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Rangelia vitalii is a protozoan of the Babesiidae family that parasitizes domestic and wild dogs in South American countries. The main laboratory findings in blood samples from animals infected by R. vitalii are anemia and thrombocytopenia. The aim of this study was to detect IgM and IgG immunoglobulins on the surface of red blood cells and platelets, as well as to determine the percentage of reticulated platelets and reticulocytes in dogs naturally infected by R. vitalii. Blood samples from twenty dogs seen at the Veterinary Hospital of the Federal University of Santa Maria (UFSM) were divided into two groups: the diseased group consisted of blood samples from 10 animals with the diagnosis of rangeliosis, and the healthy group (control) consisted of samples from 10 healthy animals. All diseased dogs showed normocytic normochromic anemia but showed no differences (p > 0.05) in reticulocyte counts compared to healthy dogs. Moreover, IgM and IgG immunoglobulins were detected on the surface of the plasma membrane of red blood cells from both groups, but the amounts did not differ between groups (p > 0.05). Thrombocytopenia in infected animals was classified as severe. The percentage of reticulated platelets was higher (p < 0.001) in diseased dogs than in healthy animals. Diseased animals showed more IgM immunoglobulins bound to the surface of platelets than did the healthy group (p < 0.001). However, the amount of IgG bound to the surface of platelets was not different between groups. In conclusion, we showed that R. vitalii caused immune-mediated thrombocytopenia since IgM immunoglobulins were found on the surface of platelets of diseased dogs. We suggest that the binding of immunoglobulins on platelet surfaces contributes to early destruction of these cells and, consequently, alterations in hemostasis. An increase in reticulated platelets was noted in response to thrombocytopenia, indicating active thrombopoiesis., (Copyright © 2018. Published by Elsevier Ltd.)

Rangelia vitalii is the etiologic agent of canine rangeliosis, a severe piroplasmosis that affects domestic dogs in Brazil, Uruguay and Argentina. While R. vitalii is one of the most pathogenic tick-borne pathogens for dogs in the world, its tick vector has remained unknown. The present study evaluated the vector competence of Rhipicephalus sanguineus sensu lato (both tropical and temperate species), Amblyomma aureolatum, Amblyomma ovale, Amblyomma tigrinum, and Amblyomma sculptum for R. vitalii. These six tick species were selected for the study because they comprise the main tick species infesting dogs within the distribution area of canine rangeliosis in South America. Acquisition feeding of the above six tick species was performed on domestic dogs showing clinical signs of canine rangeliosis, after being experimentally infected through intravenous inoculation or infestation with R. vitalii-infected ticks. Thereafter, engorged ticks were evaluated for transstadial and transovarial passages of R. vitalii through molecular analysis after molting or oviposition and egg hatching. The resultant ticks were evaluated for their competence to transmit R. vitalii to susceptible dogs. Among the six tick species, only A. aureolatum was able to acquire and perpetuate R. vitalii by transstadial and transovarial passages, as demonstrated by >5% infection rates of ticks after hatching or molting. When exposed to transmission feeding, only A. aureolatum ticks were competent to transmit R. vitalii to dogs, which became severely ill, and the results confirmed by molecular methods and blood smear examination to have acquired rangeliosis. Results of the present study, coupled with epidemiological data, indicate that A. aureolatum is a natural vector of R. vitalii. Our results also indicate that R. vitalii is the first Piroplasmorida agent to be transovarially transmitted in Amblyomma ticks., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Canine rangeliosis (popular names: "nambi-uvú", i.e. ``bleeding ears''; "peste de sangue", i.e. ``bleeding plague''; and "febre amarela dos cães", i.e. ``yellow fever of dogs'') is a tick-borne haemolytic and haemorrhagic disease caused by the protozoan parasite Rangelia vitalii which infects erythrocytes, leukocytes, and endothelial cells of blood capillaries. Rangelia vitalii was first reported as a novel piroplasm of dogs in 1910 in Brazil, a discovery that was met with skepticism at that time. Canine rangeliosis has been diagnosed in domestic dogs not only in