Lymphocytic hypophysitis in dogs infected with Leishmania spp

Background

Morphological involvement of endocrine glands, such as the pituitary gland, remain uninvestigated in dogs with canine visceral leishmaniasis. Therefore, this study investigated the presence of amastigotes of Leishmania spp. and characterized inflammatory changes, highlighting the involvement of TCD3+ lymphocytes in different regions of the pituitary gland of dogs.

Methods

Samples were collected from 21 naturally infected dogs and 5 control, uninfected dogs. The different pituitary regions were analyzed in histological sections stained with hematoxylin and eosin (HE) under light microscopy. Inflammation was classified by intensity in a score from 0 to 3, absent (0), mild (1), moderate (2), and marked (3). The immunohistochemical (IHC) evaluation was performed in five high-power fields (hot spot) in a 40x objective of each region with manual counting (Image J1.52ª) of the TCD3+ lymphocytes and for amastigotes analyzed in 40x and 100x objectives. The Shapiro-Wilk test was used to assess the normality of the data. Differences between groups were determined by the Mann Whitney test. The correlation between variables was assessed by Sperman's correlation test. p < 0.05 were considered statistically significant.

Results

Amastigotes from the pituitary glands of two infected dogs were identified using IHC. The histopathological evaluation stained with hematoxylin and eosin showed greater intensity of inflammation in the pars distalis and pars intermedia regions of infected dogs. IHC for TCD3+ lymphocytes showed a higher median number of immunolabeled cells in pars nervosa in the infected group than in the control group (p < 0.05); and expecting a variation in the distribution and number of these cells in naturally infected dogs, the median of the control group was considered a cut-off point, an increase in T lymphocytes (p < 0.05) was also observed in the pars intermedia and pars distalis of an infected subgroup (n = 10). A moderate significant correlation between the intensity of inflammation and the number of immunolabeled TCD3+ lymphocytes was established in the analyzed pituitary regions, characterizing the occurrence of hypophysitis.

Conclusion

These findings presuppose that inflammation and/or the parasite in the pituitary region can result in gland dysfunction, worsening the clinical condition of the patient and compromising the efficiency of treatment and prognosis.

Increased CCL-5 (RANTES) Gene Expression in the Choroid Plexus of Dogs with Canine Leishmaniosis

Visceral canine leishmaniasis (CanL) can cause several clinical manifestations, including neurological lesions. Few reports have characterized the lesions observed in the central nervous system (CNS) during CanL; however, its pathogenesis remains unclear. The choroid plexus (CP) is a specialized structure responsible for the production and secretion of cerebrospinal fluid (CSF) and considered an interface between the peripheral immune system and CNS. It can allow the passage of inflammatory cells or pathogens and has the potential to act as a source of inflammatory mediators in several diseases. Thus, this study aimed to evaluate the role of CP as a possible route of inflammatory cells in the development of brain lesions in dogs with CanL, as well as its association with blood-CSF barrier (BCSFB) dysfunction. Samples were collected from 19 dogs that were naturally infected with CanL. We evaluated the histopathological lesions in the brain and investigated the gene expression of the cytokines. Capture enzyme-linked immunosorbent assay (ELISA) was used to evaluate the presence of the same cytokines in the CSF. Biochemical analysis was performed to compare the presence of albumin in the serum and CSF. Indirect ELISA was performed to measure the presence of anti-Leishmania antibodies in the CSF, which would suggest the disruption of the BCSFB. Histopathological evaluation of the dogs' brains revealed mild-to-severe inflammatory infiltrates, mainly in the CP and meninges. We also detected the presence of anti-Leishmania antibodies and albumin in the CSF, as well as Leishmania DNA in the CP. The gene expression of CCL-5 was increased in the CP of infected dogs compared with that of controls, and there was a tendency for the increase in the gene expression of CXCL-10. Thus, our findings confirm the disfunction of the BCSFB during CanL and suggest that the chemokines CCL-5 and CXCL-10 can be responsible for the recruitment of inflammatory cells found in CP.

