuclear pleocytosis identified on cerebrospinal fluid analysis.

Pléocytose mononucléaire et méningo-encéphalite causées par Listeria monocytogenes chez un cheval adulte. La maladie clinique causée par une infection à L. monocytogenes est rare chez les chevaux adultes, et il y a peu de changements clinico-pathologiques ante-mortem rapportés dans la littérature pour cette espèce. Le diagnostic de confirmation est difficile et nécessite souvent un prélèvement post-mortem du tronc cérébral. Ce rapport détaille un cas de méningo-encéphalite causée par L. monocytogenes chez un hongre quarter horse américain adulte présentant des signes neurologiques centraux. L'analyse pré-mortem du liquide céphalo-rachidien a révélé une pléocytose mononucléaire, principalement lymphocytaire, qui est une trouvaille rapportée chez d'autres espèces atteintes de listériose. Les modifications histopathologiques post-mortem du tronc cérébral étaient caractéristiques de la listériose et l'infection a été confirmée par un marquage immunohistochimique et une culture bactérienne.Message clinique clé :La listériose doit être incluse comme diagnostic différentiel chez les chevaux avec signes neurologiques présentant une pléocytose mononucléaire identifiée lors de l'analyse du liquide céphalo-rachidien.(Traduit par Dr Serge Messier).

Development of a reliable clinical assessment tool for meningoencephalitis in dogs: The neurodisability scale.

BACKGROUND: Meningoencephalitis of unknown origin (MUO) comprises a group of debilitating inflammatory diseases affecting the central nervous system of dogs. Currently, no validated clinical scale is available for the objective assessment of MUO severity. OBJECTIVES: Design a neurodisability scale (NDS) to grade clinical severity and determine its reliability and whether or not the score at presentation correlates with outcome. ANIMALS: One hundred dogs with MUO were included for retrospective review and 31 dogs were subsequently enrolled for prospective evaluation. METHODS: Medical records were retrospectively reviewed for 100 dogs diagnosed with MUO to identify the most frequent neurological examination findings. The NDS was designed based on these results and evaluated for prospective and retrospective use in a new population of MUO patients (n = 31) by different groups of independent blinded assessors, including calculation of interobserver agreement and association with outcome. RESULTS: The most common clinical signs in MUO patients were used to inform categories for scoring in the NDS: seizure activity, ambulatory status, posture and cerebral, cerebellar, brainstem, and visual functions. The intraclass correlation coefficient (ICC) for prospective use of the NDS was 0.83 (95% confidence interval [CI], 0.68-0.91) indicating good agreement, and moderate agreement was found between prospective and retrospective assessors (ICC, 0.71; 95% CI, 0.56-0.83). No association was found between NDS score and long-term outcome. CONCLUSIONS AND CLINICAL IMPORTANCE: The NDS is a novel clinical measure for objective assessment of neurological dysfunction and showed good reliability when used prospectively in MUO patients but, in this small population, no association with outcome could be identified.

Clinical presentation, treatment, and outcome of 24 dogs with bacterial meningitis or meningoencephalitis without empyema (2010-2020).

BACKGROUND: Bacterial meningitis (BM) and meningoencephalitis (BMEM) are associated with high case fatality rates and neurologic sequelae in people, but limited data exists on outcome in dogs. HYPOTHESIS/OBJECTIVES: To report the clinicopathologic features, treatment and outcome of BM/BMEM in dogs, with a focus on clinical presentation, relapse and long-term neurological deficits. ANIMALS: Twenty-four client-owned dogs diagnosed with BM/BMEM without empyema. METHODS: Retrospective case series of dogs diagnosed with BM/BMEM from 5 veterinary referral hospitals between January 2010 and August 2020. RESULTS: Twenty-four dogs were included. Median duration of clinical signs was 2 days (range ≤24 hours to 30 days) and signs recorded included pyrexia (3) and cervical hyperesthesia (10). Neurological deficits were present in 18 dogs including altered mentation (12), ataxia (8), nonambulatory status (8), head tilt (8), and cranial nerve deficits (13). Intracellular bacteria were visualized on cerebrospinal fluid (CSF) analysis in 15/24 dogs, with positive CSF bacteriological culture in 8/21. Otitis media/interna (OMI) was diagnosed in 15/24 dogs, of which 6/15 dogs underwent total ear canal ablation and lateral bulla osteotomy. Twenty dogs survived to hospital discharge. Median duration of antibiotic administrations was 8 weeks (range, 2-16 weeks). Glucocorticoids were administered to 15 dogs. Median follow-up time was 92 days (range, 10-2233 days). Residual neurological deficits were reported in 9 dogs, with a single case of suspected relapse. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinical signs were variable in dogs with BM/BMEM, the nidus of bacterial infection was often OMI and the majority of dogs made a full recovery with treatment.

