RESUMEN
BACKGROUND: Bovine babesiosis is caused by infection with the protozoal parasite Babesia bovis, which is transmitted by Rhipicephalus (Boophilus) spp. It can cause mortality rates up to 90% in immunologically naive Bos taurus cattle. In south Texas, R. (B.) microplus is known to infest nilgai antelope (Boselaphus tragocamelus); however, their susceptibility to infection with B. bovis and their role in the transmission of the parasite remain unknown. In this study, we challenged nilgai antelope with B. bovis and evaluated their susceptibility to infection. METHODS: Nilgai were needle inoculated with ≈108 B. bovis-parasitized erythrocytes (merozoites) or a homogenate of B. bovis-infected larval ticks (sporozoite) delivered intravenously. Bos taurus beef calves were inoculated in parallel, as this strain of B. bovis is lethal to cattle. Temperature and hematocrit were monitored daily over the course of each study, and whole blood was collected for molecular [polymerase chain reaction (PCR)] and serological [indirect enzyme-linked immunosorbent assay (ELISA)] diagnostic evaluation. Histological sections of nilgai cerebral tissue were examined for evidence of infection. Recipient bovine calves were sub-inoculated with blood from nilgai challenged with either stage of the parasite, and they were monitored for clinical signs of infection and evaluated by a PCR diagnostic assay. Red blood cells (RBCs) from prechallenged nilgai and B. taurus beef cattle were cultured with an in vitro B. bovis merozoite culture to examine colonization of the RBCs by the parasite. RESULTS: Nilgai did not display clinical signs of infection upon inoculation with either the merozoite or sporozoite stage of B. bovis. All nilgai were PCR-negative for the parasite, and they did not develop antibodies to B. bovis. No evidence of infection was detected in histological sections of nilgai tissues, and in vitro culture analysis indicated that the nilgai RBCs were not colonized by B. bovis merozoites. Cattle subinoculated with blood from challenged nilgai did not display clinical signs of infection, and they were PCR-negative up to 45 days after transfer. CONCLUSIONS: Nilgai do not appear to be susceptible to infection with a strain of B. bovis that is lethal to cattle. Tick control on these alternative hosts remains a critical priority, especially given their potential to disseminate ticks over long distances.
Asunto(s)
Antílopes , Babesia bovis , Babesiosis , Animales , Babesia bovis/genética , Babesia bovis/patogenicidad , Babesia bovis/aislamiento & purificación , Babesia bovis/inmunología , Babesiosis/parasitología , Bovinos , Antílopes/parasitología , Enfermedades de los Bovinos/parasitología , Eritrocitos/parasitología , Texas , Virulencia , Rhipicephalus/parasitología , Femenino , Reacción en Cadena de la PolimerasaRESUMEN
Introduction: Babesia bovis, a tick-borne apicomplexan parasite causing bovine babesiosis, remains a significant threat worldwide, and improved and practical vaccines are needed. Previous studies defined the members of the rhoptry associated protein-1 (RAP-1), and the neutralization-sensitive rhoptry associated protein-1 related antigen (RRA) superfamily in B. bovis, as strong candidates for the development of subunit vaccines. Both RAP-1 and RRA share conservation of a group of 4 cysteines and amino acids motifs at the amino terminal end (NT) of these proteins. Methods and results: Sequence comparisons among the RRA sequences of several B. bovis strains and other Babesia spp parasites indicate a high level of conservation of a 15-amino acid (15-mer) motif located at the NT of the protein. BlastP searches indicate that the 15-mer motif is also present in adenylate cyclase, dynein, and other ATP binding proteins. AlphaFold2 structure predictions suggest partial exposure of the 15-mer on the surface of RRA of three distinct Babesia species. Antibodies in protected cattle recognize a synthetic peptide representing the 15-mer motif sequence in iELISA, and rabbit antibodies against the 15-mer react with the surface of free merozoites in immunofluorescence. Discussion and conclusion: The presence of the 15-mer-like regions in dynein and ATP-binding proteins provides a rationale for investigating possible functional roles for RRA. The demonstrated presence of a surface exposed B-cell epitope in the 15-mer motif of the B. bovis RRA, which is recognized by sera from protected bovines, supports its inclusion in future subunit epitope-based vaccines against B. bovis.