Bronchoscopy and Lung Fine-Needle Aspiration for Antemortem Evaluation of Pulmonary Involvement in Dogs with Naturally Occurring Canine Leishmaniosis

Clinical manifestations from the lower respiratory tract are rare in canine leishmaniosis (CanL), making bronchoscopy and lung fine-needle aspiration (FNA) seldomly justified. The aim of this prospective study was to investigate the involvement of Leishmania infantum in the lungs of dogs with naturally occurring CanL by bronchoscopy and examination of bronchoalveolar lavage fluid (BALF), bronchial mucosa biopsies, and FNA, using immunodiagnostics. Dogs with relevant concurrent diseases and azotemia were excluded. Cough was detected in 5/31 (16.1%) dogs. Lesions (hyperemia, edema, mucosal granularity, secretions) were identified upon bronchoscopy in 19/31 (61.3%) dogs. The cytology of BALF revealed histiocytic inflammation in 14/31 (45.2%) dogs; the parasite was identified in one dog (3.2%). The immunofluorescence antibody test in BALF was positive in 15/31 (48.4%) dogs. Histopathology of bronchial mucosa and/or adjacent alveoli revealed lesions (mononuclear cell infiltration, fibrosis, edema, thickening of the inter-alveolar septa) in 24/31 (77.4%) dogs, with no Leishmania amastigotes. Positive antigen staining was observed within the cytoplasm of mononuclear cells in immunocytochemistry and immunohistochemistry. Μononuclear cells showed antigenic positivity in bronchial mucosa (27/31; 87.1%), BALF (30/31; 96.8%), and lung FNA (27/31; 87.1%). In conclusion, lungs seem to be affected from CanL more commonly than previously believed, and bronchoscopy allows obtaining valuable samples for antemortem diagnosis.

Role of Leishmania infantum in Meningoencephalitis of Unknown Origin in Dogs from a Canine Leishmaniosis Endemic Area

The main hypothesis for the aetiology of meningoencephalitis of unknown origin (MUO) in dogs is an autoimmune or genetic cause that is associated with a triggering event (environmental factors/infectious agents). The aim of this ambispective cohort study was to test for Leishmania infantum infection in the blood and cerebrospinal fluid (CSF) of dogs with MUO in an endemic area of canine leishmaniosis. Dogs with MUO were selected amongst all dogs undergoing blood anti-L. infantum antibody testing (control group). The blood plasma or serum samples from all dogs were analysed for anti- L. infantum antibodies by a quantitative indirect fluorescent assay (IFAT). In dogs with MUO, CSF samples were obtained for analysed by PCR detection of L. infantum DNA. Forty-four percent and 22% of the dogs in the MUO group featured magnetic resonance imaging (MRI) findings and CSF cytology respectively, consistent with L. infantum infection. IFAT, PCR, and histological findings were negative for L. infantum. A significant difference in L. infantum infection prevalence was found between the control and MUO group (p = 0.0022). While it seems unlikely that L. infantum plays a role in the aetiology of MUO, in endemic areas, this pathogen should be included in the differential diagnosis of this neurological disorder.

Visceral leishmaniasis in Saudi Arabia: From hundreds of cases to zero

The kingdom of Saudi Arabia (KSA) has succeeded in bringing the reported numbers of Visceral leishmaniasis (VL) cases from hundreds during the 1980s and 1990s to zero case in 2019. The endemicity of VL has been confined mainly to the Southwest regions, namely Jazan and Aseer regions. Leishmania donovani species have been identified as the causative species of VL, while L. infantum have been isolated only from dogs in the endemic areas. Many species of sand flies were caught in Southwest, but P. orientalis is the probable transmitter of the disease. The black rat (Rattus ratus) was found to be contributing to maintenance of the parasite life cycle. VL is primarily a disease of children, and 80% of cases were Saudi's, while cases from Yeminis nationality represent the majority of non- Saudi patients. The common clinical presentation consist of chronic fever, abdominal distention, weight loss, anemia and hepatosplenomegaly. Laboratory findings include: anemia, leukopenia, thrombocytopenia, hypoalbuminemia, hyperproteinaemia and hypergammaglobulinemia, low serum iron, and abnormal liver enzymes. Occurrence of jaundice has been identified as a bad prognostic sign. Diagnosis relying on direct smears from bone marrow aspirates was the commonest tool used, and also is advocated by the National Leishmaniasis Control Program (NLCP). Sodium stibogluconate (SSG) is the main drug used to treat VL cases, while Ambisome is preserved for complicated cases. Chemical control of sand flies using indoor residual spraying (IRS) with synthetic pyrethroids has been the most effective measure applied to prevent vector-human contact and disease transmission. The geographical overlap of VL and Malaria has facilitated the adoption and implementation of integrated vector control strategies. After reaching a zero case in 2019, the Ministry of Health (MoH) has a new commitment and facing a great challenge which are maintenance of current situation and elimination of VL. Through the support of stakeholders, encouragement of community participation, preparedness and readiness of leishmaniasis personnel, the new mission of the NLCP now is elimination of the scourge of VL from the country.