Brazil but also in other South American countries (Argentina and Uruguay). Rangelia vitalii infection has also been found incidentally in Brazil in wild dogs (Cerdocyon thous, the crab-eating fox). Despite the fact that researchers in the early 1900s suggested that R. vitalii was a hitherto unidentified piroplasm that would be transmitted by the tick Amblyomma aureolatum, it was not until 2012 that these hypotheses were actually confirmed by PCR and transmission studies. Molecular studies have shown that R. vitalii is related to the Babesia sensu strictu clade, but genetically different from other morphologically similar species of Babesia that infect dogs. Another difference between Babesia spp. and R. vitalii is the ability of R. vitalii to invade endothelial cells, erythrocytes, and leukocytes. Experimental infection in dogs has successfully reproduced the clinical picture and pathology of the natural disease. In this article, epidemiology, clinical signs, laboratory findings, pathogenetic mechanisms including oxidative stress and immune response, necropsy findings, microscopic lesions, diagnosis, and treatment of canine rangeliosis are reviewed. What is currently known about this protozoal disease since its first report over a century ago is presented herein., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Ecto-adenosinedeaminase (E-ADA) plays an important role in the production and differentiation of blood cells as well as in the control of extracellular adenosine levels. Infectious diseases can influence the synthesis of new cells or cause cell destruction, as occurs in canine rangeliosis, which results in anemia, thrombocytopenia, leukocytosis, and/or leukopenia. Thus, this study aimed to evaluate E-ADA activity in sera, erythrocytes, lymphocytes, and adenosine levels in sera samples of dogs infected by Rangelia vitalii. Twelve animals were divided into 2 groups: noninfected (n = 5) and infected by R. vitalii (n = 7). Animals were infected with 2 ml of blood containing the parasite, and parasitemia was estimated daily for 20 days by microscopic examination of peripheral blood smears. Blood collection was performed on days 0, 10, and 20 post-infection (PI) in order to evaluate the evolution of the disease. The blood collected was used to assess the activity of E-ADA. We observed an increase of E-ADA activity in sera (day 20 PI) and erythrocytes (days 10 and 20 PI) in the infected group (P < 0.05). E-ADA activity in lymphocytes was decreased on day 10, when the parasitemia was high, and increased after 20 days, when the number of circulating parasites was low. HPLC measured adenosine levels in the serum and found a reduction on days 10 and 20 PI. In conclusion, our results showed that E-ADA activity was altered in sera, lymphocytes, and erythrocytes of dogs experimentally infected by R. vitalii as well as the serum concentration of adenosine. These alterations may contribute to the pathogenesis of anemia and immune response in infected dogs.

Background: Rangelia vitalii is a tick-transmitted piroplasm that causes both hemolytic and hemorrhagic disease in dogs in Brazil., Objective: The aim of this study was to evaluate the response of the bone marrow in dogs experimentally infected with R vitalii during the acute stage of the disease., Methods: For this study, 2 groups of a total of 12 young dogs were used. Group A was composed of healthy dogs (n = 5), and group B consisted of animals infected with R vitalii (n = 7). Blood samples were collected on days 0, 10, 20, and 30 post-inoculation and stored in EDTA tubes for a full hematology profile, including a reticulocyte count. On days 10 and 20, bone marrow samples were collected, stained, and examined., Results: In infected dogs anemia was identified on days 10 and 20 post-inoculation (P < .01), and on day 20 reticulocytosis was present. Infected dogs had leukopenia due to neutropenia and eosinopenia, along with lymphocytosis and monocytosis, when compared with control animals. In bone marrow, the myeloid:erythroid ratio was significantly decreased (P < .05) in infected dogs due to increased erythroid precursors., Conclusions: Dogs experimentally infected with R vitalii develop regenerative extravascular hemolytic anemia accompanied by erythroid hyperplasia in the bone marrow. During the acute phase of the disease, leukopenia due to neutropenia and eosinopenia suggests intense tissue recruitment of these cells in response to the endothelial damage caused by this parasite., (© 2013 American Society for Veterinary Clinical Pathology.)