Asunto(s)
Antígenos de Protozoos , Babesia bovis , Babesiosis , Proteínas Protozoarias , Animales , Bovinos , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Anticuerpos Antiprotozoarios/inmunología , Antígenos de Protozoos/inmunología , Babesia bovis/inmunología , Babesiosis/inmunología , Babesiosis/parasitología , Babesiosis/prevención & control , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/prevención & control , Secuencia Conservada , Epítopos de Linfocito B/inmunología , Proteínas Protozoarias/inmunología , Vacunas Antiprotozoos/inmunologíaRESUMEN
The main objective of cattle breeders in tropical and subtropical regions is to acquire animals with taurine-productive traits adapted to the broad weather range of these regions. However, one of the main challenges on using taurine genetics in these areas is the high susceptibility of these animals to tick-borne diseases. Consequently, the present study evaluated from 10 November 2021-19 April 2022, the over 13 assessments, the Babesia bovis and Babesia bigemina DNA loads and the IgG anti-B. bovis and anti-B. bigemina levels in Angus (n = 17, 100% Taurine) and Ultrablack (n = 14, â¼82% taurine and 18% Zebu) calves. Data were analyzed using a multivariate mixed model with repeated measures of the same animal including the fixed effects of evaluation, genetic group, sex, Babesia spp., and their interactions. The repeatability values were estimated from the (co)variances matrix and expressed for each species. The correlations between the DNA loads (CNlog) and IgG titers (S/P) values for the two species were also estimated using the same model. Regarding the specific IgG antibody titers for both Babesia spp., no significant differences were observed between the two genetic groups. However, for B. bovis and B. bigemina DNA loads, Ultrablack calves presented significantly higher values than Angus calves. Under the conditions evaluated in this study, our findings suggest that the low percentage of Zebu genetic in the Ultrablack breed was insufficient to improve resistance against babesiosis. Further studies must demonstrate if the low percentages of Zebu genetics in Taurine breeds can modify the susceptibility to babesiosis infections.
Asunto(s)
Babesia , Babesiosis , Enfermedades de los Bovinos , Animales , Bovinos , Babesiosis/parasitología , Babesiosis/inmunología , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/inmunología , Babesia/genética , Babesia/inmunología , Femenino , Masculino , Antecedentes Genéticos , Babesia bovis/genética , Babesia bovis/inmunología , Inmunoglobulina G/sangre , Resistencia a la Enfermedad/genéticaRESUMEN
Abstract Serum and DNA samples from 15 naturally infected calves in Seropédica, Brazil, were obtained quarterly from birth to 12 months of age, in order to longitudinally evaluate their humoral immune response against Babesia bovis and the merozoite surface antigen diversity of B. bovis. Anti-B. bovis IgG antibodies were detected by an indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA). Using DNA amplification, sequencing and phylogenetic analysis, the genetic diversity of B. bovis was assessed based on the genes that encode merozoite surface antigens (MSA-1, MSA-2b and MSA-2c). The serological results demonstrated that up to six months of age, all the calves developed active immunity against B. bovis. Among the 75 DNA samples evaluated, 0, 3 and 5 sequences of the msa-1, msa-2b and msa-2c genes were obtained, respectively. The present study demonstrated that the msa-2b and msa-2c gene sequences amplified from blood DNA of B. bovis-positive calves were genetically diversified. These data emphasize the importance of conducting deeper studies on the genetic diversity of B. bovis in Brazil, in order to design diagnostic antigens and vaccines in the future.
