Resumo

Canine rangeliosis is an extravascular hemolytic disease caused by the protozoan Rangelia vitalii, which is transmitted by ticks of the species Amblyomma aureolatum. The most common clinical signs are apathy, hyperthermia and spontaneous bleeding. Anemia and thrombocytopenia are the most common hematological findings. This work reports a clinical case of canine Rangeliosis treated at a private veterinary hospital, in São Paulo city in 2017. A dog was treated at a veterinary hospital in the north of São Paulo, with progressive weight loss, apathy and tail injury. Anemia and thrombocytopenia were observed on the hemogram. Rangelia vitalii DNA was detected in animal blood by real-time PCR (qPCR). In addition to the supportive treatment, doxycycline and subcutaneous imidocarb applications were used. The sample collected after treatment with the antibiotic continued to present protozoal DNA. The disease should be considered as a differential diagnosis and there is a great need for further studies about the therapy used.(AU)

A rangeliose canina é uma doença hemolítica extravascular causada pelo protozoário Rangelia vitalii, o qual é transmitido por carrapatos da espécie Amblyomma aureolatum. Os sinais clínicos mais comuns são apatia, hipertermia e sangramentos espontâneos. Os achados hematológicos mais comuns são anemia e trombocitopenia. Este trabalho teve como objetivo relatar um caso clínico de Rangeliose canina tratada em um hospital veterinário particular, na cidade de São Paulo no ano de 2017. Um cão foi atendido em um hospital veterinário da zona norte de São Paulo, com emagrecimento progressivo, apatia e lesão na cauda. No hemograma foram observadas anemia e trombocitopenia. Através da PCR em tempo real (qPCR) do sangue do animal constatou-se a presença de DNA de Rangelia vitalii. Além do tratamento de suporte, utilizou-se doxiciclina e aplicações subcutâneas de imidocarb. A amostra coletada após o tratamento com o antibiótico continuou apresentando DNA do protozoário. A enfermidade deve ser considerada como diagnóstico diferencial e há uma grande necessidade de maiores estudos acerca da terapia utilizada.(AU)

Resumo

Abstract Rangelia vitalii infects erythrocytes, leukocytes and endothelial cells of dogs. The present study aimed to report the molecular detection confirmed by sequencing of R. vitalii in the state of Paraná, as well as describe the clinical, hematological and biochemical alterations of the infected dogs. Three sick dogs from the metropolitan area of Curitiba, PR, Brazil, underwent a physical exam, and laboratory tests included hematology, biochemistry, polymerase chain reaction (PCR), and gene sequencing. Clinical signs included apathy, anorexia, and hemorrhage. Intra-erythrocytic and extracellular piroplasms were found on peripheral blood smears from all three dogs. Blood samples from these animals were positive for Babesia sp. by PCR targeting 18S rRNA. PCR products from all three dogs were sequenced, and BLAST analysis showed that the PCR-generated sequences were highly homologous with those of R. vitalii previously reported. Hematologic findings included severe anemia, shift of neutrophils to the regenerative left, and thrombocytopenia. Serum urea levels were increased in all three dogs, and direct bilirubin levels were elevated in one dog.

Resumo Rangelia vitalii infecta eritrócitos, leucócitos e células endoteliais de cães. O presente estudo objetivou relatar a detecção molecular confirmada por sequenciamento de R. vitalii no estado do Paraná e descrever as alterações clínicas, hematológicas e bioquímicas dos cães infectados. Três cães doentes da região metropolitana de Curitiba, PR, Brasil, foram submetidos a exame físico e exames laboratoriais que incluíram hematologia, bioquímica, reação em cadeia da polimerase (PCR) e sequenciamento genético. Os sinais clínicos incluíram apatia, anorexia e hemorragia. Piroplasmas intra-eritrocíticos e extracelulares foram encontrados em esfregaços de sangue periférico dos três cães. As amostras de sangue destes animais foram positivas para Babesia sp. pela PCR baseada no gene 18S rRNA. Os produtos de PCR dos três cães foram sequenciados e a análise de BLAST mostrou que as seqüências geradas por PCR eram altamente homólogas com as de R. vitalii previamente relatadas. Os achados hematológicos incluíram anemia grave, desvio de neutrófilos à esquerda regenerativo e trombocitopenia. Os níveis de uréia no soro aumentaram nos três cães, e os níveis de bilirrubina direta foram elevados em um cão.

