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Background: Babesia species are intraerythrocytic protozoa, distributed in tropical and subtropical areas of the world, causing anemic diseases in many animals, including cattle. This disease, called babesisosis, is transmitted from one... more
Background: Babesia species are intraerythrocytic protozoa, distributed in tropical and subtropical areas of the world, causing anemic diseases in many animals, including cattle. This disease, called babesisosis, is transmitted from one animal to another through ticks (Tick Borne-Disease or TBD). On the other hand, Ecuador has a tropical climate that allows the development of the vector Rhipicephalus microplus, and therefore favors the transmission of Babesia spp. in cattle. Methods and principal findings: We determined the presence of Babesia spp. by PCR using 18s ribosomal gene as target (18s PCR) in 20 farms in the area of El Carmen (zone below 300 m above sea level) and 1 farm in Quito (2469 m.a.s.l.). In addition, we analyzed parameters such as age, sex, and packed cell volume (PCV) as explanatory variable associated with the disease. Results: The 18s PCR test showed that 18.94% (14.77% Babesia bovis and 4.17% Babesia bigemina) and 20.28% (14.69% B. bovis and 5.59% B. bigemina)...
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There are three trypanosoma species of veterinary importance in South America: (1) Trypanosoma evansi, the causative agent of derrengadera mechanically transmitted by bloodsucking insects such as tabanids, (2) Trypanosoma vivax, also... more
There are three trypanosoma species of veterinary importance in South America: (1) Trypanosoma evansi, the causative agent of derrengadera mechanically transmitted by bloodsucking insects such as tabanids, (2) Trypanosoma vivax, also mechanically transmitted by some dipteras hematophages as tabanids and/or Stomoxys, and (3) T. equiperdum, a tissue parasite adapted to sexual transmission and the causative agent of dourine, a distinctive disease that affects only Equidae. In order to evaluate the parasitological, hematological, and serological response of sheep infected with T. vivax, T. evansi, and T. equiperdum, four female sheep were experimentally infected with Venezuelan trypanosome field isolates: two T. evansi of differing virulences, one T. equiperdum; one T. vivax. Parasitemia and clinical parameters such as hematocrit, red blood cell count, hemoglobin, and body temperature were measured. T. evansi caused a chronic disease with undulant parasitemia alternating with some crypt...
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Trypanosomosis, a globally occurring parasitic disease, poses as a major obstacle to livestock production in tropical and subtropical regions resulting in tangible economic losses. In Latin America including Venezuela, trypanosomosis of... more
Trypanosomosis, a globally occurring parasitic disease, poses as a major obstacle to livestock production in tropical and subtropical regions resulting in tangible economic losses. In Latin America including Venezuela, trypanosomosis of ruminants is mainly caused by Trypanosoma vivax. Biologically active substances produced from trypanosomes, as well as host-trypanosome cellular interactions, contribute to the pathogenesis of anemia in an infection. The aim of this study was to examine with a scanning electron microscope the cellular interactions and alterations in ovine red blood cells (RBC) experimentally infected with T. vivax. Ovine infection resulted in changes of RBC shape as well as the formation of surface holes or vesicles. A frequent observation was the adhesion to the ovine RBC by the trypanosome's free flagellum, cell body, or attached flagellum in a process mediated by the filopodia emission from the trypanosome surface. The observed RBC alterations are caused by me...
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An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (MSP5) of Anaplasma marginale produced in Escherichia coli. Serum... more
An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (MSP5) of Anaplasma marginale produced in Escherichia coli. Serum antibody responses against MSP5 were detected in calves experimentally infected with A. marginale as early as 21 days postinfection and reached maximum titers at 28 days postinfection. The MSP5 ELISA performed with serum samples taken from field cattle from different regions of Venezuela showed a seroprevalence of 47%, which seems to be in accordance with the reported epidemiological status of bovine anaplasmosis in Venezuela. Positive results obtained in the MSP5 ELISA were further confirmed by immunoblotting, with the recombinant MSP5 as the antigen. Thus, these results confirmed the importance of MSP5 as a suitable antigen for the serological diagnosis of bovine anaplasmosis.
