Leishmania infantum infection rate in dogs housed in open-admission shelters is higher than of domiciled dogs in an endemic area of canine visceral leishmaniasis. Epidemiological implications.

Canine visceral leishmaniasis (CVL) is caused by Leishmania infantum and is endemic in many areas of southeastern Brazil. We have hypothesized that the prevalence of infection by L. infantum in dogs housed in open-admission animal shelters is beyond the range of 3.4 - 9.6% reported among dogs domiciled in similar CVL-endemic areas. Hence, this study aimed to determine the rate of L. infantum infection among dogs maintained in shelters and to investigate the epidemiology of CVL in such environments by analyzing hematological and biochemical parameters. A total of 627 dogs from 17 different shelters across the State of Minas Gerais were screened using the Dual-Path Platform test and enzyme-linked immunosorbent assay and 211 (33.6%) were found to be seropositive in both tests. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed on skin, bone marrow and lymphoid tissues of 118 seropositive dogs with inconclusive CVL clinical diagnosis and, of these, 78 (66.1%) were PCR+ for L. infantum and 7 (5.9%) were PCR+ for L. amazonensis. One dog presented a PCR-RFLP profile that was consistent with co-infection by both parasites. Leishmania amazonensis DNA was detected in skin samples of six single-infected dogs and this constitutes a novel finding. Dogs infected only with L. amazonensis were less debilitated than those infected by L. infantum, which showed typical clinical manifestations of CVL. The co-infected dog showed only mild clinical signs. The results presented herein not only support our original hypothesis but also suggest that dogs are potential reservoirs of L. amazonensis. Public health authorities should acknowledge their responsibility towards animals in collective shelters, recognize that they are potential foci of zoonotic diseases, and establish proper functioning directives to minimize transmission to humans and to other dogs.

In Vivo Cardiotoxic Potential of Micrurus frontalis Venom.

In the present study, we investigated the cardiotoxic potential of Micrurus frontalis venom. Twelve guinea pigs (Cavia porcellus) were distributed in two groups (n = 6), named control and envenomed. Control groups received 0.2 ml of PBS/BSA, while envenomed group received 0.2 ml of the same solution containing 450 µg/kg of M. frontalis venom. Both were intramuscular injections. Electrocardiography, echocardiogram, blood count, and serum biochemistry were performed before and 2 h after inoculation. Necropsy was performed, and histological and ultrastructural analysis of the heart were conducted. First clinical signs were presented as early as 18 min after venom inoculation. All poisoned animals presented flaccid paralysis of both hind and forelimbs, followed by fasciculations and respiratory arrythmia. However, the animals did not die in the first 2 h of poisoning. ECG of the poisoned animals revealed severe ventricular arrythmias, corroborated by reduction of both ejection and shortening fractions, increase in CK, CK-MB, troponin, cardiomyocyte degeneration, fragmentation and mitochondrial damage. M. frontalis venom causes severe heart damage, eliciting both morphological and arrhythmogenic effects after only 2 h of envenomation.

Characterization of proteinuria in treated and untreated dogs naturally infected with Leishmania sp

ABSTRACT: In the search for an early biomarker of renal injury, this study aimed to determine the urinary protein profile of dogs with leishmaniasis without treatment and treated as determined by Brazilian legislation. The identification of proteinuria, its classification and the circumstances in which it takes place instigated this study. For this, 30 dogs from an outpatient clinic at a Veterinary Hospital in Belo Horizonte were evaluated. All animals underwent clinical and laboratory tests, which included renal biomarkers. The proteins were characterized using the SDS-page electrophoresis technique, and thus, a urinary protein profile was developed comparing patients considered clinically healthy with dogs infected with leishmaniasis that were under treatment and with untreated infected dogs. The results showed that the hematological and biochemical parameters showed similar behavior between the groups of healthy dogs and dogs with leishmaniasis treated, however a very heterogeneous pattern of urinary proteins can be observed and differed between healthy animals and animals with leishmaniasis, as well as between treated and untreated animals. The results suggest that the classification of proteinuria can be a tool that helps in the staging of animals infected with L. infantum and can differentiate them as to the severity of existing kidney injuries.