Resumo Para avaliar longitudinalmente a resposta imune humoral anti-B. bovis e a diversidade genética de antígenos de superfície de merozoítos de B. bovis, entre bezerros naturalmente infectados em Seropédica, Brasil, amostras de soro e DNA de 15 bezerros foram obtidas trimestralmente, desde o nascimento até 12 meses de idade. Anticorpos IgG para B. bovis foram detectados pelos testes de Imunofluorescência Indireta e Ensaio de Imunoadsorção Enzimático Indireto. Usando-se amplificação de DNA, sequenciamento e análises filogenéticas, a diversidade genética de B. bovis, com base nos genes que codificam antígenos de superfície de merozoítos (MSA-1, MSA-2b e MSA-2c) foi investigada. Os resultados da sorologia demonstraram que, até os seis meses de idade, todos os bezerros desenvolveram imunidade ativa contra B. bovis. Entre as 75 amostras de DNA avaliadas, foram obtidas 0, 3 e 5 sequências dos genes msa-1, msa-2b e msa-2c. O presente estudo demonstrou que sequências dos genes msa-2b e msa-2c amplificadas a partir de amostras de sangue positivas para B. bovis de bezerros de Seropédica, foram geneticamente distintas. O presente trabalho realça a importância de se realizar estudos aprofundados sobre a diversidade genética de B. bovis no Brasil, objetivando o desenvolvimento de antígenos para o diagnóstico e vacinas no futuro.
Asunto(s)
Animales , Babesiosis/parasitología , Babesiosis/transmisión , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/transmisión , Babesia bovis/genética , Babesia bovis/inmunología , Filogenia , Variación Genética , Brasil , BovinosRESUMEN
Abstract Babesiosis is an economically important infectious disease affecting cattle worldwide. In order to longitudinally evaluate the humoral immune response against Babesia bovis and the merozoite surface antigen diversity of B. bovis among naturally infected calves in Taiaçu, Brazil, serum and DNA samples from 15 calves were obtained quarterly, from their birth to 12 months of age. Anti-B. bovis IgG antibodies were detected by means of the indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA). The polymerase chain reaction (PCR) was used to investigate the genetic diversity of B. bovis, based on the genes that encode merozoite surface antigens (MSA-1, MSA-2b and MSA-2c). The serological results demonstrated that up to six months of age, all the calves developed active immunity against B. bovis. Among the 75 DNA samples evaluated, 2, 4 and 5 sequences of the genes msa-1, msa-2b and msa-2c were obtained. The present study demonstrated that the msa-1 and msa-2b genes sequences amplified from blood DNA of calves positive to B. bovis from Taiaçu were genetically distinct, and that msa-2c was conserved. All animals were serologically positive to ELISA and IFAT, which used full repertoire of parasite antigens in despite of the genetic diversity of MSAs.
Resumo A babesiose é uma doença infecciosa economicamente importante que afeta o gado bovino em todo o mundo. Para avaliar longitudinalmente a resposta imune humoral contra B. bovis e a diversidade genética de antígenos de superfície de merozoítos de B. bovis, entre bezerros naturalmente infectados em Taiaçu, Brasil, amostras de soro e DNA de 15 bezerros, foram obtidos trimestralmente, desde o nascimento até aos 12 meses de idade. Os anticorpos IgG para B. bovis foram detectados pelos testes de Imunofluorescência Indireta e Ensaio de Imunoadsorção Enzimático Indireto. A Reação em Cadeia da Polimerase foi utilizada para investigar a diversidade genética de B. bovis, com base em genes que codificam antígenos de superfície de merozoítos (MSA-1, MSA-2b e MSA-2c). Os resultados da sorologia demonstraram que até seis meses de idade todos os bezerros desenvolveram imunidade ativa contra B. bovis. Entre as 75 amostras de DNA avaliadas, foram obtidas 2, 4 e 5 sequências dos genes msa-1, msa-2b e msa-2c. O presente trabalho demonstrou que as sequências dos genes msa-1 e msa-2b amplificadas do DNA do sangue de amostras positivas a B. bovis de bezerros de Taiaçu foram geneticamente distintas, e msa-2c conservadas. Todos os animais foram soropositivos ao ELISA e ao IFAT, os quais utilizaram o repertório completo de antígenos parasitários, apesar da diversidade genética dos MSAs.
