RESUMO
Rabies is an ancient neuroinvasive viral (genus Lyssavirus, family Rhabdoviridae) disease affecting approximately 59,000 people worldwide. The central nervous system (CNS) is targeted, and rabies has a case fatality rate of almost 100% in humans and animals. Rabies is entirely preventable through proper vaccination, and thus, the highest incidence is typically observed in developing countries, mainly in Africa and Asia. However, there are still cases in European countries and the United States. Recently, demographic, increasing income levels, and the coronavirus disease 2019 (COVID-19) pandemic have caused a massive raising in the animal population, enhancing the need for preventive measures (e.g., vaccination, surveillance, and animal control programs), postexposure prophylaxis, and a better understanding of rabies pathophysiology to identify therapeutic targets, since there is no effective treatment after the onset of clinical manifestations. Here, we review the neuroimmune biology and mechanisms of rabies. Its pathogenesis involves a complex and poorly understood modulation of immune and brain functions associated with metabolic, synaptic, and neuronal impairments, resulting in fatal outcomes without significant histopathological lesions in the CNS. In this context, the neuroimmunological and neurochemical aspects of excitatory/inhibitory signaling (e.g., GABA/glutamate crosstalk) are likely related to the clinical manifestations of rabies infection. Uncovering new links between immunopathological mechanisms and neurochemical imbalance will be essential to identify novel potential therapeutic targets to reduce rabies morbidity and mortality.
Assuntos
Vírus da Raiva , Raiva , Humanos , Animais , Estados Unidos , Raiva/epidemiologia , Vacinação , Europa (Continente) , Resultado do Tratamento , Profilaxia Pós-Exposição/métodosRESUMO
Visceral leishmaniosis (VL) is a multisystem disease that affects domestic dogs and can have several clinical manifestations, including some rare reports of neurological clinical signs, or it may remain asymptomatic, depending on the individual immune response against the Leishmania parasite. VL involves immune system sensors, such as the Toll-like receptors (TLRs), that are related to innate immunity and inflammation. Previously, we have reported the presence of brain inflammation in infected dogs. Here, we investigated the gene expression profile of TLRs 1-10 in the brain and the spleen of infected dogs, along with the production of proinflammatory cytokines (TNF-α, IFN-γ, IL-1ß and IL-6) with the aim of explaining the origin of brain inflammation. The gene expression of TLRs has varied according to the tissue evaluated. In the brain, TLR-4 was only up-regulated in a small subpopulation of infected dogs, while in the spleen, we detected an increase in TLR-5 and TLR-9 transcripts, as well as a reduction in TLRs 2-4 and TLR-10. All cytokines except IL-6 were detected in infected dogs. Moreover, we detected Leishmania DNA in all infected dogs in both tissues evaluated. In the histopathological analysis, we observed a predominance of lymphoplasmacytic infiltrate, mainly in leptomeninges and choroid plexuses, ranging from mild to intense. This study provides the first insight into the TLRs profile in the brain and the spleen during canine VL and provides support to confirm the involvement of sensors of the innate immune system sensors against L. infantum parasites.
Assuntos
Citocinas/genética , Doenças do Cão/patologia , Leishmania infantum/fisiologia , Leishmaniose Visceral/veterinária , Receptores Toll-Like/genética , Animais , Encéfalo/parasitologia , Encéfalo/patologia , Doenças do Cão/parasitologia , Cães , Feminino , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/patologia , Masculino , Baço/parasitologia , Baço/patologiaRESUMO
The skin is the first organ to be infected by the parasite in canine visceral leishmaniasis. The enzyme matrix metalloproteinase (MMP) acts towards degradation of the extracellular matrix (ECM) and modulation of the inflammatory response against many kinds of injuries. The aims of this study were to evaluate the expression of MMP-2 and MMP-9 through immunohistochemistry and zymography on the skin (muzzle, ears, and abdomen) of dogs that were naturally infected by Leishmania spp. and to compare these results with immunodetection of the parasite and with alterations to the dermal ECM. Picrosirius red staining was used to differentiate collagen types I and III in three regions of the skin. The parasite load, intensity of inflammation, and production of MMP-2 (latent) and MMP-9 (active and latent) were higher in the ear and muzzle regions. MMP-9 (active) predominated in the infected group of dogs and its production was significantly different to that of the control group. Macrophages, lymphocytes, and plasma cells predominated in the dermal inflammation and formed granulomas in association with degradation of mature collagen (type I) and with discrete deposition of young collagen (type III). This dermal change was more pronounced in dogs with high parasite load in the skin. Therefore, it was concluded that the greater parasite load and intensity of inflammation in the skin led consequently to increased degradation of mature collagen, caused by increased production of MMPs, particularly active MMP-9, in dogs with visceral leishmaniasis. This host response profile possibly favors systemic dissemination of the parasite.