Resumo

In the period from January 2004 to December 2015, 56 dogs were diagnosed with rangeliosis in the Setor de Patologia Veterinária at Universidade Federal do Rio Grande do Sul (SPV-UFRGS). The main hematological abnormalities were thrombocytopenia and anemia. The affected dogs showed signs of apathy, anorexia, fetid and bloody diarrhea, vomiting, and dehydration. At necropsy, the main changes were jaundice, splenomegaly, hepatomegaly, and lymphadenomegaly. Histological analyses revealed parasitophorous vacuoles of Rangelia vitalii in cytoplasmic endothelial cells, mainly in the heart, kidneys, lymph nodes, intestines, and pancreas. Inflammation characterized by mononuclear cells was predominant in the analysis, and most was due to the presence of plasma cells. Other lesion types observed were lymphoid hyperplasia, extramedullary hematopoiesis, erythrophagocytosis, and erythroid lineage hyperplasia in bone marrow. Of the total number of animals, 49 were diagnosed using necropsy and histological analysis, and seven were diagnosed using a molecular analysis (i.e., PCR and genetic sequencing of blood samples). This paper presented a different method of diagnosing rangeliosis in canines. This approach involved histological methods including the quantification and determination of the intensity and distribution of the infectious agent in different organs.

No período de janeiro de 2004 a dezembro de 2015, 56 caninos domésticos obtiveram o diagnóstico de rangeliose no Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (UFRGS). Os cães apresentaram sinais de apatia, anorexia, diarreia fétida e sanguinolenta, êmese e desidratação. As principais alterações hematológicas foram trombocitopenia e anemia. Na necropsia as principais alterações foram icterícia, esplenomegalia, hepatomegalia e linfadenomegalia. Na análise histológica observou-se vacúolos parasitóforos de Rangelia vitalii no citoplasma de células endoteliais, principalmente no coração, rins, linfonodos, intestinos e pâncreas. A inflamação mononuclear foi predominante na análise, sendo que a maioria deu-se pela presença de plasmócitos. Entre outras lesões frequentemente observadas estão hiperplasia linfoide, hematopoiese extramedular e eritrofagocitose, e hiperplasia de linhagem eritroide em medula óssea. Do total, 49 cães foram diagnosticados através de necropsia e análise histológica, e 7 animais através de análise molecular da PCR e sequenciamento genético de amostras de sangue. Este trabalho apresenta um diagnóstico diferencial de rangeliose em caninos, através do método histológico de quantificação e determinação de intensidade e distribuição do agente em diferentes órgãos.

Resumo

Abstract Rangelia vitalii infects erythrocytes, leukocytes and endothelial cells of dogs. The present study aimed to report the molecular detection confirmed by sequencing of R. vitalii in the state of Paraná, as well as describe the clinical, hematological and biochemical alterations of the infected dogs. Three sick dogs from the metropolitan area of Curitiba, PR, Brazil, underwent a physical exam, and laboratory tests included hematology, biochemistry, polymerase chain reaction (PCR), and gene sequencing. Clinical signs included apathy, anorexia, and hemorrhage. Intra-erythrocytic and extracellular piroplasms were found on peripheral blood smears from all three dogs. Blood samples from these animals were positive for Babesia sp. by PCR targeting 18S rRNA. PCR products from all three dogs were sequenced, and BLAST analysis showed that the PCR-generated sequences were highly homologous with those of R. vitalii previously reported. Hematologic findings included severe anemia, shift of neutrophils to the regenerative left, and thrombocytopenia. Serum urea levels were increased in all three dogs, and direct bilirubin levels were elevated in one dog.