Comparative Pathology of the Peripheral Nervous System

The peripheral nervous system (PNS) relays messages between the central nervous system (brain and spinal cord) and the body. Despite this critical role and widespread distribution, the PNS is often overlooked when investigating disease in diagnostic and experimental pathology. This review highlights key features of neuroanatomy and physiology of the somatic and autonomic PNS, and appropriate PNS sampling and processing techniques. The review considers major classes of PNS lesions including neuronopathy, axonopathy, and myelinopathy, and major categories of PNS disease including toxic, metabolic, and paraneoplastic neuropathies; infectious and inflammatory diseases; and neoplasms. This review describes a broad range of common PNS lesions and their diagnostic criteria and provides many useful references for pathologists who perform PNS evaluations as a regular or occasional task in their comparative pathology practice.

Prognostic Factors and Life Expectancy in Canine Leishmaniosis

Canine leishmaniosis (CanL) is a chronic and potentially fatal disease. The prognosis of CanL depends on the severity of the clinical signs and clinicopathological abnormalities presented by the dog at the time of diagnosis. This study aims to estimate the survival time of dogs with CanL, determining the prognostic value of different clinical and clinicopathological parameters. Medical records of 99 dogs diagnosed with CanL in five veterinary centers of the Alentejo region (Portugal) were examined retrospectively. The majority of dogs presented hyperproteinemia, moderate normocytic normochromic anemia, normal blood urea and creatinine levels and were classified as stage 1 according to the International Interest Society (IRIS) guidelines at the time of diagnosis. The severity of anemia, presence of concomitant infectious diseases at the time of diagnosis and the anti-Leishmania therapy were correlated with the survival time. The influence of renal dysfunction was evaluated by Receiver Operating Characteristic (ROC) curve and survival analysis. Survival analysis demonstrated that patients classified as IRIS 1 at the time of diagnosis survived more than four years, in contrast with dogs classified as IRIS 2 that survived around two and half years and dogs classified as IRIS 3-4 that survived around one month. IRIS stage deteriorated during the course of CanL in one third of the dogs and was the principal cause of death or euthanasia in a high proportion of animals. In some cases, dogs did not receive anti-Leishmania treatment or abandoned the veterinary follow-ups, which may have considerable repercussions for animal wellbeing and public health. This study reinforces the value of blood urea and creatinine levels as prognostic factors in CanL.

Latest trends in L. infantum infection in dogs in Spain, Part II: current clinical management and control according to a national survey of veterinary practitioners

Background

Canine leishmaniosis (CanL) is a parasitic zoonotic disease, endemic in the Mediterranean basin including Spain. While knowledge about CanL, its management, treatment, prevention and control mounts, it remains unclear whether all clinical veterinarians follow the same international recommendations, such as those of the LeishVet group. This study was thus designed to assess recent trends in the clinical management of CanL in veterinary clinics across Spain through a questionnaire-based survey. Results were compared with those of a prior national multicenter questionnaire administered by our research team in 2005.

Methods

A questionnaire consisting of 28 questions about CanL was developed using Google Forms and distributed by email to 1428 veterinary clinics in Spain. Questions were designed to obtain data on common clinical signs, techniques and complementary exams used to diagnose the disease, and on its monitoring, treatment and control measures. Data were collected in a database for statistical analysis.