RESUMO: Na busca por um biomarcador precoce de injúria renal, este trabalho teve como objetivo determinar o perfil proteico urinário de cães infectados com leishmaniose sem tratamento e tratados conforme determina a legislação brasileira. A identificação da proteinúria, sua classificação e as circunstâncias em que ocorrem instigaram este estudo. Para tanto, foram avaliados 30 cães oriundos do atendimento clínico ambulatorial de um Hospital Veterinário em Belo Horizonte. Todos os animais passaram por exame clínico e laboratorial, que incluíram biomarcadores renais. As proteínas foram caracterizadas através da técnica de eletroforese por SDS-PAGE, e assim, foi elaborado um perfil proteico urinário comparando pacientes considerados clinicamente hígidos, com cães infectados por Leishmania (L.) infantum e que estavam sob tratamento e cães infectados não tratados. Os resultados demonstraram que os parâmetros hematológicos e bioquímicos apresentaram comportamento semelhante entre os grupos de cães hígidos e de cães infectados com L. infantum tratados, entretanto um padrão muito heterogêneo de proteínas urinárias pode ser observado e diferiu entre animais hígidos e animais com leishmaniose, assim como entre os animais tratados e não tratados. Os resultados sugerem que a classificação da proteinúria pode ser uma ferramenta que auxilia no estadiamento de animais infectados por L. infantum podendo diferenciá-los quanto à gravidade de lesões renais existentes.

Characterization of proteinuria in treated and untreated dogs naturally infected with Leishmania sp / Caracterização da proteinúria de cães tratados e não tratados, naturalmente infectados com Leishmania sp

In the search for an early biomarker of renal injury, this study aimed to determine the urinary protein profile of dogs with leishmaniasis without treatment and treated as determined by Brazilian legislation. The identification of proteinuria, its classification and the circumstances in which it takes place instigated this study. For this, 30 dogs from an outpatient clinic at a Veterinary Hospital in Belo Horizonte were evaluated. All animals underwent clinical and laboratory tests, which included renal biomarkers. The proteins were characterized using the SDS-page electrophoresis technique, and thus, a urinary protein profile was developed comparing patients considered clinically healthy with dogs infected with leishmaniasis that were under treatment and with untreated infected dogs. The results showed that the hematological and biochemical parameters showed similar behavior between the groups of healthy dogs and dogs with leishmaniasis treated, however a very heterogeneous pattern of urinary proteins can be observed and differed between healthy animals and animals with leishmaniasis, as well as between treated and untreated animals. The results suggest that the classification of proteinuria can be a tool that helps in the staging of animals infected with L. infantum and can differentiate them as to the severity of existing kidney injuries.(AU)

Na busca por um biomarcador precoce de injúria renal, este trabalho teve como objetivo determinar o perfil proteico urinário de cães infectados com leishmaniose sem tratamento e tratados conforme determina a legislação brasileira. A identificação da proteinúria, sua classificação e as circunstâncias em que ocorrem instigaram este estudo. Para tanto, foram avaliados 30 cães oriundos do atendimento clínico ambulatorial de um Hospital Veterinário em Belo Horizonte. Todos os animais passaram por exame clínico e laboratorial, que incluíram biomarcadores renais. As proteínas foram caracterizadas através da técnica de eletroforese por SDS-PAGE, e assim, foi elaborado um perfil proteico urinário comparando pacientes considerados clinicamente hígidos, com cães infectados por Leishmania (L.) infantum e que estavam sob tratamento e cães infectados não tratados. Os resultados demonstraram que os parâmetros hematológicos e bioquímicos apresentaram comportamento semelhante entre os grupos de cães hígidos e de cães infectados com L. infantum tratados, entretanto um padrão muito heterogêneo de proteínas urinárias pode ser observado e diferiu entre animais hígidos e animais com leishmaniose, assim como entre os animais tratados e não tratados. Os resultados sugerem que a classificação da proteinúria pode ser uma ferramenta que auxilia no estadiamento de animais infectados por L. infantum podendo diferenciá-los quanto à gravidade de lesões renais existentes.(AU)

Vaccination against canine leishmaniosis increases the phagocytic activity, nitric oxide production and expression of cell activation/migration molecules in neutrophils and monocytes.