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Trypanosomosis caused by Trypanosoma vivax (T. vivax), is distributed in tropical and subtropical regions of Africa, Latin America and Asia, causing great economic losses. Previous biometric analysis report that T. vivax measures between... more
Trypanosomosis caused by Trypanosoma vivax (T. vivax), is distributed in tropical and subtropical regions of Africa, Latin America and Asia, causing great economic losses. Previous biometric analysis report that T. vivax measures between 18 and 31 μm; but few such studies have been conducted in Venezuela. The aim of this study was to describe and compare the morphometry of five isolates of T. vivax, to demonstrate the variability in size of the protozoa obtained from naturally-infected cattle in different geographical areas of Venezuela. To accomplish this, experimental infections were induced in sheep and blood samples were taken at the first peak of parasitemia. Micrographs of stages of hematozoa (20 micrographs of each specimen using scanning electron microscopy) were recorded for morphological studies. The results of this research revealed significant (p<0.05); (p<0.01) statistical differences in length among them. The total average length was 20.99 ± 2.10 μm, with variati...
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The mitochondrion role changes during the digenetic life cycle of African trypanosomes. Owing to the low abundance of glucose in the insect vector (tsetse flies) the parasites are dependent upon a fully functional mitochondrion, capable... more
The mitochondrion role changes during the digenetic life cycle of African trypanosomes. Owing to the low abundance of glucose in the insect vector (tsetse flies) the parasites are dependent upon a fully functional mitochondrion, capable of performing oxidative phosphorylation. Nevertheless, inside the mammalian host (bloodstream forms), which is rich in nutrients, parasite proliferation relies on glycolysis, and the mitochondrion is partially redundant. In this work we perform a comparative study of the mitochondrial genome (kinetoplast) in different strains of Trypanosoma vivax. The comparison was conducted between a West African strain that goes through a complete life cycle and two American strains that are mechanically transmitted (by different vectors) and remain as bloodstream forms only. It was found that while the African strain has a complete and apparently fully functional kinetoplast, the American T. vivax strains have undergone a drastic process of mitochondrial genome degradation, in spite of the recent introduction of these parasites in America. Many of their genes exhibit different types of mutations that are disruptive of function such as major deletions, frameshift causing indels and missense mutations. Moreover, all but three genes (A6-ATPase, RPS12 and MURF2) are not edited in the American strains, whereas editing takes place normally in all (editable) genes from the African strain. Two of these genes, A6-ATPase and RPS12, are known to play an essential function during bloodstream stage. Analysis of the minicircle population shows that its diversity has been greatly reduced, remaining mostly those minicircles that carry guide RNAs necessary for the editing of A6-ATPase and RPS12. The fact that these two genes remain functioning normally, as opposed to that reported in Trypanosoma brucei-like trypanosomes that restrict their life cycle to the bloodstream forms, along with other differences, is indicative that the American T. vivax strains are following a novel evolutionary pathway.
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Research Interests: Microbiology, Venezuela, Veterinary, Cell Division, Animals, and 15 moreMale, Monoclonal Antibodies, Economic Impact, Fisheries Sciences, Cattle, Anaplasma, Anaplasmosis, Bacteremia, North American, Molecular weight, Monoclonal Antibody, Liquid Scintillation Counting, Enzyme Linked Immunosorbent Assay, Antigens, and Anaplasma marginale
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Background Trypanosoma vivax is the earliest branching African trypanosome. This crucial phylogenetic position makes T. vivax a fascinating model to tackle fundamental questions concerning the origin and evolution of several features that... more
Background Trypanosoma vivax is the earliest branching African trypanosome. This crucial phylogenetic position makes T. vivax a fascinating model to tackle fundamental questions concerning the origin and evolution of several features that characterize African trypanosomes, such as the Variant Surface Glycoproteins (VSGs) upon which antibody clearing and antigenic variation are based. Other features like gene content and trans-splicing patterns are worth analyzing in this species for comparative purposes. Results We present a RNA-seq analysis of the bloodstream stage of T. vivax from data obtained using two complementary sequencing technologies (454 Titanium and Illumina). Assembly of 454 reads yielded 13385 contigs corresponding to proteins coding genes (7800 of which were identified). These sequences, their annotation and other features are available through an online database presented herein. Among these sequences, about 1000 were found to be species specific and 50 exclusive of ...