Resumo Rangelia vitalii infecta eritrócitos, leucócitos e células endoteliais de cães. O presente estudo objetivou relatar a detecção molecular confirmada por sequenciamento de R. vitalii no estado do Paraná e descrever as alterações clínicas, hematológicas e bioquímicas dos cães infectados. Três cães doentes da região metropolitana de Curitiba, PR, Brasil, foram submetidos a exame físico e exames laboratoriais que incluíram hematologia, bioquímica, reação em cadeia da polimerase (PCR) e sequenciamento genético. Os sinais clínicos incluíram apatia, anorexia e hemorragia. Piroplasmas intra-eritrocíticos e extracelulares foram encontrados em esfregaços de sangue periférico dos três cães. As amostras de sangue destes animais foram positivas para Babesia sp. pela PCR baseada no gene 18S rRNA. Os produtos de PCR dos três cães foram sequenciados e a análise de BLAST mostrou que as seqüências geradas por PCR eram altamente homólogas com as de R. vitalii previamente relatadas. Os achados hematológicos incluíram anemia grave, desvio de neutrófilos à esquerda regenerativo e trombocitopenia. Os níveis de uréia no soro aumentaram nos três cães, e os níveis de bilirrubina direta foram elevados em um cão.

Resumo

Background: The cholinergic system is involved in many biological functions in mammals and is associated with pathogenesis of infectious diseases, as has participation in transmission of nerve impulses in cholinergic synapses, haematopoiesis, regulation of inflammatory markers, production and coordination of movement, and memory. Rangelia vitalii is a parasite endemic to south of Brazil. This parasite multiplies in the blood and can be visualized in plasma in its free form and/or within leukocytes and erythrocytes, causing various pathologies. Therefore, the purpose of this study was to investigate the activity of cholinergic system enzymes in dogs experimentally infected with R. vitalii. Materials, Methods & Results: Twelve dogs were used, divided into two groups: control group (n = 5), consisting of healthy animals, and infected group with R. vitalii (n = 7). Fresh blood samples of these infected animals were inoculated in seven dogs (2 mL/dog through the jugular vein). Blood samples were collected on days 0, 10 and 20 post-infection (PI). Butyrylcholinesterase (BChE) activity was measured in serum and acetylcholinesterase (AChE) in lymphocytes and whole blood. Boold samples were diluted 1:50 (v/v) in lysis solution (0.1 mmol/L potassium/sodium phosphate buffer containing 0.03% Triton X-100) and frozen (-20 ºC by 7 days) to determine AChE activity in whole blood. Lymphocytes were also obtained from whole blood with EDTA by gradient separation using Ficoll-Histopaque™ plus to AChE activity this cell. After analysis of the samples, was observed that the dogs infected with R. vitalii presented a signifi cant (P < 0.01) increase in AChE activity in whole blood on days 10 and 20 PI. However, the infected group showed a reduced activity in AChE in lymphocytes (P < 0.01) and BChE in serum (P < 0.05) on day 20 PI. Discussion: According to the literature, infected dogs R. vitalii develop regenerative anemia evidenced by an increase in the erytroid precursors in bone marrow associated with alterations of leucogram as leukopenia, neutropenia, eosinopenia, lymphocytosis and monocytosis. Furthermore, it was observed severe thrombocytopenia, with alteration in platelet aggregation and activity of enzymes involved in the control of ATP, ADP and adenosine levels on platelets, thereby influencing hemostasis and contributing to the typical bleeding disease. AChE activity in whole blood was increased in dogs parasitized by R. vitalii observed in this study. This increase may be a compensatory effect to severe anemia caused by the parasite infection, because this enzyme is involved in the maturation of erythrocytes and in the regulation of hematopoiesis. In the present study, we found that the reduction in AChE activity in lymphocytes is associated to lymphocytosis; and it is known that ACh is produced within lymphocytes and has the ability to negatively modulate the immune response, acting directly on the inhibition of inflammatory mediators. Therefore, the decrease of AChE activity may have an anti-inflammatory action in order to have more free ACh to bind lymphocytes and inhibit inflammation. The enzyme BChE can also act as an inflammatory marker in various diseases, similar to AChE, because the enzyme can hydrolyze acetylcholine when AChE is inhibited. In conclusion, our results indicate that canine rangeliosis alters the activity of cholinesterase's, which may be involved in the pathogenesis of the disease, as well as various pathological conditions.