Asunto(s)
Animales , Femenino , Bovinos , Babesiosis/inmunología , Variación Genética , Enfermedades de los Bovinos/inmunología , Babesia bovis/inmunología , Merozoítos/inmunología , Inmunidad Humoral , Antígenos de Superficie/genética , Brasil , Estudios LongitudinalesRESUMEN
The aim of this study was to determine the seroprevalence of antibodies against B. bovis and B. bigemina in calves from the region of Araguaína, State of Tocantins, Brazil. In this research we used sera obtained from 506 calves, from both genders and of 8 to 24 months old, to detect antibodies by indirect Enzyme-Linked Immunosorbent Assay (ELISA-test). Statistical analysis of the data was performed using the Chi-square (χ2) test with Yates correction. The seroprevalence obtained was 90.5 and 91.7 percent for B. bigemina and B. bovis, respectively, characterizing the region as an area of enzootic stability for the species analyzed. The seroprevalence to B. bovis showed higher positivity among calves 19-24 months old.
O objetivo desse estudo foi determinar a soroprevalência de anticorpos anti-B. bovis e anti-B. bigemina em bezerros da região de Araguaína, Estado do Tocantins, Brasil. Nesta pesquisa foram coletadas 506 amostras de soros de bezerros com faixa etária entre 8 e 24 meses, fêmeas e machos, as quais foram processadas pelo ensaio imunoenzimático indireto (ELISA-teste). Como análise estatística utilizou-se o Qui-Quadrado (χ2) com correção de Yates. As prevalências obtidas em bezerros foram de 90,5 e 91,7 por cento para B. bigemina e B. bovis, respectivamente, caracterizando esta região como de estabilidade enzoótica para as espécies analisadas. A soroprevalência para B. bovis apresentou maior positividade entre os bezerros com faixa etária de 19-24 meses.
Asunto(s)
Animales , Anticuerpos Antiprotozoarios/sangre , Babesia/inmunología , Babesiosis/veterinaria , Enfermedades de los Bovinos/sangre , Bovinos/sangre , Factores de Edad , Brasil , Babesia bovis/inmunología , Babesiosis/sangre , Babesiosis/epidemiología , Enfermedades de los Bovinos/epidemiología , Estudios SeroepidemiológicosRESUMEN
Babesia bovis is a tick-borne pathogen that remains an important constraint for the development of cattle industries in tropical and subtropical regions of the world. Effective control can be achieved by vaccination with live attenuated phenotypes of the parasite. However, these phenotypes have a number of drawbacks, which justifies the search for new, more efficient immunogens based mainly on recombinant protein technology. In the present paper, ribosomal phosphoprotein P0 from a Brazilian isolate of B. bovis was produced and evaluated with regard to conservation and antigenicity. The protein sequence displayed high conservation between different Brazilian isolates of B. bovis and several Apicomplexa parasites such as Theileria, Neospora and Toxoplasma. IgG from cattle experimentally and naturally infected with B. bovisas well as IgG1 and IgG2 from naturally infected cattle reacted with the recombinant protein. IgG from cattle experimentally infected with Babesia bigemina cross-reacted with B. bovis recombinant P0. These characteristics suggest that P0 is a potential antigen for recombinant vaccine preparations against bovine babesiosis.