Assessment of oligoclonal bands in cerebrospinal fluid and serum of dogs with meningoencephalitis of unknown origin.

BACKGROUND: Meningoencephalitis of unknown origin (MUO) is an inflammatory disease of the canine central nervous system (CNS) that shares several features with multiple sclerosis (MS) in humans. In approximately 95% of MS patients, ≥ two immunoglobulin G (IgG) oligoclonal bands (OCBs) are detectable exclusively in the cerebrospinal fluid (CSF). HYPOTHESIS/OBJECTIVES: To investigate OCBs in CSF and serum in dogs affected by MUO, intervertebral disc disease (IVDD), idiopathic epilepsy (IE), intracranial neoplasia (IN), steroid-responsive meningitis-arteritis (SRMA), and diseases outside the CNS. We hypothesize that the highest prevalence of CSF-specific OCBs (≥ two OCBs uniquely in the CSF) would be found in dogs affected by MUO. ANIMALS: Client-owned dogs (n = 121) presented to the neurology service due to neurological deficits. METHODS: Prospective study. Measurement of IgG concentration in CSF and serum via a canine IgG ELISA kit. OCB detection via isoelectric focusing (IEF) and immunoblot. RESULTS: Presence of CSF-specific OCBs was significantly higher in dogs with MUO (57%) compared to 22% in IN, 6% in IE, 15% in SRMA, 13% in IVDD, and 0% in the non-CNS group (p < .001). Dogs with MUO were 9.9 times more likely to show CSF-specific OCBs than all other diseases together (95% confidence interval, 3.7-26.4; p < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: MUO showed the highest prevalence of CSF-specific OCBs, indicating an inflammatory B cell response. Future studies are needed to evaluate the prevalence in the specific MUO subtypes and a possible similarity with human MS.

Persistent marked cerebrospinal fluid eosinophilia in a dog with primary central nervous system histiocytic sarcoma.

A 6-year-old female spayed Jack Russell Terrier was evaluated for episodic seizure-like activity and intermittent obtundation over the previous 3 weeks. Magnetic resonance imaging (MRI) of the brain revealed mild generalized dilation of the ventricular system with periventricular edema. A focal area of mildly increased lepto- and pachymeningeal contrast uptake in the region of the right parietal and occipital lobes was observed. Analysis of cerebrospinal fluid (CSF) revealed marked mixed pleocytosis with 20% eosinophils and no atypical cells or microorganisms. The dog transiently improved with prednisolone for suspected eosinophilic meningoencephalitis/meningoencephalomyelitis of unknown origin (MUO) but worsened over the following 5 months. Brain MRI and CSF sampling were repeated. Additional multifocal lesions were evident in the brainstem and cerebellum. On CSF analysis, the eosinophilic pleocytosis and increased total protein persisted. The clinical signs progressed despite treatment, and the patient was euthanized 6 weeks later. A post-mortem examination was performed. Histopathology and immunohistochemistry revealed a multifocal neoplastic proliferation of cells in the brain, diffusely and strongly positive for ionized calcium-binding adapter molecule (Iba-1) and negative for AE1/AE3 pan-cytokeratin and glial-fibrillar-acid-protein (GFAP) immunostaining, consistent with a diagnosis of histiocytic sarcoma (HS). No other organic lesions were found; therefore, the neoplasm was considered a primary HS of the central nervous system (CNS). This case report stresses the importance of considering primary CNS HS in the differential diagnosis of dogs with marked CSF eosinophilia, even in the absence of atypical cells on cytologic examination.

Phlebovirus detection on phlebotomine sandflies in Lampedusa Island (Italy).

Phleboviruses are common human pathogens diffused on the Mediterranean area whose infection can cause the typical prodromal symptom of a mild three­days fever. In particular, Toscana Virus (TOSV) has a great concern since its capacity to provoke central nervous system disorders like meningoencephalitis. Furthermore, as the phlebotomine arthropod vectors represent the main carrier for pathogens of the genus Leishmania as well, the purpose of the study was to investigate the presence of TOSV in Lampedusa, Italy previously reported for leishmaniosis infection cases. The survey was carried out through an initial sampling phase of sand flies, by means of CDC light traps, and a second step of molecular analyses. The genomic S­segment of TOSV was targeted. The positive samples were sequenced and compared with those available in GenBank™ using Basic Local Alignments Tool (BLAST) analyses. The study revealed for the first time the presence of TOSV in Lampedusa, Italy. The entomological studies directed on vectors are currently widely used in sand fly surveillance, and new data on TOSV are of public health concern.