Resumo

Background: The cholinergic system is involved in many biological functions in mammals and is associated with pathogenesis of infectious diseases, as has participation in transmission of nerve impulses in cholinergic synapses, haematopoiesis, regulation of inflammatory markers, production and coordination of movement, and memory. Rangelia vitalii is a parasite endemic to south of Brazil. This parasite multiplies in the blood and can be visualized in plasma in its free form and/or within leukocytes and erythrocytes, causing various pathologies. Therefore, the purpose of this study was to investigate the activity of cholinergic system enzymes in dogs experimentally infected with R. vitalii. Materials, Methods & Results: Twelve dogs were used, divided into two groups: control group (n = 5), consisting of healthy animals, and infected group with R. vitalii (n = 7). Fresh blood samples of these infected animals were inoculated in seven dogs (2 mL/dog through the jugular vein). Blood samples were collected on days 0, 10 and 20 post-infection (PI). Butyrylcholinesterase (BChE) activity was measured in serum and acetylcholinesterase (AChE) in lymphocytes and whole blood. Boold samples were diluted 1:50 (v/v) in lysis solution (0.1 mmol/L potassium/sodium phosphate buffer containing 0.03% Triton X-100) and frozen (-20 ºC by 7 days) to determine AChE activity in whole blood. Lymphocy

Background: The cholinergic system is involved in many biological functions in mammals and is associated with pathogenesis of infectious diseases, as has participation in transmission of nerve impulses in cholinergic synapses, haematopoiesis, regulation of inflammatory markers, production and coordination of movement, and memory. Rangelia vitalii is a parasite endemic to south of Brazil. This parasite multiplies in the blood and can be visualized in plasma in its free form and/or within leukocytes and erythrocytes, causing various pathologies. Therefore, the purpose of this study was to investigate the activity of cholinergic system enzymes in dogs experimentally infected with R. vitalii. Materials, Methods & Results: Twelve dogs were used, divided into two groups: control group (n = 5), consisting of healthy animals, and infected group with R. vitalii (n = 7). Fresh blood samples of these infected animals were inoculated in seven dogs (2 mL/dog through the jugular vein). Blood samples were collected on days 0, 10 and 20 post-infection (PI). Butyrylcholinesterase (BChE) activity was measured in serum and acetylcholinesterase (AChE) in lymphocytes and whole blood. Boold samples were diluted 1:50 (v/v) in lysis solution (0.1 mmol/L potassium/sodium phosphate buffer containing 0.03% Triton X-100) and frozen (-20 ºC by 7 days) to determine AChE activity in whole blood. Lymphocy

Resumo

Os processos de fragmentação florestal e de perda de hábitats representam um dos principais riscos à biodiversidade, pois transformam os ecossistemas de forma rápida e artificial levando a alteração dos processos ecológicos naturais. Essas perturbações ecológicas podem alterar os complexos hospedeiros-vetores criando novos padrões de transmissão das doenças. Entre estes agentes, podemos destacar Rangelia vitalii, um protozoário emergente transmitido pelo carrapato Amblyomma aureolatum, que causa uma severa doença em cães domésticos (chamada rangeliose) na América do Sul e que tem sido recentemente também detectado em canídeos silvestres, principalmente em avaliações post-mortem. Este estudo propõe a investigação da circulação de protozoários da ordem Piroplasmida em populações de canídeos silvestres de vida livre do Estado do Rio Grande do Sul, através do uso de técnicas de diagnóstico molecular. Entre os meses de dezembro de 2014 e dezembro de 2016, foram capturados 27 espécimes de Cerdocyon thous e seis espécimes de Lycalopex gymnocercus em quatro diferentes áreas do Bioma Pampa. Dos canídeos capturados foram colhidas amostras de sangue para análise hematológica e testes por PCR. Dos 33 animais capturados 30 estavam parasitados por ectoparasitas, e aproximadamente 80% dos carrapatos identificados eram da espécie Amblyomma aureolatum. Oito amostras sanguíneas foram positivas para presença de DNA de Piroplasmida. Todas as amostras positivas foram sequenciadas, sendo que o sequenciamento confirmou presença de DNA de Rangelia vitalii. No entanto, a avaliação clínica dos graxains confirmou que estes não apresentavam sinais clínicos compatíveis com a apresentação clínica de rangeliose. A análise hematológica demonstrou que não houve alterações significativas entre os canídeos infectados e não infectados. Esses dados corroboram a hipótese da existência de um ciclo natural envolvendo canídeos silvestres, neste caso, C. thous e R. vitalii. Ao contrário do que ocorre em cães domésticos, nos quais a infecção por R. vitalii induz uma severa doença, em canídeos silvestres, na ausência de condições estressoras, parece apresentar-se de forma assintomática. Estes resultados tem particular importância nas decisões de órgãos ambientais relacionadas à destinação de fauna silvestre, nas quais a presença/ausência de determinados agentes ou parasitas determina soltura, reabilitação ou manutenção em cativeiro. A pesquisa da distribuição de parasitos entre diferentes espécies e populações, é uma ferramenta para investigar a troca de agentes entre espécies domésticas e silvestres e como o meio pode influenciar nesse processo reforçando a indissociabilidade entre a tríade agente etiológico-hospedeiro-ambiente.