Results

Completed questionnaires were returned by 295 clinics. Compared to the situation in 2005, responses indicate that clinical signs of CanL have not changed significantly, cutaneous lesions being still the most prevalent sign observed by practitioners. Quantitative serological techniques are considered an adequate approach to diagnosis, provided their results are supported by the findings of a thorough physical exam, as well as complementary tests (complete blood count, biochemical profile, plasma protein electrophoretogram and complete urinalysis). Treatment protocols and check-ups follow international recommendations. Finally, a multimodal approach is being endorsed to adequately control CanL including preventive measures such as annual serological check-ups and the combination of repellents and vaccines. Additionally, owners are being better informed about CanL by veterinarians, which translates to the improved control of this zoonosis.

Conclusions

The clinical management of CanL has recently undergone significant changes owing to improvements in clinical knowledge of the disease, more unified international criteria, improved diagnostic techniques and their adequate interpretation, as well as a greater awareness of the disease transmitted to owners.

A pathological study of Leishmania infantum natural infection in European rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis)

In this study, we describe the pathology of Leishmania infantum infection in naturally infected wild Leporidae and compare diagnosis of infection using histopathology, direct fluorescent antibody (DFA) assay, immunofluorescence antibody test (IFAT) and quantitative real-time PCR (qPCR). Tissues were analysed from 52 European rabbits (Oryctolagus cuniculus) and 7 Iberian hares (Lepus granatensis) from the Community of Madrid (Spain). Our results show that L. infantum infection is associated with only minimal histopathological lesions and that L. infantum amastigotes can be detected by DFA assay in all tissues types tested, including skin. These results were confirmed by qPCR on fresh frozen tissues in 13% of rabbits and 100% of hares. However, L. infantum DNA could not be detected by qPCR on paraffin-embedded tissue obtained by laser capture microdissection. Using the DFA assay to diagnose L. infantum, infection may provide further insights into this disease in wild animals and may allow the precise tissue localization of L. infantum, thereby guiding follow-up tests with more accurate qPCR.

Leishmania hide-and-seek: Parasite amastigotes in the choroid plexus of a dog with neurological signs in an endemic municipality in Brazil

A female adult mixed-breed stray dog presented with hind limb paraparesis and clinical signs of visceral leishmaniasis. The cerebrospinal fluid presented signs of blood-brain barrier disruption. Both spleen and brain were positive for Leishmania spp. DNA. Besides inflammation, in situ hybridization and immunohistochemistry (IHC) revealed the presence of intracellular amastigotes in the choroid plexus (CP). Despite other studies that revealed parasite DNA, the current study describes the presence of Leishmania within the brain of a naturally infected dog, specifically in CP, with no previous reports in the Americas, and suggests the CP as a possible pathway to parasite entry into the brain.

Main lesions in the central nervous system of dogs due to Leishmania infantum infection

Background

Canine visceral leishmaniasis (CVL) is endemic in São Luís Maranhão/Brazil and it leads a varied clinical picture, including neurological signs.

Results

Histopathological evaluation showed that 14 dogs exhibited pathological alterations in at least one of the analyzed areas. Of these, mononuclear inflammatory reaction was the most frequent, although other lesions, such as hemorrhage, chromatolysis and gliosis were also observed. The presence of L. infantum amastigotes was confirmed in eight dogs, identified in four regions: telencephalon, hippocampus, thalamus and caudal colliculus, but only one presented neurological signs. Polymerase chain reaction results detected the DNA of the parasite in 11 samples from seven dogs. The positive areas were the telencephalon, thalamus, hippocampus, cerebellum, caudal and rostral colliculus.

Conclusion

These results reveal that during canine visceral leishmaniasis, the central nervous system may display some alterations, without necessarily exhibiting clinical neurological manifestations. In addition, the L. infantum parasite has the ability to cross the blood brain barrier and penetrate the central nervous system.