Visceral leishmaniasis (VL) is transmitted by phlebotomine sandfly vectors and domestic dogs serve as a reservoir. The elimination of seropositive dogs has been a recommended strategy for managing the disease in Brazil. A protective canine vaccine would be an important tool for controlling the disease, reducing the parasites available to sandfly vectors and, consequently, reducing the number of human VL cases. Leishmune(®) is an anti-canine Leishmaniosis (VL Canine) vaccine produced by Zoetis (Pfizer, Brazil) that was commercially available in Brazil until 2014. The main goal of the present study was to investigate the protective immunological events induced by vaccination with Leishmune(®) in the time frame of one year. Healthy, non-vaccinated dogs and dogs of 1, 6 and 10 months post-vaccination were evaluated. Results showed that Leishmune(®) induced an increase in phagocytic activity of neutrophils and monocytes and also increased NO production. Immunological events were correlated with functional responses, as high levels of IgG and an increase of the receptor Fcγ were detected. Vaccination induced an increased expression of TLR (2, 4, 5, 9), integrin (CD29, CD49f), activation (MHCII) and co-stimulatory (CD80, CD81) molecules by neutrophils and monocytes. Vaccination led to decrease of IL-4 and an increase of IL-8 production by monocytes and higher IFN-γ and IL-17 production by T-cells. The results suggested that Leishmune(®) was able to induce a long-lasting change in immune response, mediated by supportive immunological events that may be participating in protective immunity against CL.

One-year timeline kinetics of cytokine-mediated cellular immunity in dogs vaccinated against visceral leishmaniasis.

BACKGROUND: The main control strategy for visceral leishmaniasis in Brazil has been based on the elimination of seropositive dogs, although this is not widely accepted. In this context, the use of a long-lasting protective vaccine against canine visceral leishmaniasis (CVL) has been highly expected. The aim of this work was to determine the timeline kinetics of the cytokine microenvironment derived from circulating leukocytes as supportive immunological biomarkers triggered by Leishmune® vaccine. Cross-sectional kinetic analysis of cellular immunity cytokines was carried out at three times (1, 6 and 12 months) after primovaccination with Leishmune®. In vitro short-term whole blood cultures were stimulated with Leishmania infantum soluble antigen (SLAg). The secreted cytokine signatures and their major sources were determined. RESULTS: At six months after vaccination, Leishmune® induced an increase in IL-8, IFN-γ, IL-17a and TNF-α levels and a decrease in IL-10. Cytokine signature analysis revealed a shift in the microenvironment towards a pro-inflammatory profile mediated by IL-8 and IFN-γ. Both, CD4(+) (↑TNF-α(+) and ↑IFN-γ (+)) and CD8(+) (↑IL-17a and ↓IL-4) T-cells contributed to the acquired immune responses observed after stimulation with SLAg. CONCLUSIONS: The changes observed in the cytokine profile suggested that Leishmune® was able to induce an effective response at six months after primovaccination. After one year, it returned to baseline suggesting the need of additional boosting.

Bronchoalveolar lavage as a tool for evaluation of cellular alteration during Aelurostrongylus abstrusus infection in cats / Lavado broncoalveolar como ferramenta para avaliação de alterações celulares durante a infecção por Aelurostrongylus abstrusus em gatos

Bronchoalveolar lavage (BAL) is a procedure that retrieves cells and other elements from the lungs for evaluation, which helps in the diagnosis of pulmonary diseases. The aim of this study was to perform this procedure for cellular analysis of BAL fluid alterations during experimental infection with Aelurostrongylus abstrusus in cats. Fourteen cats were individually inoculated with 800 third stage larvae of A. abstrusus and five non-infected cats lined as a control group. The BAL procedure was performed through the use of an endotracheal tube on the nineteen cats with a mean age of 18 months, on 0, 30, 60, 90, 120, 180 and 270 days after infection. Absolute cell counts in the infected cats revealed that alveolar macrophages and eosinophils were the predominant cells following infection. This study shows that the technique allows us to retrieve cells and first stage larvae what provides information about the inflammatory process caused by aelurostrongylosis.

O lavado broncoalveolar (LBA) é um procedimento que permite a recuperação de células e outros elementos pulmonares para avaliação, auxiliando no diagnóstico de doenças pulmonares. O objetivo do presente trabalho foi realizar este procedimento para avaliação das células presentes no fluido broncoalveolar na infecção experimental por Aelurostrongylus abstrusus em gatos. Quatorze animais foram individualmente inoculados com 800 larvas de terceiro estádio de A. abstrusus, enquanto cinco animais não infectados foram mantidos como grupo controle. O LBA foi realizado com uso de um tubo endotraqueal em todos os 19 animais com média de idade de 18 meses, nos dias nos dias 0, 30, 60, 90, 120, 180 e 270 após infecção. A contagem absoluta de células dos animais infectados revelou que macrófagos alveolares e eosinófilos constituíram os tipos celulares predominantes durante todo o período de infecção. Os resultados deste trabalho demonstram que a técnica permite recuperar células e larvas de primeiro estádio de A. abstrusus, fornecendo informações importantes sobre o processo inflamatório causado na aelurostrongilose.