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Las enfermedades hemotropicas afectan animales que viven en zonas tropicales y subtropicales del mundo, debido a la presencia de vectores transmisores de los agentes, tales como garrapatas y moscas hematofagas. Dentro de este grupo de... more
Las enfermedades hemotropicas afectan animales que viven en zonas tropicales y subtropicales del mundo, debido a la presencia de vectores transmisores de los agentes, tales como garrapatas y moscas hematofagas. Dentro de este grupo de enfermedades se encuentran la anaplasmosis, tripanosomosis y babesiosis bovina, las cuales afectan negativamente las producciones ganaderas, por lo que el diagnostico certero permite el control y tratamiento racional de estas enfermedades. En Ecuador, estas enfermedades han sido poco estudiadas, por lo que el objetivo del presente trabajo fue realizar una prospeccion sobre la presencia de estos hemotropicos en la Provincia de Pastaza, para lo cual se evaluaron tres fincas ganaderas, ubicadas en la region Amazonica del Ecuador, Provincia de Pastaza, donde se realizo el diagnostico de anaplasmosis y tripanosomosis por ELISAi y babesiosis mediante la prueba de PCR. En esta evaluacion se obtuvo una prevalencia del 65,5 % de anticuerpos anti MSP5r de Anapla...
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Research Interests: Biology()
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Bovine trypanosomosis caused by Trypanosoma vivax, has a significant negative impact on livestock. Due to the limited information on the immune response against this parasite in ruminants, the present investigation was undertaken with the... more
Bovine trypanosomosis caused by Trypanosoma vivax, has a significant negative impact on livestock. Due to the limited information on the immune response against this parasite in ruminants, the present investigation was undertaken with the aim to evaluate and compare the immune response of sheep experimentally infected with two T. vivax isolates. The isolates were obtained from different geographic areas of Venezuela (TvLIEM176 from Trujillo State and TvMT1 from Monagas State). Three sheep were inoculated with each isolate and three others were used as controls for a total of nine animals. Every three days (d), during a period of 60 d, blood and serum samples were taken to determine anti-Trypanosoma spp. antibodies (by iELISA), parasitemia, white blood cell count and a leukocyte profile. TvMT1- inoculated animals showed higher levels of antibodies than TvLIEM176-infected animals, although parasitaemia behaved inversely. The TvLIEM176 isolate produced higher levels of parasitemia than...
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One of the common problems working with Trypanosoma vivax is its survival and cryopreservation, which originates loss of field isolates and parasitological examinations mistakes. The aim of this paper was to study the best methodologies... more
One of the common problems working with Trypanosoma vivax is its survival and cryopreservation, which originates loss of field isolates and parasitological examinations mistakes. The aim of this paper was to study the best methodologies for in vivo survival under field conditions and cryopreservation of the T. vivax. In order to study complete blood survival of T. vivax, two surviving conditions were tested at: room temperature and refrigeration at 4°C. The result shows that surviving in cooled sampled diminished significantly (P<0.01) compare with room temperature. Nevertheless, surviving of room temperature parasite begins to diminish after 6 hours, although some parasites remained viable up to 24 hours post-harvesting. Cryopreservation studies were made under three liquid nitrogen storage conditions: 1) gaseous phase 2) liquid and 3) gaseous/ liquid phase combination (glycerol 10% and DMSO 5%, were used as cryoprotectants). After two weeks and defrost the sur225 Recibido: 28 /...
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Anaplasma marginale causes a disease in cattle characterized by fever, anemia and decrease in milk and meat production. Small ruminants do not show signs of disease when infected, but it has been suggested they could act as reservoirs.... more
Anaplasma marginale causes a disease in cattle characterized by fever, anemia and decrease in milk and meat production. Small ruminants do not show signs of disease when infected, but it has been suggested they could act as reservoirs. Goat and sheep breeding is socially and economically important in arid and semi-arid areas in Venezuela, and these species often share space and food with cattle. The aim of this work was to detect antibodies against Anaplasma spp. in Venezuelan goat and sheep flocks. To accomplish this goal, an indirect ELISA using recombinant MSP5 as antigen of A. marginale was performed. Sera obtained from experimental infection in goat and a hyperimmune sheep serum were used as positive controls. Blood sera were obtained from 45 sheep and 48 goats located in Guarico State, an endemic area to bovine anaplasmosis. After standardization of assay for each species, 80.46% of the sheep and 59.25% of the goat sera showed to have antibodies against MSP5. No signs of clini...