Unveiling Cerebral Leishmaniasis: parasites and brain inflammation in Leishmania donovani infected mice

Visceral leishmaniasis (VL) is a systemic disease with multifaceted clinical manifestations, including neurological signs, however, the involvement of the nervous system during VL is underestimated. Accordingly, we investigated both brain infection and inflammation in a mouse model of VL. Using bioluminescent Leishmania donovani and real-time 2D-3D imaging tools, we strikingly detected live parasites in the brain, where we observed a compartmentalized dual-phased inflammation pattern: an early phase during the first two weeks post-infection, with the prompt arrival of neutrophils and Ly6Chigh macrophages in an environment presenting a variety of pro-inflammatory mediators (IFN-γ, IL-1β, CXCL-10/CXCR-3, CCL-7/CCR-2), but with an intense anti-inflammatory response, led by IL-10; and a re-inflammation phase three months later, extremely pro-inflammatory, with novel upregulation of mediators, including IL-1β, TNF-α and MMP-9. These new data give support and corroborate previous studies connecting human and canine VL with neuroinflammation and blood-brain barrier disruption, and conclusively place the brain among the organs affected by this parasite. Altogether, our results provide convincing evidences that Leishmania donovani indeed infects and inflames the brain.

Neurological manifestations in dogs naturally infected by Leishmania infantum: descriptions of 10 cases and a review of the literature

In order to evaluate possible nervous system involvement in canine leishmaniasis, retrospective evaluation of all medical records of leishmaniotic dogs exhibiting neurological signs referred to our hospital over a 5-year period was performed. The records of 10 dogs were reviewed. Depending on the neuroanatomical localisation, the dogs underwent advanced diagnostic imaging, cerebrospinal fluid analysis, electrodiagnostic testing and histopathologic evaluations. The final neurological diagnosis was: meningoencephalitis (n=2), brain haemorrhagic stroke (n=1), haemorrhagic choroiditis (n=1), meningomyelitis (n=2), ischaemic myelopathy (n=1), polymyositis (n=2) and peripheral neuropathy (n=1). This study confirms that both central and peripheral nervous systems can be affected by leishmaniasis and provides an overview on the possible etiopathogenetic mechanisms. In addition, clinical and diagnostic findings, therapy and follow-up of affected dogs are described.

Occurrence of Leishmania infantum in the central nervous system of naturally infected dogs: Parasite load, viability, co-infections and histological alterations

Zoonotic visceral leishmaniasis is caused by the protozoan Leishmania infantum and little is known about the occurrence and pathogenesis of this parasite in the CNS. The aims of this study were to evaluate the occurrence, viability and load of L. infantum in the CNS, and to identify the neurological histological alterations associated with this protozoan and its co-infections in naturally infected dogs. Forty-eight Leishmania-seropositive dogs from which L. infantum was isolated after necropsy were examined. Cerebrospinal fluid (CSF) samples were analyzed by parasitological culture, quantitative real-time PCR (qPCR) and the rapid immunochromatographic Dual Path Platform test. Brain, spinal cord and spleen samples were submitted to parasitological culture, qPCR, and histological techniques. Additionally, anti-Toxoplasma gondii and anti-Ehrlichia canis antibodies in serum and distemper virus antigens in CSF were investigated. None of the dogs showed neurological signs. All dogs tested positive for L. infantum in the CNS. Viable forms of L. infantum were isolated from CSF, brain and spinal cord in 25% of the dogs. Anti-L. infantum antibodies were detected in CSF in 61% of 36 dogs. Inflammatory histological alterations were observed in the CNS of 31% of the animals; of these, 66% were seropositive for E. canis and/or T. gondii. Amastigote forms were associated with granulomatous non-suppurative encephalomyelitis in a dog without evidence of co-infections. The highest frequency of L. infantum DNA was observed in the brain (98%), followed by the spinal cord (96%), spleen (95%), and CSF (50%). The highest L. infantum load in CNS was found in the spinal cord. These results demonstrate that L. infantum can cross the blood-brain barrier, spread through CSF, and cause active infection in the entire CNS of dogs. Additionally, L. infantum can cause inflammation in the CNS that can lead to neurological signs with progression of the disease.