Rangeliosis is a hemoparasitosis that affects dogs in Brazil. The disease has similar clinical and pathological characteristics to other hemo-protozoan infections. So, this paper has aimed to report a clinical case of infection by Rangelia vitalii in one dog, focusing on the need for the differential diagnosis to other infectious diseases. The animal showed apathy, anemia, thrombocytopenia, alteration of leucogram, and bleeding. The first difference was the observation of parasites in blood smears, where R. vitalii was visualized within leukocytes and erythrocytes. The confirmation of the clinical diagnosis was made by molecular test to R. vitalii. The dog was debilitated, and died a few hours after treatment at the veterinary hospital. At necropsy, splenomegaly, lymphadenopathy, and mild jaundice in the abdominal viscera were found. This article draws attention to the need for the parasitological, serological, and molecular to differential diagnosis in order to differentiate from other clinically similar disorders.

The present study aimed to evaluate the serum proteinogram, acute phase proteins (APPs) and immunoglobulins (Igs) of dogs experimentally infected by Rangelia vitalii in the acute phases of the disease. Banked serum samples collected on days 0, 10 and 20 during a previously reported R. vitalii experimental infection were used to analyze the serum proteinogram, APPs (C-reactive protein - CRP and alpha-1-acid glycoprotein - AGP) and Igs (IgM, IgG, IgA and IgE) in the current study. Total protein and albumin level were significantly (P<0.05) decreased at day 10 PI and 20 PI in infected sera compared to the control sera. Alpha-1 globulin (day 10 PI) and gamma globulin (day 20 PI) were increased (P<0.01) in infected sera. Alpha-2 globulin (days 10 and 20 PI) and beta-2 globulin (day 10 PI) were decreased (P<0.05) in infected sera compared to control sera. Beta-1 globulin fraction did not differ statistically between sera. Serum CRP and AGP concentrations were significantly increased (P<0.05) at days 10 and 20 PI in infected sera. IgG was increased at days 10 (P<0.05) and 20 PI (P<0.01) in infected sera. Furthermore, it was also observed an increase (P<0.01) in the levels of IgM, IgA, and IgE in infected sera than control sera. We conclude that R. vitalii infection causes alterations in the proteinogram, and increases in the levels of APPs and Igs. Further studies are essentials to define the causes of these pathological changes in this disease., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The aim of this study was to evaluate lipid peroxidation, protein oxidation and activity of enzymes that are indicators of oxidative stress in Rangelia vitalii infection in dogs. Animals were divided into two groups: negative control (n=5) and infected with R. vitalii (n=7). After inoculation, the parasitemia was estimated daily by microscopic examination of smears. Lipid peroxidation (TBARS) and advanced oxidation protein products (AOPP); and delta-aminolevulinate dehydratase (δ-ALA-D), superoxide dismutase (SOD) and catalase (CAT) activities in blood were evaluated. The samples were collected at days 10 and 20 post-inoculation (PI). TBARS and AOPP levels were higher in the infected group in both analyzed periods (P<0.01). The δ-ALA-D activity was reduced in blood of dogs infected with R. vitalii on days 10 and 20 PI. SOD activity was significantly increased (P<0.01) in the blood of dogs infected with R. vitalii at days 10 and 20 PI, while CAT activity was significantly increased (P<0.01) only at day 20 PI when compared to non-infected animals. A positive correlation was observed between the degree of parasitemia and TBARS and AOPP levels and activity of antioxidant enzymes. The δ-ALA-D activity was negatively correlated with the degree of parasitemia. Based on the increased levels of TBARS, AOPP, SOD and CAT activities, and inhibition δ-ALA-D activity, we concluded that dogs experimentally infected with R. vitalii develop a state of redox unbalance and that these changes might be involved in the pathophysiology of disease., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The aim of this study was to evaluate the concentrations of copper, iron, and zinc in blood serum of dogs experimentally infected with Rangelia vitalii (n  =  7) compared with uninfected controls (n  =  5). Serum metal levels were determined in blood samples collected at days 0, 10, 15, and 20 post-infection (PI). Inductively coupled plasma optical emission spectrometry was used to measure the levels of copper, iron, and zinc. Significant differences (P < 0.05) were observed among groups PI. Increased levels of copper and decreased levels of iron and zinc were observed in the infected animals. The infection by R. vitalii may, therefore, alter the serum metal levels, resulting in metabolic disorders in dogs. These metals are directly involved in many enzymatic systems; accordingly, alterations in their blood concentrations may also influence the pathogenesis of disease.