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Bovine trypanosomosis, caused by Trypanosoma vivax has a significant negative impact on livestock. This research was performed with the aim of determining the immunoreactive proteins present in T. vivax . Thus, five sheep were... more
Bovine trypanosomosis, caused by Trypanosoma vivax has a significant negative impact on livestock. This research was performed with the aim of determining the immunoreactive proteins present in T. vivax . Thus, five sheep were experimentally infected with T. vivax TvZC1 isolate. Animal number 1 was used as the source of the trypanosomes and to prepare the soluble extract of parasites. Sheep numbers 2 to 5 were monitored for eight weeks and sera was obtained every two weeks for immunodetection. Parasites obtained from animal 1 were analyzed for T. vivax proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot (WB). The WB analysis showed three immunodominant proteins with a molecular mass of 42, 64 and 72 kDa, approximately. The 64 kDa protein was recognized by every animal during the complete infection period. The 72 kDa protein only was detected by animals 2, 3 and 5 during the infection course, whereas in animal 4 it was only detected durin...
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ABSTRACT Anaplasma marginale (A. marginale) is a bacterium of the Rickettsiales order that causes bovine anaplasmosis in tropical and subtropical regions worldwide. This disease, mainly transmitted by ticks and horseflies, typically... more
ABSTRACT Anaplasma marginale (A. marginale) is a bacterium of the Rickettsiales order that causes bovine anaplasmosis in tropical and subtropical regions worldwide. This disease, mainly transmitted by ticks and horseflies, typically develops in an initial acute stage, with clinical signs characterized by anemia and fever. After two months, animals recover their original physical condition and become asymptomatic, being unable to completely eliminate the bacterium, turning into persistently infected animals. This is due to the ability of A.marginale to evade the immune system. In this regard, the existence of a mechanism for antigenic variation in proteins of the bacterium, such as MSP1, MSP2, and MSP3, has been demonstrated. When assessing the multigenic family which encodes for MSP2, it was determined that it consists of two conserved regions flanking a central hypervariable region. Thus, when expressing each of the 52 MSP2 variables, a different epitope is also expressed. When the entire genome of this parasite was decoded, the presence of 16 pseudogenes for MSP2 was also discovered. These pseudogenes can be recombined within the operon expression site of MSP2, providing a second mechanism of variation. Moreover, both the hypervariable fragments and pseudogenes can combine among them, in a process called gene conversion, creating new “recombinant” epitopes, conferring the A. marginale with an almost infinite capacity for antigenic variability (third mechanism). A fourth mechanism of antigentic variation consists of the dimerization of MSP2 on the surface of A. marginale, because the simultaneous expression of variants creates unique epitopes. In conclusion, gene recombination of MSP2 along with the dimerization of MSP2 on the membrane provides a very efficient mechanism for antigenic variation for evading the host’s immune system.
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SUMMARY Bovine anaplasmosis is a disease caused by Anaplasma marginale (A. marginale), an intra erythrocytic bacteria classified within the a-proteobacterias. In Venezuela, 46% of cattle are infected with this disease producing major herd... more
SUMMARY Bovine anaplasmosis is a disease caused by Anaplasma marginale (A. marginale), an intra erythrocytic bacteria classified within the a-proteobacterias. In Venezuela, 46% of cattle are infected with this disease producing major herd losses. However, incidence of the disease in sheep is unknown. The objective of this work was to standardize the PCR technique for the detection of A. marginale in bovine and sheep blood. Ana19A and Ana19B specific primers were used to amplify the gene of Major Surface Protein 5 (MSP5). With the purpose of evaluating the standardized technique, bovine blood samples from an endemic zone were analyzed, resulting positive 40% of them. With respect to ovines, 25% of samples analyzed were positive. In conclusion, this technique has shown its versatility in the detection of Anaplasma sp. Another important aspect is that these results show the presence of MSP5 gene from Anaplasma sp. on small Venezuela’s ruminants, which before had not been determined by ...