Asunto(s)
Animales , Bovinos , Antígenos de Protozoos/sangre , Babesia bovis/inmunología , Proteínas Protozoarias , Proteínas Ribosómicas , Secuencia de Aminoácidos , Anticuerpos Antiprotozoarios/sangre , Brasil , Babesia bovis/aislamiento & purificación , Babesiosis/inmunología , Babesiosis/parasitología , Babesiosis/veterinaria , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Inmunoglobulina G/inmunología , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Proteínas Ribosómicas/genética , Proteínas Ribosómicas/inmunologíaRESUMEN
The objectives of this work were to determine the prevalence of Babesia bovis, Babesia bigemina, and Anaplasma marginale detecting antibodies in cattle raised in the semi-arid region of the state of Bahia, Brazil, through indirect enzyme linked immunosorbent assays (ELISA) and to compare the performances of indirect enzyme-linked immunosorbent assays with crude (I-ELISA-CrAnaAg) and recombinant major surface protein-5 (I-ELISA-MSP-5Ag), as antigens to detect antibodies against A. marginale. An stable enzootic area was found in Senhor do Bonfim and Euclides da Cunha for B. bovis that showed 86 and 95.5 percent of prevalence, respectively, and for B. bigemina with 90.8 and 91.3 percent. On the other hand, Uauá and Juazeiro, were characterized as enzootically unstable areas, since prevalences were: B. bovis - 63.7 and 56.4 percent and B. bigemina - 53 and 54.8 percent, respectively. The prevalence of A. marginale in the four municipalities was above 97 percent with I-ELISA-CrAnaAg and 94.8 percent with I-ELISA-MSP-5Ag which is an indication of stable enzootic condition for the rickettsia. The I-ELISA-CrAnaAg and I-ELISA-MSP-5Ag showed a highly significant association (r = 0.977), which means that both ELISA tests are suitable for epidemiological studies of A. marginale.
Asunto(s)
Animales , Bovinos , Anaplasma marginale/inmunología , Anaplasmosis/epidemiología , Anticuerpos Antibacterianos/sangre , Anticuerpos Antiprotozoarios/sangre , Babesia/inmunología , Babesiosis/epidemiología , Enfermedades de los Bovinos/epidemiología , Anaplasmosis/diagnóstico , Antígenos de Protozoos , Babesia bovis/inmunología , Babesiosis/diagnóstico , Brasil/epidemiología , Enfermedades de los Bovinos/diagnóstico , Ensayo de Inmunoadsorción Enzimática/métodos , Prevalencia , Proteínas Recombinantes , Estudios SeroepidemiológicosRESUMEN
El objetivo del trabajo fue evaluar la inocuidad y la capacidad inmunoprotectora de un inmunógeno combinado de Babesia bigemina y Babesia bovis a una dosis de 108 y 109, respectivamente, bajo un desafío controlado. En el primer experimento (inocuidad) se utilizaron 16 bovinos Holstein provenientes de una zona libre de garrapatas y negativos a anticuerpos contra Babesia spp, mediante la prueba de inmunofluorescencia indirecta (IFI), los cuales fueron inoculados, vía intramuscular, con 1 X 109 eritrocitos infectados (EI) con una cepa atenuada de B. bigemina y 108 EI de una clona irradiada de B. bovis, ambas derivadas de cultivo in vitro. Se observaron cambios en las constantes fisiológicas a partir del día 7 y hasta el día 14 posinoculación (PI) en los animales sin verse éstos físicamente afectados. El porcentaje de eritrocitos parasitados (PEP) fue <0.01 por ciento. El segundo experimento (inmunogenicidad), se realizó tres meses PI y consistió en el desafío de 8 de los animales del experimento 1 con cepas virulentas de ambas especies del protozoario a una dosis de 108 EI de cada una. Cuatro animales adicionales sirvieron como grupo testigo. El grupo inmunizado presentó ligera disminución en el volumen celular aglomerado (VCA) con temperatura rectal (TR) sin cambios y PEP de 0.06 y <0.01 para B. bigemina y B. bovis, respectivamente. El grupo testigo presentó TR mayor a 400C, disminución del VCA (29 por ciento) y el PEP fue de 0.5 para B. bigemina y 0.03 para B. bovis; estos animales requirieron tratamiento para evitar su muerte. Se concluye que el inmunógeno combinado de B. bigemina y B. bovis a dosis altas no provoca reacciones clínicas severas en animales susceptibles y proporciona una sólida protección al desafío controlado con cepas virulentas