Assuntos
Doenças do Cão/patologia , Leishmaniose Visceral/veterinária , Metaloproteinase 2 da Matriz/biossíntese , Metaloproteinase 9 da Matriz/biossíntese , Pele/patologia , Abdome/parasitologia , Abdome/patologia , Animais , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Doenças do Cão/parasitologia , Cães , Orelha/parasitologia , Orelha/patologia , Matriz Extracelular/metabolismo , Inflamação/imunologia , Inflamação/parasitologia , Leishmania infantum/imunologia , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/patologia , Linfócitos/imunologia , Macrófagos/imunologia , Boca/parasitologia , Boca/patologia , Nariz/parasitologia , Nariz/patologia , Carga Parasitária , Plasmócitos/imunologia , Pele/parasitologiaRESUMO
Some studies have shown the role played by matrix metalloproteinases and their inhibitors in doxorubicin cardiotoxicity. In this study, we sought to investigate how plasma and myocardial MMP 2 and 9 perform in rabbits with doxorubicin-induced cardiomyopathy, searching for a correlation between the activity of these collagenases and cardiac remodeling. Cardiomyopathy was induced by doxorubicin given intravenously twice a week for six consecutive weeks. Plasma MMP activity and the echocardiogram were assessed at baseline, and at 15 and 45 days after first injection of doxorubicin. The myocardial activity of these enzymes was solely evaluated in nine rabbits at 45 days, and results were compared with nine healthy controls. We only identified the full-length forms of both MMP 2 and 9 throughout the study. The plasma pro-MMP 2 reduced along the deterioration of cardiac function, while the pro-MMP 9 increased significantly at T45 as compared to baseline and T15. A negative significant correlation was found to exist between the plasma activity of pro-MMP 2 and mitral E-to-mitral septal annular early diastolic velocity ratio, which is an estimate of mean left atrial pressure and congestion. Only pro-MMP 2 was found in myocardial samples, and mean activity of such enzyme was statistically lower than that recorded for healthy controls. Although no active form was documented for either collagenase, the duration of the treatment with doxorubicin played a role in the alteration of plasma pro-forms activity. However, these changes could not be associated with most echocardiographic parameters that are supportive of cardiac remodeling.(AU)
Alguns estudos já demonstraram o papel exercido pelas metaloproteinases de matriz e seus inibidores na cardiotoxicidade promovida pela doxorrubicina. Assim, este estudo teve como objetivo investigar o comportamento das MMPs 2 e 9 plasmáticas e miocárdicas em coelhos com cardiomiopatia induzida pela doxorrubicina, buscando determinar se há correlação entre a atividade dessas colagenases e o remodelamento cardíaco. A cardiomiopatia foi induzida pela doxorrubicina aplicada por via intravenosa duas vezes por semana ao longo de seis semanas consecutivas. A atividade plasmática das MMPs e o ecocardiograma foram avaliados no momento basal e aos 15 e 45 dias após a primeira aplicação da doxorrubicina. A atividade miocárdica dessas enzimas foi quantificada em apenas nove coelhos aos 45 dias e os resultados comparados com outros nove controles saudáveis. Foram identificadas apenas as formas inativas das MMPs 2 e 9 durante todo o estudo. A pro-MMP 2 plasmática reduziu à medida que a função cardiaca se deteriorou, enquanto a pro-MMP 9 aumentou significativamente em T45 quando comparada aos momentos basal e T15. Houve correlação negativa significativa entre a atividade plasmática da pro-MMP 2 e a relação entre E mitral e a velocidade anular mitral no início da diástole, um parâmetro que permite estimar a pressão atrial esquerda média e a congestão. Apenas a pro-MMP 2 foi documentada nas amostras miocárdicas dos coelhos com cardiomiopatia e atividade media dessa enzima foi estatisticamente menor que aquela observada nos controles saudáveis. Embora a forma ativa de ambas as colagenases não tenha sido identificada, o tempo de tratamento com doxorrubicina interferiu na atividade das formas inativas plasmáticas. Contudo, essas alterações não se associaram com a maioria dos parâmetros ecocardiográficos que indicam remodelamento cardíaco.(AU)