The processes of forest fragmentation and habitat loss represent one of the main risks to biodiversity, as they transform ecosystems quickly and artificially, leading to the alteration of natural ecological processes. These ecological disturbances can alter the host-vector complexes creating new patterns of disease transmission. In this sense, Rangelia vitalii is an emergent tick-borne protozoan (transmitted by Amblyomma aureolatum ticks) that causes a severe disease (called rangeliosis) in domestic dogs in South America which, recently, has been also detected in wild canids by post-mortem analysis. This study aimed to evaluate the circulation of Piroplasmida protozoan in free-ranging wild canids from Rio Grande do Sul state, through the use of molecular diagnostic techniques. Between December 2014 and December 2016, 27 specimens of Cerdocyon thous and six specimens of Lycalopex gymnocercus were live-trapped in four different areas of the Pampa Biome. Blood samples were collected from the sampled canids for haematological analysis and PCR tests. From the 33 captured animals, 30 were parasitized by ectoparasites, and approximately 80% of the ticks were Amblyomma aureolatum. Eight canid samples were positive for the presence of Piroplasmida DNA. All positive samples were sequenced, which confirmed the presence of Rangelia vitalii DNA. On the other hand, none of the sampled canids showed clinical findings compatible with the clinical presentation of rangeliosis. Hematological analysis demonstrated that there are no significant changes between infected and uninfected C. thous. The set of results presented here support the hypothesis of a natural cycle of R. vitalii in C. thous. Contrarly to the observed for domestic dogs, it seems that, in the absence of stressor conditions, infection by R. vitalii in neotropical wild canids may be asymptomatic. These findings may have great impact in the wildlife management, since the presence/absence of certain parasites or microorganisms determines if animals would be destined to release into the wild, rehabilitation or captivity. The research on the distribution of parasites among different species and populations is a tool to investigate the exchange of agents between domestic and wild species and how the environment can influence this process by reinforcing the inseparability between the triad etiologic agent-host-environment.

Resumo

Rangelia vitalii is a protozoon that causes diseases in dogs, and anemia is the most common laboratory finding. However, few studies on the biochemical changes in dogs infected with this protozoon exist. Thus, this study aimed to investigate the biochemical changes in dogs experimentally infected with R. vitalii, during the acute phase of the infection. For this study, 12 female dogs (aged 6-12 months and weighing between 4 and 7 kg) were used, divided in two groups. Group A was composed of healthy dogs (n = 5); and group B consisted of infected animals (n = 7). Blood samples were collected on days 0, 10, 20 and 30 after infection, using tubes without anticoagulant to obtain serum and analyze the biochemical parameters. An increase in alanine aminotransferase (ALT) on day 20 (P < 0.05) was observed. Also, increased creatine kinase (CK) and aspartate aminotransferase (AST) levels were observed throughout the experimental period (P < 0.05). No changes in the serum gamma-glutamyltransferase, urea and creatinine levels were observed. Thus, is possible to conclude that experimental infection with R. vitalii in dogs causes changes to the biochemical profile, with increased ALT, AST and CK enzyme levels.