T lymphocyte immunophenotypes in the cerebrospinal fluid of dogs with visceral leishmaniasis

Visceral leishmaniasis (VL) is a disease causing several clinical manifestations in dogs, including neurological disorders. Nevertheless, there are few studies related to the evaluation of the brain alterations during VL. Evidences of the involvement of cerebral barriers in infected dogs was reported, including the presence of brain inflammatory infiltrate, with a predominance of CD3+ T cells. Therefore, the aim of this study was to determine the immunophenotypes of T lymphocytes in the cerebrospinal fluid (CSF), as well as in peripheral blood, and to correlate with brain alterations in dogs with VL. We detected elevated percentages of double negative (DN) and double positive (DP) T cells in the CSF, with a predominance of TCRαb. In the histopathological analysis, we observed a predominance of lymphoplasmacytic infiltrate, mainly in leptomeninges, ranging from mild to intense, and we observed a positive correlation between the intensity of inflammation in the subependymal area and the DN T cells of the CSF. Thus, the DN T cells seem be acting as villains of the immune system through pro-inflammatory mechanisms. Further, the proportion of the different population of CSF T cells did not differ from those observed in the blood, which provides us with more evidence of blood-CSF barrier breakdown. Together, the results provide more explanation to the inflammation observed in the brain of dogs with VL, which the DN T cells contribute to the origin and progression of the neurological disease. This study provides insight into the immunophenotypes of T lymphocytes in the CSF during canine visceral leishmaniasis.

Laboratory tests for diagnosing and monitoring canine leishmaniasis

Although several reviews on canine leishmaniasis have been published, none thoroughly described clinicopathologic abnormalities and their clinical usefulness. The aim of this review was to provide information concerning current diagnostic tests relevant for clinical pathologists and from a practical perspective. Specifically, in canine leishmaniasis, nonregenerative normocytic normochromic anemia, thrombocytopenia, or leukogram changes may be present. Clinical chemistry and urinalysis may indicate renal dysfunction (azotemia, decreased urine specific gravity, proteinuria) and an inflammatory/immune response (increased acute phase proteins [APP] or α₂ - and/or γ-globulins). Although a potential gammopathy is usually polyclonal, it may also appear oligo- or monoclonal, especially in dogs coinfected by other vector-borne pathogens. When lesions are accessible to fine-needle aspiration (lymphoadenomegaly, nodular lesions, joint swelling), cytology is strongly advised, as the presence of Leishmania amastigotes in a pattern of pyogranulomatous inflammation or lymphoplasmacytic hyperplasia is diagnostic. If the cytologic pattern is inconclusive, the parasite should be identified by histology/immunohistochemistry or PCR on surgical biopsies. Alternatively, cytology and PCR may be performed on bone marrow samples where amastigotes, along with erythroid hypoplasia, myeloid hyperplasia, plasmacytosis, or secondary dysmyelopoiesis can be observed. Dogs with overt leishmaniasis generally have high antibody titers, while low titers predominate in immunologically resistant infected dogs or in exposed dogs with no parasite confirmation. Quantitative serology is recommended in clinically suspect dogs as high-titer antibodies titers may confirm the clinical diagnosis. In confirmed and treated dogs, renal function and inflammatory/immune response variables should be periodically monitored.

Blood-brain barrier disruption during spontaneous canine visceral leishmaniasis

Visceral leishmaniasis is a complex disease caused by Leishmania infantum, and in dogs, besides the classical symptoms, there are descriptions of inflammatory alterations in the brain. Brain inflammation is a strictly controlled process, and as the brain counts on the efficiency of the blood-brain barrier (BBB), we aimed to assess BBB integrity in dogs with spontaneous visceral leishmaniasis. Therefore, we evaluated markers in the cerebrospinal fluid (CSF) and in brain tissue related to BBB disruption and brain inflammation. Elevated albumin quota revealed BBB breakdown, corroborated by increased concentrations of anti-Leishmania antibodies in the CSF. In the brain, albumin and IgG staining formed halos around blood vessels, a classical indicator of BBB leakage. Soluble IgG was also detected in the choroid plexus and ependyma, and in these structures, IgG stained random resident cells. IgG(+) cells and Fcγ-RI(+) cells were identified in the choroid plexus, ependyma and perivascular in the brain parenchyma. The data support the occurrence of BBB disruption in dogs with spontaneous visceral leishmaniasis, and IgG as a key molecule that is capable of initiating and/or maintaining the inflammatory stimuli in the nervous milieu and the CSF as an important disseminator of inflammatory stimuli within the CNS.