Assuntos
Animais , Coelhos , Doxorrubicina/toxicidade , Metaloproteinase 2 da Matriz/análise , Metaloproteinase 9 da Matriz/análise , Cardiomiopatias/veterinária , Colagenases , Ecocardiografia/veterináriaRESUMO
The aim of this study was to investigate the occurrence of Tritrichomonas foetus in cats in the area surrounding the city of Araçatuba municipality, State of São Paulo, Brazil. Fecal samples from 129 cats were collected by rectal flush technique. It was compared two diagnosis methods, direct examination of feces and PCR. The presence of T. foetus DNA was verified using PCR by amplification of 347-bp fragment from the primers TFR3 and TFR4 and amplicons of positive cases were sequenced. Statistical analyses were performed investigating the associations between T. foetus infection with gender, age, breed, presence of diarrhea and/or history of diarrhea, previous treatment, lifestyle, origin, environment, and co-infection. T. foetus was observed in one sample (n=129) by direct microscopic examination of feces while PCR was positive in five samples (3.9%). Giardia species and Cryptosporidium species co-infection was also observed. Statistical analyses showed no significant associations between T. foetus infection and all listed factors, although most positive cats were asymptomatic and lived in multi-cat household. The isolates of T. foetus showed 100% identical sequences with other T. foetus isolates from cats around the world. So, the occurrence of T. foetus was confirmed in cats in Araçatuba city (Brazil). This parasite must be considered as a differential diagnosis in cats with diarrhea and also in asymptomatic carriers as source of infection in multi-cat environments.(AU)
O objetivo deste estudo foi investigar a ocorrência de Tritrichomonas foetus em gatos na região do município de Araçatuba, SP, Brasil. Foram coletadas amostras fecais de 129 gatos através da técnica de lavado retal. Dois métodos diagnósticos foram comparados, o exame direto das fezes e a PCR. A presença de DNA de T. foetus foi verificada por meio da PCR através da amplificação de 347 pares de bases a partir dos iniciadores específicos TFR3 e TFR4. Posteriormente, os resultados amplificados das amostras positivas foram sequenciadas. Também foi feita análise estatística a fim de investigar a correlação entre infecção por T. foetus e sexo, idade, raça, presença e/ou histórico de diarreia, tratamento prévio, coinfecção, estilo de vida, origem e tipo de ambiente. O protozoário pôde ser observado em uma amostra através do exame direto das fezes e à PCR foram detectadas cinco amostras positivas (3.9%). Foram detectadas coinfecções por Giardia spp. e Cryptosporidium spp. Não foram observadas correlações entre infecção por T. foetus e todos os fatores listados anteriormente, embora a maioria dos felinos positivos fossem assintomáticos e vivessem em ambientes multigatos. O resultado do sequenciamento genético dos isolados das amostras positivas mostrou 100% de similaridade com outros isolados de felinos no mundo. Assim, a ocorrência de T. foetus foi confirmada em gatos em Araçatuba, São Paulo, Brasil. Sendo assim, o parasito deve considerado como diagnóstico diferencial em gatos com diarreia assim como em portadores assintomáticos como fontes de infecção em ambientes multigatos.(AU)
Assuntos
Animais , Gatos , Infecções por Protozoários/diagnóstico , Tritrichomonas foetus/isolamento & purificação , Brasil , Diarreia/etiologia , Doenças Parasitárias/diagnóstico , Reação em Cadeia da Polimerase/veterináriaRESUMO