Rangelia vitalii é um protozoário que causa doença em cães, sendo a anemia o achado laboratorial mais frequente. No entanto, existem poucos estudos sobre as alterações bioquímicas em cães infectados com o protozoário. Assim, este estudo tem como objetivo investigar as alterações bioquímicas de cães experimentalmente infectados com R. vitalii na fase aguda da infecção. Para o estudo, foram utilizados 12 cães fêmeas (com idade entre 6 a 12 meses e peso entre 4 a 7 kg), divididos em dois grupos. O grupo A (n = 5) foi composto de animais saudáveis e o grupo B (n = 7) de animais infectados. Amostras de sangue foram coletadas nos dias zero, dez, vinte e trinta PI, utilizando tubos sem anticoagulante para obtenção de soro e análise dos parâmetros bioquímicos. Foi observado um aumento na alanino aminotransferase (ALT) no dia 20 PI (P < 0,05) e aumento na creatinoquinase (CK) e aspartato aminotransferase (AST) em todo o período experimental (P < 0,05). Não foram observadas alterações séricas na gama-glutamiltransferase, uréia e creatinina. Portanto, é possível concluir que a infecção experimental por R. vitalii causa alterações no perfil bioquímico, com aumento na ALT, CK e AST.

Resumo

Rangelia vitalii é um piroplasma que esta relacionada ao gênero Babesia, pertencente ao Filo Apicomplexa, Classe Sporozoasida, Ordem Piroplasmorida, que causa, em cães, uma doença conhecida como rangeliose desde o início do século XX, caracterizada por um distúrbio hemolítico e hemorrágico. O objetivo deste trabalho consiste na caracterização epidemiológica, análise dos achados macroscópicos, microscópicos e hematológicos, além da detecção molecular e sequenciamento genético de casos de rangeliose canina em canídeos diagnosticados no Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul. Foram avaliados 55 caninos com diagnóstico de rangeliose de janeiro de 2004 a dezembro de 2015. Desses, 49 foram diagnosticados através de necropsia e análise histológica, e 7 casos através de análise molecular da PCR e sequenciamento genético por amostra de sangue. As principais lesões macroscópicas observadas eram caracterizadas por mucosas ictéricas, esplenomegalia, hepatomegalia, linfadenomegalia e em alguns casos aumento das tonsilas. Diversos graus de hemorragia foram observados na mucosa do estômago, intestino delgado, intestino grosso, rins, pulmões e coração. Na análise histológica havia estruturas compatíveis com o piroplasma R. vitalii no citoplasma de células endoteliais de capilares sanguíneos, principalmente no coração, pulmões, rins, intestino delgado, linfonodos, baço e pâncreas. A inflamação de característica mononuclear foi predominante na avaliação dos órgãos, sendo que a maioria se deu pela presença de plasmócitos, e os principais órgãos afetados foram rins, estômago, coração e pulmões. As principais lesões hepáticas foram, inflamação mononuclear, colestase, eritrofagocitose, necrose paracentral e hematopoiese extramedular. No baço da maioria dos cães foi visualizada hematopoiese extramedular e eritrofagocitose, e nos linfonodos havia rarefação linfoide e eritrofagocitose. Na medula óssea, hiperplasia de linhagem eritroide foi a lesão mais observada. Outro objetivo é relatar o diagnóstico desta piroplasmose em dois canídeos selvagens, um graxaim-do-mato (Cerdocyon thous) e um graxaim-do-campo (Lycalopex gymnocercus). No exame macroscópico, ambos apresentaram mucosas pálidas, esplenomegalia, discreta linfadenomegalia e o padrão hepático evidente. As estruturas compatíveis com R. vitalii foram observados no citoplasma de células endoteliais do fígado, estômago, coração, rim, pulmões, gânglios linfáticos, e da bexiga. O agente foi caracterizado por PCR e sequenciamento genético através de amostras de fígado e carrapatos.