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.

Rangeliosis is a disease which affects dogs in Brazil, caused by a piroplasm known as Rangelia vitalii. This disease causes a lot of clinico-pathological features, including the coagulation disorders associated with bleeding. The cause of these changes has not yet been determined. Considering the association of purinergic system and hemostasis this study aimed to evaluate the activity of enzymes that hydrolyze ATP, ADP and AMP; and deamination of adenosine in platelets from dogs experimentally infected with R. vitalii. For this study, 12 healthy young dogs (females) were used, separated in two groups. Group A (n=5) were uninfected controls, and group B were experimentally infected with R. vitalii (n=7). After being inoculated with R. vitalii-infected blood, animals were monitored by blood smear examinations, which showed intra-erythrocytic forms of the parasite after five days post-inoculation (PI). Blood samples were collected to quantitate and separate platelets (Day 0, 12 and 21 PI) and to measure the enzymatic activities (Day 12 and 21 PI). The activity of NTPDase, 5'-nucleotidase and adenosine deaminase (ADA) was measured in platelets. A reduction (P<0.01) in the number of platelets was observed in R. vitalii-infected blood at Days 12 and 21 PI. At Day 12 PI, a reduction (P<0.01) in the hydrolysis of ATP, ADP and AMP, and deamination of adenosine was observed in dogs infected with R. vitalii. At Day 21 PI the ADA activity remained decreased, unlike the activity of NTPDase which increased (P<0.05). Based on these results we can conclude that ATP, ADP and AMP hydrolysis and adenosine deamination were altered in platelets of R. vitalii-infected dogs. Considering the importance of the purinergic system in hemostasis, it is believed that those changes contribute to the coagulation disorders and bleeding observed in R. vitalii-infected dogs and discussed in this manuscript., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the platelet count, coagulation time and platelet activity in dogs experimentally infected with Rangelia vitalii during the acute phase of the disease. For this study, 12 young dogs (females) were used, separated in two groups. Group A (uninfected control) was composed by healthy dogs (n=5), and group B consisted of R. vitalii-infected animals (n=7). After being inoculated with R. vitalii-infected blood, animals were monitored by blood smear examinations, which showed intra-erythrocytic forms of the parasite five days post-inoculation (PI). Blood samples were collected on days 0, 10, 20 and 30 PI. The material collected was placed in tubes containing EDTA for quantification of platelets, citrate anticoagulant platelet aggregation, and measuring the clotting time. Right after blood collection on days 10 and 20 PI, dogs were anesthetized for collecting bone marrow samples. A significant reduction (P<0.01) of the number of platelets was observed in R. vitalii-infected blood, when compared with uninfected dogs on days 10 and 20 PI. Additionally, macro-platelets were observed only in infected dogs. Prothrombin time and activated partial thromboplastin time did not differ between infected and uninfected dogs. The megakaryocyte count increased (P<0.01) significantly in infected dogs when compared with uninfected ones on days 10 and 20 PI. Platelet aggregation decreased (P<0.01) significantly in infected dogs in comparison to the control on days 10 and 20 PI. Therefore, rangeliosis in dogs causes a severe thrombocytopenia during the acute phase of infection. This platelets reduction probably occurred due to splenic sequestration and/or immune-mediated thrombocytopenia., (Copyright © 2011 Elsevier B.V. All rights reserved.)