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Bovine trypanosomosis, caused by Trypanosoma vivax has a significant negative impact on livestock. This research was performed with the aim of determining the immunoreactive proteins present in T. vivax. Thus, five sheep were... more
Bovine trypanosomosis, caused by Trypanosoma vivax has a significant negative impact on livestock. This research was performed with the aim of determining the immunoreactive proteins present in T. vivax. Thus, five sheep were experimentally infected with T. vivax TvZC1 isolate. Animal number 1 was used as the source of the trypanosomes and to prepare the soluble extract of parasites. Sheep numbers 2 to 5 were monitored for eight weeks and sera was obtained every two weeks for immunodetection. Parasites obtained from animal 1 were analyzed for T. vivax proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot (WB). The WB analysis showed three immunodominant proteins with a molecular mass of 42, 64 and 72 kDa, approximately. The 64 kDa protein was recognized by every animal during the complete infection period. The 72 kDa protein only was detected by animals 2, 3 and 5 during the infection course, whereas in animal 4 it was only detected during...
Research Interests: Biology()
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La tripanosomosis causada por Trypanosoma vivax, se encuentra distribuida en las regiones tropicales y subtropicales de Africa, America Latina y Asia, causando grandes perdidas economicas. Los analisis biometricos previos reportan que T.... more
La tripanosomosis causada por Trypanosoma vivax, se encuentra distribuida en las regiones tropicales y subtropicales de Africa, America Latina y Asia, causando grandes perdidas economicas. Los analisis biometricos previos reportan que T. vivax mide entre 18 y 31 μm; sin embargo, pocos estudios de este tipo se han realizado en Venezuela. El objetivo del presente estudio fue describir y comparar la morfometria de cinco aislados de T. vivax, con el proposito de demostrar la variabilidad en el tamano de los protozoarios obtenidos a partir de bovinos con infecciones activas en diferentes zonas geograficas del pais. Para ello, se realizaron infecciones experimentales en ovinos y se tomaron muestras de sangre en el primer pico de parasitemia. Se registraron microfotografias de los estadios hematozoicos (20 micrografias de microscopia electronica de barrido) de cada aislado para estudios morfologicos. Los resultados revelaron diferencias significativas (p<0,05); (p<0,01) en la longitu...
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La anaplasmosis, es una enfermedad producida por la bacteria Anaplasma marginale que esta ampliamente distribuida en Venezuela, originando efectos negativos en la salud y productividad de los rebanos bovinos. Hasta el presente se han... more
La anaplasmosis, es una enfermedad producida por la bacteria Anaplasma marginale que esta ampliamente distribuida en Venezuela, originando efectos negativos en la salud y productividad de los rebanos bovinos. Hasta el presente se han caracterizado 6 proteinas mayoritarias de superficie (MSP) de esta bacteria, de las cuales la MSP5, ha sido senalada como un excelente polipeptido para el diagnostico de la enfermedad, debido a que esta proteina es altamente conservada e inmunogenica. Esto ha motivado su clonamiento e insercion en un plasmido de E. coli, para usarla purificada como antigeno en ensayos inmunoenzimaticos. Sin embargo, estudios posteriores, indican que proteinas de E. coli recombinante que eluyen conjuntamente con la MSP5 durante el proceso de purificacion, interfieren en el ELISA originando falsos positivos. En el presente trabajo se estandarizo un ELISA indirecto, utilizando la MSP5 como antigeno y se logro disminuir las uniones inespecificas a las proteinas contaminante...
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SUMMARY Trypanosoma vivax and Trypanosoma evansi blood trypomastigotes, obtained respectively from sheep and mice experimentally infected, were used to isolate and characterize proteins using the partition Triton X-114 method. Results... more
SUMMARY Trypanosoma vivax and Trypanosoma evansi blood trypomastigotes, obtained respectively from sheep and mice experimentally infected, were used to isolate and characterize proteins using the partition Triton X-114 method. Results showed a different protein pattern between the 2 species. Additionally, results by Western blot, using sera from naturally infected animals, revealed specific discrimination between these two species of Trypanosoma. The potential use of this method as a reliable diagnostic tool is suggested.Key words: T. vivax, T. evansi, diagnosis, proteins. REFERENCIAS1. Anez-Rojas N., Garcia-Lugo P., Crisante G., Rojas A. & Anez N. (2006). Isolation, purification and characterization of GPI-anchored membrane proteins from Trypanosoma rangeli and Trypanosoma cruzi. Acta Tropica. 97: 140-145.2. Bolivar A. M., Garcia-Lugo P., Crisante G., Rojas A., Teixeira M. M. G. & Anez N. (2006). Deteccion de infecciones subclinicas por Trypanosoma vivax en bovinos de fincas ganaderas...