Some studies have shown the role played by matrix metalloproteinases and their inhibitors in doxorubicin cardiotoxicity. In this study, we sought to investigate how plasma and myocardial MMP 2 and 9 perform in rabbits with doxorubicin-induced cardiomyopathy, searching for a correlation between the activity of these collagenases and cardiac remodeling. Cardiomyopathy was induced by doxorubicin given intravenously twice a week for six consecutive weeks. Plasma MMP activity and the echocardiogram were assessed at baseline, and at 15 and 45 days after first injection of doxorubicin. The myocardial activity of these enzymes was solely evaluated in nine rabbits at 45 days, and results were compared with nine healthy controls. We only identified the full-length forms of both MMP 2 and 9 throughout the study. The plasma pro-MMP 2 reduced along the deterioration of cardiac function, while the pro-MMP 9 increased significantly at T45 as compared to baseline and T15. A negative significant correlation was found to exist between the plasma activity of pro-MMP 2 and mitral E-to-mitral septal annular early diastolic velocity ratio, which is an estimate of mean left atrial pressure and congestion. Only pro-MMP 2 was found in myocardial samples, and mean activity of such enzyme was statistically lower than that recorded for healthy controls. Although no active form was documented for either collagenase, the duration of the treatment with doxorubicin played a role in the alteration of plasma pro-forms activity. However, these changes could not be associated with most echocardiographic parameters that are supportive of cardiac remodeling.(AU)
Alguns estudos já demonstraram o papel exercido pelas metaloproteinases de matriz e seus inibidores na cardiotoxicidade promovida pela doxorrubicina. Assim, este estudo teve como objetivo investigar o comportamento das MMPs 2 e 9 plasmáticas e miocárdicas em coelhos com cardiomiopatia induzida pela doxorrubicina, buscando determinar se há correlação entre a atividade dessas colagenases e o remodelamento cardíaco. A cardiomiopatia foi induzida pela doxorrubicina aplicada por via intravenosa duas vezes por semana ao longo de seis semanas consecutivas. A atividade plasmática das MMPs e o ecocardiograma foram avaliados no momento basal e aos 15 e 45 dias após a primeira aplicação da doxorrubicina. A atividade miocárdica dessas enzimas foi quantificada em apenas nove coelhos aos 45 dias e os resultados comparados com outros nove controles saudáveis. Foram identificadas apenas as formas inativas das MMPs 2 e 9 durante todo o estudo. A pro-MMP 2 plasmática reduziu à medida que a função cardiaca se deteriorou, enquanto a pro-MMP 9 aumentou significativamente em T45 quando comparada aos momentos basal e T15. Houve correlação negativa significativa entre a atividade plasmática da pro-MMP 2 e a relação entre E mitral e a velocidade anular mitral no início da diástole, um parâmetro que permite estimar a pressão atrial esquerda média e a congestão. Apenas a pro-MMP 2 foi documentada nas amostras miocárdicas dos coelhos com cardiomiopatia e atividade media dessa enzima foi estatisticamente menor que aquela observada nos controles saudáveis. Embora a forma ativa de ambas as colagenases não tenha sido identificada, o tempo de tratamento com doxorrubicina interferiu na atividade das formas inativas plasmáticas. Contudo, essas alterações não se associaram com a maioria dos parâmetros ecocardiográficos que indicam remodelamento cardíaco.(AU)
Assuntos
Animais , Coelhos , Doxorrubicina/toxicidade , Metaloproteinase 2 da Matriz/análise , Metaloproteinase 9 da Matriz/análise , Cardiomiopatias/veterinária , Colagenases , Ecocardiografia/veterináriaRESUMO
The aim of this study was to investigate the occurrence of Tritrichomonas foetus in cats in the area surrounding the city of Araçatuba municipality, State of São Paulo, Brazil. Fecal samples from 129 cats were collected by rectal flush technique. It was compared two diagnosis methods, direct examination of feces and PCR. The presence of T. foetus DNA was verified using PCR by amplification of 347-bp fragment from the primers TFR3 and TFR4 and amplicons of positive cases were sequenced. Statistical analyses were performed investigating the associations between T. foetus infection with gender, age, breed, presence of diarrhea and/or history of diarrhea, previous treatment, lifestyle, origin, environment, and co-infection. T. foetus was observed in one sample (n=129) by direct microscopic examination of feces while PCR was positive in five samples (3.9%). Giardia species and Cryptosporidium species co-infection was also observed. Statistical analyses showed no significant associations between T. foetus infection and all listed factors, although most positive cats were asymptomatic and lived in multi-cat household. The isolates of T. foetus showed 100% identical sequences with other T. foetus isolates from cats around the world. So, the occurrence of T. foetus was confirmed in cats in Araçatuba city (Brazil). This parasite must be considered as a differential diagnosis in cats with diarrhea and also in asymptomatic carriers as source of infection in multi-cat environments.(AU)
O objetivo deste estudo foi investigar a ocorrência de Tritrichomonas foetus em gatos na região do município de Araçatuba, SP, Brasil. Foram coletadas amostras fecais de 129 gatos através da técnica de lavado retal. Dois métodos diagnósticos foram comparados, o exame direto das fezes e a PCR. A presença de DNA de T. foetus foi verificada por meio da PCR através da amplificação de 347 pares de bases a partir dos iniciadores específicos TFR3 e TFR4. Posteriormente, os resultados amplificados das amostras positivas foram sequenciadas. Também foi feita análise estatística a fim de investigar a correlação entre infecção por T. foetus e sexo, idade, raça, presença e/ou histórico de diarreia, tratamento prévio, coinfecção, estilo de vida, origem e tipo de ambiente. O protozoário pôde ser observado em uma amostra através do exame direto das fezes e à PCR foram detectadas cinco amostras positivas (3.9%). Foram detectadas coinfecções por Giardia spp. e Cryptosporidium spp. Não foram observadas correlações entre infecção por T. foetus e todos os fatores listados anteriormente, embora a maioria dos felinos positivos fossem assintomáticos e vivessem em ambientes multigatos. O resultado do sequenciamento genético dos isolados das amostras positivas mostrou 100% de similaridade com outros isolados de felinos no mundo. Assim, a ocorrência de T. foetus foi confirmada em gatos em Araçatuba, São Paulo, Brasil. Sendo assim, o parasito deve considerado como diagnóstico diferencial em gatos com diarreia assim como em portadores assintomáticos como fontes de infecção em ambientes multigatos.(AU)
Assuntos
Animais , Gatos , Infecções por Protozoários/diagnóstico , Tritrichomonas foetus/isolamento & purificação , Doenças Parasitárias/diagnóstico , Brasil , Reação em Cadeia da Polimerase/veterinária , Diarreia/etiologiaRESUMO
ABSTRACT: Some studies have shown the role played by matrix metalloproteinases and their inhibitors in doxorubicin cardiotoxicity. In this study, we sought to investigate how plasma and myocardial MMP 2 and 9 perform in rabbits with doxorubicin-induced cardiomyopathy, searching for a correlation between the activity of these collagenases and cardiac remodeling. Cardiomyopathy was induced by doxorubicin given intravenously twice a week for six consecutive weeks. Plasma MMP activity and the echocardiogram were assessed at baseline, and at 15 and 45 days after first injection of doxorubicin. The myocardial activity of these enzymes was solely evaluated in nine rabbits at 45 days, and results were compared with nine healthy controls. We only identified the full-length forms of both MMP 2 and 9 throughout the study. The plasma pro-MMP 2 reduced along the deterioration of cardiac function, while the pro-MMP 9 increased significantly at T45 as compared to baseline and T15. A negative significant correlation was found to exist between the plasma activity of pro-MMP 2 and mitral E-to-mitral septal annular early diastolic velocity ratio, which is an estimate of mean left atrial pressure and congestion. Only pro-MMP 2 was found in myocardial samples, and mean activity of such enzyme was statistically lower than that recorded for healthy controls. Although no active form was documented for either collagenase, the duration of the treatment with doxorubicin played a role in the alteration of plasma pro-forms activity. However, these changes could not be associated with most echocardiographic parameters that are supportive of cardiac remodeling.