In the beginning of the 20th century, a new canine disease was reported in Brazil under the name "nambiuvú", whose etiological agent was called Rangelia vitalii, a distinct piroplasm that was shown to parasitize not only erythrocytes, but also leucocytes and endothelial cells. In this new century, more publications on R. vitalii were reported from Brazil, including an extensive study on its ultrastructural analysis, in addition to clinical, pathological, and epidemiological data on nambiuvú. However, a molecular analysis of R. vitalii has not been performed to date. In the present study, we performed molecular phylogenetic analyses of R. vitalii based on fragments of the genes 18S rRNA and the heat shock protein 70 (hsp70), amplified by PCR performed on blood samples derived from five clinical cases of dogs presumably infected with R. vitalii in southern Brazil. In addition, we examined Giemsa-stained thin blood smears from these same dogs. DNA sequences (604-bp) of the 18S rRNA gene obtained from the five dogs were identical to each other, and by Blast analysis, this sequence shared the highest degree of sequence identity (95%) with Babesia sp. China-BQ1. DNA sequences (1056-bp) of the hsp70 gene obtained from the five dogs were identical to each other, and by Blast analysis, this sequence shared the highest degree of sequence identity (87%) with Babesia bigemina. Phylogenetic analyses inferred from either of the two genes resulted in the newly genotype being placed in the Babesia spp. sensu stricto clade with very high bootstrap support (95-100%) in three analyses (Neighbor-Joining, Maximum parsimony, and Maximum likelihood). Giemsa-stained thin blood smears from the dogs were shown to contain piroplasm organisms within erythrocytes, monocytes and neutrophils (individual forms), and schizont-like forms within neutrophils, in accordance with literature reports of R. vitalii. Based on these results, we conclude that R. vitalii, the etiological agent of "nambiuvú" in southern Brazil, is a valid species of piroplasm. Further studies are required to evaluate the validity of the genus Rangelia., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Recently we conducted the molecular characterization of Rangelia vitalii, a protozoan with high pathogenicity for young dogs in southern Brazil. To date, the descriptions of the disease have been restricted to natural infection cases. Therefore, this study aimed to evaluate the parasitemia, biological cycles and clinical-pathological findings in dogs experimentally infected with R. vitalii in the acute phase of disease, and also aimed to test a therapeutic protocol based on the diminazene aceturate. For this study, we used 12 young dogs (females), separated into two groups. Group A was composed of healthy dogs, not-infected (n=5), and Group B consisted of animals infected with R. vitalii (n=7). After infection, the animals were monitored by blood smear examinations, which showed intra-erythrocytic forms of the parasite 5 days post-infection (PI). Parasitemia increased progressively in these animals and had the highest peak of circulating parasites between 9 and 11 days PI. Subsequently, the parasitemia reduced and the protozoan was seen inside the leukocytes in days 17, 19 and 21 PI. The most prominent clinical signs observed at the 20 day PI of experiment were lethargy, fever and anorexia. We observed a decrease of hematocrit of infected animals compared with not-infected dogs, featuring a moderate anemia. Pathological evaluation of one dog in Group B at day 21 PI revealed splenomegaly, hepatomegaly, lymphadenopathy, and hemorrhages at necropsy. Histological examination showed only follicular hyperplasia in the spleen and lymph nodes, and the etiologic agent in the vascular endothelium. At 21 days PI, it was performed the treatment of dogs in Group B (n=6) with a single dose of diminazene aceturate, which showed a curative efficacy of 100% in cleaning R. vitalii from blood of infected dogs., (Copyright © 2011 Elsevier Inc. All rights reserved.)