Anaplasma marginale ( A. marginale ), es una bacteria del orden de las Rickettsias que ocasiona la anaplasmosis bovina en regiones tropicales y subtropicales del mundo. Esta enfermedad, trasmitida principalmente por tabanos y garrapatas,... more
Anaplasma marginale ( A. marginale ), es una bacteria del orden de las Rickettsias que ocasiona la anaplasmosis bovina en regiones tropicales y subtropicales del mundo. Esta enfermedad, trasmitida principalmente por tabanos y garrapatas, se desarrolla tipicamente en una etapa inicial aguda con manifestaciones clinicas caracterizadas principalmente por anemia y fiebre. Despues de un par de meses, los animales recuperan su condicion fisica y se hacen asintomaticos, siendo incapaces de eliminar completamente la bacteria, convirtiendose en animales persistentemente infectados. Esto se debe a la capacidad de A. marginale para evadir el sistema inmune. En este sentido, se ha demostrado la existencia de un mecanismo de variacion antigenica en las proteinas MSP1, MSP2 y MSP3 de la bacteria. Al evaluar la familia multigenica que codifica para la MSP2, se determino que esta conformada por dos regiones conservadas que flanquean una region central hipervariable. De esta manera, al expresarse c...
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Resumen es: Uno de los problemas mas comunes del trabajo con Trypanosoma vivax, es la supervivencia y criopreservacion de este protozoario, lo cual origina perdida d...
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The objective of this research was the parasitology and serology evaluation of the presence of Anaplasma spp., Trypanosoma spp. y Babesia spp in white tail dear (Odocoileus virginianus) in a region of Apure State in which them coexist... more
The objective of this research was the parasitology and serology evaluation of the presence of Anaplasma spp., Trypanosoma spp. y Babesia spp in white tail dear (Odocoileus virginianus) in a region of Apure State in which them coexist with infected bovines (Bos taurus), horses (Equus caballus) and capybaras (Hydrochoerus hydrochaeris). For that, five whitetailed deer were captured in the Cedral Ranch, and the infection by these parasites where explored through blood smear and serological assays by inmunofluorescen and inmunoblot (Western Blot) using as antigens the soluble sonicated of Trypanosoma evansi and the recombinant Mayor Surface Protein (MSP5) of Anaplasma marginale. Two deers were detected positive for Anaplasma marginale by stained blood smear and no positives for Trypanosoma spp. or Babesia spp. One deer was seropositive for A. marginale and two were seropositive for Trypanosoma evansi. The above results suggest that the Odocoileus virginianus could be participating in t...
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An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (MSP5) of Anaplasma marginale produced in Escherichia coli. Serum... more
An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (MSP5) of Anaplasma marginale produced in Escherichia coli. Serum antibody responses against MSP5 were detected in calves experimentally infected with A. marginale as early as 21 days postinfection and reached maximum titers at 28 days postinfection. The MSP5 ELISA performed with serum samples taken from field cattle from different regions of Venezuela showed a seroprevalence of 47%, which seems to be in accordance with the reported epidemiological status of bovine anaplasmosis in Venezuela. Positive results obtained in the MSP5 ELISA were further confirmed by immunoblotting, with the recombinant MSP5 as the antigen. Thus, these results confirmed the importance of MSP5 as a suitable antigen for the serological diagnosis of bovine anaplasmosis.