Seizures as a Consequence of Hyperviscosity Syndrome in Two Dogs Naturally Infected with Leishmania infantum

Serum hyperviscosity syndrome (HVS) was documented in two dogs with canine leishmaniasis (CanL) and seizures as the major clinical complaint. In both cases, laboratory abnormalities included mild non-regenerative anemia, thrombocytopenia, hypoalbuminemia, hyperproteinemia with monoclonal gammopathy, and marked serum hyperviscosity. CanL was diagnosed using cytology in one case and indirect immunofluorescence assay and conventional polymerase chain reaction in the second. Specific therapy with meglumine antimoniate and allopurinol(c) led to short-term remission in both dogs and normalization of serum viscosity. Although dogs rarely develop HVS, it should be suspected if hyperproteinemia and monoclonal gammopathy are present. Since CanL manifests with a variety of clinical presentations, including seizures resulting from HVS-induced central nervous system hypoxia, it should also be considered as a differential diagnosis in animals with seizures as a primary presenting sign.

Natural transmission of Leishmania infantum through experimentally infected Phlebotomus perniciosus highlights the virulence of Leishmania parasites circulating in the human visceral leishmaniasis outbreak in Madrid, Spain

A human leishmaniasis outbreak is occurring in the Madrid region, Spain, with the parasite and vector involved being Leishmania infantum and Phlebotomus perniciosus respectively. The aim of this study was to investigate the virulence of L. infantum isolates from the focus using a natural transmission model. Hamsters were infected by intraperitoneal inoculation (IP) or by bites of sand flies experimentally infected with L. infantum isolates obtained from P. perniciosus collected in the outbreak area (IPER/ES/2012/BOS1FL1 and IPER/ES/2012/POL2FL6) and a well characterized L. infantum strain JPCM5 (MCAN/ES/98/LLM-877). Hamster infections were monitored by clinical examination, serology, culture, parasite burden, Giemsa-stained imprints, PCR, histopathology and xenodiagnostic studies. Establishment of infection of L. infantum was achieved with the JPCM5 strain and outbreak isolates by both P. perniciosus infective bites or IP route. However, high virulence of BOS1FL1 and POL2FL6 isolates was highlighted by the clinical outcome of disease, high parasite detection in spleen and liver, high parasitic loads and positivity of Leishmania serology. Transmission by bite of POL2FL6 infected flies generated a slower progression of clinical disease than IP infection, but both groups were infective to P. perniciosus by xenodiagnosis at 2 months post-infection. Conversely, hamsters inoculated with JPCM5 were not infective to sand flies. Histopathology studies confirmed the wide spread of POL2FL6 parasites to several organs. A visceral leishmaniasis model that mimics the natural transmission in nature allowed us to highlight the high virulence of isolates that are circulating in the focus. These findings contribute to a better understanding of the outbreak epidemiology.