RESUMO: Alguns estudos já demonstraram o papel exercido pelas metaloproteinases de matriz e seus inibidores na cardiotoxicidade promovida pela doxorrubicina. Assim, este estudo teve como objetivo investigar o comportamento das MMPs 2 e 9 plasmáticas e miocárdicas em coelhos com cardiomiopatia induzida pela doxorrubicina, buscando determinar se há correlação entre a atividade dessas colagenases e o remodelamento cardíaco. A cardiomiopatia foi induzida pela doxorrubicina aplicada por via intravenosa duas vezes por semana ao longo de seis semanas consecutivas. A atividade plasmática das MMPs e o ecocardiograma foram avaliados no momento basal e aos 15 e 45 dias após a primeira aplicação da doxorrubicina. A atividade miocárdica dessas enzimas foi quantificada em apenas nove coelhos aos 45 dias e os resultados comparados com outros nove controles saudáveis. Foram identificadas apenas as formas inativas das MMPs 2 e 9 durante todo o estudo. A pro-MMP 2 plasmática reduziu à medida que a função cardiaca se deteriorou, enquanto a pro-MMP 9 aumentou significativamente em T45 quando comparada aos momentos basal e T15. Houve correlação negativa significativa entre a atividade plasmática da pro-MMP 2 e a relação entre E mitral e a velocidade anular mitral no início da diástole, um parâmetro que permite estimar a pressão atrial esquerda média e a congestão. Apenas a pro-MMP 2 foi documentada nas amostras miocárdicas dos coelhos com cardiomiopatia e atividade media dessa enzima foi estatisticamente menor que aquela observada nos controles saudáveis. Embora a forma ativa de ambas as colagenases não tenha sido identificada, o tempo de tratamento com doxorrubicina interferiu na atividade das formas inativas plasmáticas. Contudo, essas alterações não se associaram com a maioria dos parâmetros ecocardiográficos que indicam remodelamento cardíaco.
RESUMO
ABSTRACT: The aim of this study was to investigate the occurrence of Tritrichomonas foetus in cats in the area surrounding the city of Araçatuba municipality, State of São Paulo, Brazil. Fecal samples from 129 cats were collected by rectal flush technique. It was compared two diagnosis methods, direct examination of feces and PCR. The presence of T. foetus DNA was verified using PCR by amplification of 347-bp fragment from the primers TFR3 and TFR4 and amplicons of positive cases were sequenced. Statistical analyses were performed investigating the associations between T. foetus infection with gender, age, breed, presence of diarrhea and/or history of diarrhea, previous treatment, lifestyle, origin, environment, and co-infection. T. foetus was observed in one sample (n=129) by direct microscopic examination of feces while PCR was positive in five samples (3.9%). Giardia species and Cryptosporidium species co-infection was also observed. Statistical analyses showed no significant associations between T. foetus infection and all listed factors, although most positive cats were asymptomatic and lived in multi-cat household. The isolates of T. foetus showed 100% identical sequences with other T. foetus isolates from cats around the world. So, the occurrence of T. foetus was confirmed in cats in Araçatuba city (Brazil). This parasite must be considered as a differential diagnosis in cats with diarrhea and also in asymptomatic carriers as source of infection in multi-cat environments.
RESUMO: O objetivo deste estudo foi investigar a ocorrência de Tritrichomonas foetus em gatos na região do município de Araçatuba, SP, Brasil. Foram coletadas amostras fecais de 129 gatos através da técnica de lavado retal. Dois métodos diagnósticos foram comparados, o exame direto das fezes e a PCR. A presença de DNA de T. foetus foi verificada por meio da PCR através da amplificação de 347 pares de bases a partir dos iniciadores específicos TFR3 e TFR4. Posteriormente, os resultados amplificados das amostras positivas foram sequenciadas. Também foi feita análise estatística a fim de investigar a correlação entre infecção por T. foetus e sexo, idade, raça, presença e/ou histórico de diarreia, tratamento prévio, coinfecção, estilo de vida, origem e tipo de ambiente. O protozoário pôde ser observado em uma amostra através do exame direto das fezes e à PCR foram detectadas cinco amostras positivas (3.9%). Foram detectadas coinfecções por Giardia spp. e Cryptosporidium spp. Não foram observadas correlações entre infecção por T. foetus e todos os fatores listados anteriormente, embora a maioria dos felinos positivos fossem assintomáticos e vivessem em ambientes multigatos. O resultado do sequenciamento genético dos isolados das amostras positivas mostrou 100% de similaridade com outros isolados de felinos no mundo. Assim, a ocorrência de T. foetus foi confirmada em gatos em Araçatuba, São Paulo, Brasil. Sendo assim, o parasito deve considerado como diagnóstico diferencial em gatos com diarreia assim como em portadores assintomáticos como fontes de infecção em ambientes multigatos.
RESUMO
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.