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El diagnóstico serológico de la brucelosis se lleva a cabo por la detección de anticuerpos generados contra el liposacárido “LPS” o extractos bacterianos de células enteras por ELISA o pruebas de aglutinación. El objetivo del trabajo fue... more
El diagnóstico serológico de la brucelosis se lleva a cabo por la detección de anticuerpos generados contra el liposacárido “LPS” o extractos bacterianos de células enteras por ELISA o pruebas de aglutinación. El objetivo del trabajo fue evaluar una proteína recombinante que pueda ser usada en el diagnóstico serológico de la brucelosis bovina. Se escogió el gen de la Omp31 de Brucella melitensis 16M. El gen fue clonado a partir de ADN de B. melitensis. La expresión de la proteína Omp31r se realizó en un sistema de expresión procariota utilizando el vector pET28a y la purificación por cromatografía de afinidad a metales (IMAC). Un ELISA indirecto fue estandarizado utilizando sueros controles de bovinos positivos y negativos. La proteína Omp31r reaccionó con los sueros controles positivos y logró discriminarlos frente a los sueros negativos. La sensibilidad y especificidad del ensayo de ELISA fue de 77.2% y de 90.6%, respectivamente. Este sistema de ELISA indirecto puede ser útil para...
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Bovine trypanosomiasis is a chronic and debilitating disease caused by Trypanosoma vivax (T. vivax) with a negative impact on farm livestock. This protozoan is distributed in tropical and subtropical areas of the world and is mechanically... more
Bovine trypanosomiasis is a chronic and debilitating disease caused by Trypanosoma vivax (T. vivax) with a negative impact on farm livestock. This protozoan is distributed in tropical and subtropical areas of the world and is mechanically transmitted by vectors such as Tabanus spp. and Stomoxys calcitrans. The current prevalence of this parasite in Ecuador is completely unknown; in fact, there is only one report issued in 1977 by Wells et al., which indicates 22.5% by IFAT after evaluating approximately 20 sera
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Tripomastigotes sanguícolas de Trypanosoma vivax y Trypanosoma evansi obtenidos de infecciones experimentales en ovejas y ratones respectivamente, fueron utilizados para purificar y caracterizar proteínas citosólicas mediante el método de... more
Tripomastigotes sanguícolas de Trypanosoma vivax y Trypanosoma evansi obtenidos de infecciones experimentales en ovejas y ratones respectivamente, fueron utilizados para purificar y caracterizar proteínas citosólicas mediante el método de partición con Tritón X-114. Los resultados revelan diferencias en los patrones proteicos entre las dos especies. Asimismo, las reacciones antigénicas mediante Western blot utilizando suero de animales naturalmente infectados, permitió discriminar las infecciones entre ambos parásitos. Se sugiere la utilización de esta metodología como una prueba diagnóstica confiable. Palabras claves: T. vivax, T. evansi, diagnostico, proteínas. INTRODUCCIÓN Trypanosoma (Dutonella) vivax y Trypanosoma (Trypanozoon) evansi han sido incriminados como responsables de infecciones sufridas en una amplia gama de hospedadores en regiones tropicales y subtropicales de Suramérica, Asia y el norte de África. Entre los grupos mas afectados se destacan bovinos, equinos, bufali...
La enseñanza de las ciencias ha sido tema de discusión entre partidarios del aprendizaje por repetición y del aprendizaje por descubrimiento. Existen pocos estudios que comparan los efectos de ambos tipos de enseñanza en estudiantes... more
La enseñanza de las ciencias ha sido tema de discusión entre partidarios del aprendizaje por repetición y del aprendizaje por descubrimiento. Existen pocos estudios que comparan los efectos de ambos tipos de enseñanza en estudiantes universitarios. El estudio evalúa la eficacia del aprendizaje por descubrimiento en estudiantes universitarios de ciencia. Se diseñó y realizó un taller enmarcado en el tema de las aplicaciones de la biotecnología, siguiendo un diseño experimental con aplicación de pre-test, desarrollo del taller y aplicación de pos-test. El estadístico t-student permite señalar la efectividad del método, lo cual sugiere aplicar estrategias de enseñanza para favorecer el aprendizaje por descubrimiento de la biotecnología en estudiantes universitarios.