Leishmaniosis of companion animals in Europe: an update

Leishmaniosis caused by Leishmania infantum is a vector-borne zoonotic disease endemic in southern Europe, but which is spreading northwards. Millions of dogs, cats and other non-conventional companion animals susceptible to L. infantum, living in European households, may develop a severe disease and contribute to the spread of leishmaniosis because of travelling or re-homing. Dogs are the main reservoir but other new reservoirs have recently been incriminated. Sand flies remain the sole proven vector and non-vectorial transmission has been reported at individual level and in areas where the vector is absent. Clinical disease affects only a proportion of infected dogs and a complex genetic background of immune response is responsible for this susceptibility. There is a wide range of serological and parasitological diagnostic tools available whose cost-effective use depends on a reasoned approach. Clinical response to treatment of sick dogs is variable. Clinical cure is often obtained but clinical recurrence can occur and post-therapy follow up should be maintained life-long. In Europe, vaccination can be combined with individual protection with pyrethroids as part of an integrated approach to prevention. L. infantum is the only species isolated from cats in Europe and xenodiagnosis substantiated that infected cats are infectious for sand flies. Feline infection may be frequent in endemic areas, but prevalence is generally lower than in dogs. When cats are tested by both serological and molecular techniques discordant results are often observed. Feline cases have been reported from endemic areas in Italy, France, Spain and Portugal, but four cases were also diagnosed in Switzerland in cats that had travelled to or been imported from Spain. Half of the cases were diagnosed in cats with impaired immune responses. Clinical manifestations compatible with feline leishmaniosis include lymph node enlargement, skin and mucocutaneous lesions, ocular lesions, chronic gingivostomatitis, hypergammaglobulinemia, and normocytic normochromic anemia. Cats have been empirically treated with some drugs used in dogs. Due to polymorphic clinical picture and the insidious progressive course, leishmaniosis can persist for a long time before dogs or cats are brought to a veterinarian and so diagnosis can be delayed. Exotic or new Leishmania spp. have been reported in humans, animals and vectors in Europe. This changing situation requires attention in Europe for designing epidemiological studies and control measures.

Intramedullary spinal cord mass presumptively associated with leishmaniasis in a dog

CASE DESCRIPTION

A 9-year-old male Miniature Poodle was evaluated because of progressive severe right hemiparesis, right forelimb lameness, and signs of cervical pain.

CLINICAL FINDINGS

A low body condition score (2/9) and popliteal lymphadenopathy were detected. Results of a CBC, serum biochemical analyses, urinalysis, cytologic examination of bone marrow and popliteal lymph node aspirates, and serum ELISA were consistent with systemic leishmaniasis. Magnetic resonance imaging of the cervical spinal cord revealed an intramedullary mass extending from the caudal aspect of the C5 vertebral body to the C5-6 intervertebral disk space with a contrast medium-enhanced pattern that had 3 zones (central contrast medium-enhanced core, intermediate isointense zone, and peripheral contrast medium-enhanced ring). Surgical biopsy of the mass was performed by means of a right C5-6 dorsal hemilaminectomy. Results of PCR assays for detection of Leishmania DNA in CSF and tissue biopsy samples were positive.

TREATMENT AND OUTCOME

Treatment for systemic leishmaniasis was initiated. Two months later, body condition, neurologic signs, and gait of the dog had substantially improved; the dog had mild right forelimb paresis at that time. Results of follow-up MRI indicated resolution of the cervical spinal cord lesion. Four months after diagnosis, the dog's neurologic condition was stable.

CLINICAL RELEVANCE

To the authors' knowledge, this report is the first in which clinical findings, clinicopathologic data, and MRI characteristics of an intramedullary inflammatory spinal cord lesion presumptively attributable to leishmaniasis in a dog have been reported, and the first report of CNS leishmaniasis in a dog with MRI resolution and a successful clinical response to treatment.

Immunocytochemical demonstration of feline infectious peritonitis virus within cerebrospinal fluid macrophages

A 4-month-old female entire domestic shorthair cat presented with an acute onset of blindness, tetraparesis and subsequent generalised seizure activity. Haematology and serum biochemistry demonstrated a moderate, poorly regenerative anaemia, hypoalbuminaemia and hyperglobulinaemia with a low albumin:globulin ratio. Serology for feline coronavirus antibody was positive with an elevated alpha-1 acid glycoprotein. Analysis of cisternal cerebrospinal fluid (CSF) demonstrated markedly elevated protein and a mixed, predominately neutrophilic pleocytosis. Immunocytochemistry for feline coronavirus was performed on the CSF, with positive staining observed inside macrophages. The cat was subsequently euthanased, and both histopathology and immunohistochemistry were consistent with a diagnosis of feline infectious peritonitis. This is the first reported use of immunocytochemistry for detection of feline coronavirus within CSF macrophages. If this test proves highly specific, as for identification of feline coronavirus within tissue or effusion macrophages, it would be strongly supportive of an ante-mortem diagnosis of feline infectious peritonitis in cats with central nervous system involvement without the need for biopsy.