Asunto(s)
Animales , Bovinos , Babesia/inmunología , Babesia/patogenicidad , Babesia bovis/inmunología , Babesia bovis/patogenicidad , Vacunas Sintéticas/uso terapéutico , Enfermedades de los Bovinos/inmunología , Inmunización/métodosRESUMEN
Se realizó un estudio descriptivo de casos, en éste se investigaron 781 sueros con la técnica de inmunofluorescencia indirecta con antígenos de Babesia bovis y Babesia bigemina en el Centro Nacional de Sanidad Agropecuaria. De ellos, 371 provenían de trabajadores agropecuarios y 410 de donantes de la provincia de Ciego de Avila. Se partió de diluciones de 1/64, a cada seropositivo se le confeccionó una encuesta epidemiológica para conocer factores de riesgo. Se empleó la prueba de diferencia de proporciones para comparar los porcentajes de positivos. Se calcularon las medias geométricas en ambos grupos y se procedió a su comparación con la prueba U de Mann Whitney. En los trabajadores agropecuarios se detectó un 7 por ciento con anticuerpos contra el 3,9 por ciento de los donantes (p < 0,05). Se encontró mayor circulación de Babesia bovis que de Babesia bigemina
Asunto(s)
Animales , Bovinos , Enfermedades de los Trabajadores Agrícolas , Babesia bovis/inmunología , Babesia/inmunología , Babesiosis/epidemiología , Babesiosis/inmunología , Donantes de Sangre , Enfermedades de los Bovinos/sangre , Técnica del Anticuerpo Fluorescente Indirecta , Epidemiología DescriptivaRESUMEN
Se realizó un estudio descriptivo de casos, en éste se investigaron 781 sueros con la técnica de inmunofluorescencia indirecta con antígenos de Babesia bovis y Babesia bigemina en el Centro Nacional de Sanidad Agropecuaria. De ellos, 371 provenían de trabajadores agropecuarios y 410 de donantes de la provincia de Ciego de Avila. Se partió de diluciones de 1/64, a cada seropositivo se le confeccionó una encuesta epidemiológica para conocer factores de riesgo. Se empleó la prueba de diferencia de proporciones para comparar los porcentajes de positivos. Se calcularon las medias geométricas en ambos grupos y se procedió a su comparación con la prueba U de Mann Whitney. En los trabajadores agropecuarios se detectó un 7 por ciento con anticuerpos contra el 3,9 por ciento de los donantes (p < 0,05). Se encontró mayor circulación de Babesia bovis que de Babesia bigemina(AU)
Asunto(s)
Animales , Bovinos , Babesiosis/epidemiología , Babesiosis/inmunología , Babesia bovis/inmunología , Babesia/inmunología , Donantes de Sangre , Técnica del Anticuerpo Fluorescente Indirecta , Enfermedades de los Bovinos/sangre , Enfermedades de los Trabajadores Agrícolas , Epidemiología DescriptivaRESUMEN
Uma preparaçäo antigênica bruta de Babesia bovis, preparada a partir de cultivo celular, foi liofilizada e utilizada em um teste de ELISA para detecçäo de anticorpos. O valor discriminante foi calculado pela média de amostras de soros negativos acrescida de dois desvios padröes. As duas séries de valores obtidas com antígeno liofilizado e antígeno congelado mostraram alta correlaçäo, indicando que a liofilizaçäo pode se constituir em uma alternativa prática para preservaçäo de antígenos de B. bovis para uso em ELISA
Asunto(s)
Animales , Anticuerpos , Antígenos , Babesia bovis/inmunología , Ensayo de Inmunoadsorción EnzimáticaRESUMEN
1. We describe the isolation of viable merozoites from erythrocytes infected with Babesia bovis or Babesia bigemina organisms by ammonium chloride lysis. 2. Parasite morphology was examined by both light and transmission electron microscopy. Erythrocyte-free parasites maintain their viability and infectivity, retain their antigenicity and are suitable for use in the indirect fluorescent antibody assay