Rangelia vitalii is a piroplasma of the Babesia genus that belongs to Apicomplexa phylum, Sporozoasida class, and Piroplasmorida order, that causes in dogs a disease, characterized by hemolytic and hemorrhagic disorder, known as rangeliosis since the early twentieth century. The aim of this work is to describe the epidemiological characterization, analyze pathological and hematological findings, in addition to molecular detection and genetic sequencing of cases of rangeliosis in canines diagnosed in the Sector of Veterinary Pathology of the Federal University of Rio Grande do Sul. We evaluated 55 dogs diagnosed with rangeliosis between January 2004 to December 2015. Of these, 49 were diagnosed through necropsy and histological analysis, and 7 cases through molecular analysis by PCR and genetic sequencing of blood sample. The main gross lesions were characterized by generalized jaundiced, splenomegaly, hepatomegaly, lymphadenopathy, and in some cases enlarged tonsils. Various degrees of hemorrhage were observed in the mucosa of stomach, small intestine, large intestine, kidneys, lungs, and heart. Histological analysis was compatible with R. vitalii within the cytoplasm of endothelial cells of blood capillaries, especially in the heart, lungs, kidneys, small intestine, lymph nodes, spleen, and pancreas. Inflammation was predominantly mononuclear, most of which was characterized by the presence of plasma cells, and the main affected organs were kidney, stomach, heart, and lungs. The major hepatic lesions were mononuclear inflammation, cholestasis, erythrophagocytosis, paracentral necrosis, and extramedullary hematopoiesis. In spleen of most dogs was observed extramedullary hematopoiesis and erythrophagocytosis, and in lymph nodes were observed lymphoid rarefaction and erythrophagocytosis. In the bone marrow, erythroid lineage hyperplasia was the most commonly observed alteration. By analyzing the hematological findings of 17 dogs, it was noted that all patients had thrombocytopenia, and 15 animals had hypochromic macrocytic anemia. Another objective is to report the diagnosis of rangeliosis in two wild canids, a crab-eating fox (Cerdocyon thous) and a Pampas fox (Lycalopex gymnocercus). On gross examination, both had paleness, slight splenomegaly and lymphadenopathy, and noticeable acinar pattern. The structures compatible with R. Vitalii were observed in the cytoplasm of endothelial cells of liver, stomach, heart, kidney, lungs, lymph glands, and bladder. The agent was characterized by PCR and genetic sequencing of liver and tick samples.

Resumo

A patogênese e os achados clínicos, hematológicos e anatomopatológicos da infecção natural pelo protozoário Rangelia vitalii (rangeliose canina) foram estudados em 35 cães que morreram em consequência dessa condição. Os resultados obtidos permitem o seguinte conjunto de conclusões: (1) causa doença hemolítica exclusivamente extravascular e de origem imunomediada; (2) cursa invariavelmente com algum grau de hemorragia à necropsia, mas nem sempre clinicamente perceptível; (3) os principais sinais que devem chamar a atenção para a suspeita clínica são anemia, icterícia e esplenomegalia; (4) o principal achado hematológico e que deve chamar a atenção para a suspeita clínica é a ocorrência de anemia com sinais de intensa regeneração eritroide; (5) os três principais diagnósticos diferenciais são leptospirose, babesiose e erliquiose monocitotrópica aguda; (6) a principal lesão observada é uma associação de hiperplasia linfoide com inflamação mononuclear, predominantemente plasmocitária, mas por vezes granulomatosa; (7) outras lesões frequentes são secundárias à marcada anemia regenerativa; (8) o agente etiológico pode ser facilmente encontrado, pois ocorre em grande quantidade na maioria dos tecidos, principalmente nos linfonodos, no baço, na medula óssea, no coração e nas tonsilas.

The pathogenesis, clinical, hematological and pathological features of the natural infection by the protozoan organism Rangelia vitalii (canine rangeliosis) was studied in 35 dogs that died due this condition. The results allow for the following set of conclusions on canine rangeliosis: (1) causes an exclusively extravascular immune mediated hemolysis; (2) is invariably associated with some degree of hemorrhage observed at necropsy, but no always clinically apparent; (3) the clinical signs that are the hallmark of the disease are anemia, icterus and splenomegaly; (4) the main hematological aspect that establishes a clinical suspect is the development of anemia with signs of intense erythroid regeneration; (5) the three main differential diagnosis are leptospirosis, babesiosis and e acute monocytotropic ehrlichiosis; (6) the main observed histopathological lesion is an association of lymphoid hyperplasia with mononuclear inflammatory reaction, predominantly plasmacytic, but occasionally granulomatous; (7) other frequently found lesions are secondary to a marked regenerative anemia; (8) large numbers of the etiologic agent can be easily demonstrate in most tissues, mainly in lymph nodes, spleen, bone marrow, heart, and tonsils.