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Anaplasma marginale (A. marginale) is a bacterium of the Rickettsiales order that causes bovine anaplasmosis in tropical and subtropical regions worldwide. This disease, mainly transmitted by ticks and horseflies, typically develops in an... more
Anaplasma marginale (A. marginale) is a bacterium of the Rickettsiales order that causes bovine anaplasmosis in tropical and subtropical regions worldwide. This disease, mainly transmitted by ticks and horseflies, typically develops in an initial acute stage, with clinical signs characterized by anemia and fever. After two months, animals recover their original physical condition and become asymptomatic, being unable to completely eliminate the bacterium, turning into persistently infected animals. This is due to the ability of A.marginale to evade the immune system. In this regard, the existence of a mechanism for antigenic variation in proteins of the bacterium, such as MSP1, MSP2, and MSP3, has been demonstrated. When assessing the multigenic family which encodes for MSP2, it was determined that it consists of two conserved regions flanking a central hypervariable region. Thus, when expressing each of the 52 MSP2 variables, a different epitope is also expressed. When the entire g...
Research Interests: Biology()
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The objective of this research was the parasitology and serology evaluation of the presence of Anaplasma spp., Trypanosoma spp. y Babesia spp in white tail dear (Odocoileus virginianus) in a region of Apure State in which them coexist... more
The objective of this research was the parasitology and serology evaluation of the presence of Anaplasma spp., Trypanosoma spp. y Babesia spp in white tail dear (Odocoileus virginianus) in a region of Apure State in which them coexist with infected bovines (Bos taurus), horses (Equus caballus) and capybaras (Hydrochoerus hydrochaeris). For that, five whitetailed deer were captured in the Cedral Ranch, and the infection by these parasites where explored through blood smear and serological assays by inmunofluorescen and inmunoblot (Western Blot) using as antigens the soluble sonicated of Trypanosoma evansi and the recombinant Mayor Surface Protein (MSP5) of Anaplasma marginale. Two deers were detected positive for Anaplasma marginale by stained blood smear and no positives for Trypanosoma spp. or Babesia spp. One deer was seropositive for A. marginale and two were seropositive for Trypanosoma evansi. The above results suggest that the Odocoileus virginianus could be participating in t...
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Animal trypanosomiasis is a parasitic disease widespread in tropical and subtropical regions of Africa and America, becoming the main obstacle to the development and improvement of livestock in these regions. Economic losses caused by... more
Animal trypanosomiasis is a parasitic disease widespread in tropical and subtropical regions of Africa and America, becoming the main obstacle to the development and improvement of livestock in these regions. Economic losses caused by this disease are attributed to growth retardation, weight loss, decreased production of animal protein, cattle mortality and increased cost of treatment and veterinary care. In Venezuela, the disease is endemic to the Llanos, where it is mechanically transmitted by hematophagous Diptera (Stomoxys sp, Tabanus sp, Haematobia sp) and exhibits prevalences ranging between 40.5 and 66%. It is mainly caused by Trypanosoma vivax affecting bovines, goats and sheep. This paper describe the changes that occur in body temperature and weight, hematocrit, hemoglobin and plasma proteins of sheep during 45 days of experimental infection with LIEM-176 strain of T. vivax. Statistical analysis (ANOVA) showed significant differences between changes in body temperature, he...
Los hemotrópicos de los bovinos de interés veterinario en Latinoamérica son la anaplasmosis ocasionada por el Anaplasma marginale, la tripanosomosis por el Trypanosoma vivax y la babesiosis por Babesia bovis y Babesia bigemina. Estos... more
Los hemotrópicos de los bovinos de interés veterinario en Latinoamérica son la anaplasmosis ocasionada por el Anaplasma marginale, la tripanosomosis por el Trypanosoma vivax y la babesiosis por Babesia bovis y Babesia bigemina. Estos hemotrópicos tienen varias cosas en común; desde el punto de vista biológico, todos presentan tropismo por la sangre del bovino y desde el punto de vista clínico, los tres originan enfermedades caracterizadas por fiebre recurrente y descenso de los valores del hematrocrito. Esta fiebre recurrente aunada a la aparición de la anemia en los animales afectados, trae como consecuencias grandes pérdidas a los productores pecuarios por la inminente baja en la producción, sean estos animales de leche, carne o doble propósito. El impacto económico de estas enfermedades en Venezuela nunca se ha determinado en forma correcta. Sin embargo, según los datos de la Asociación Venezolana de la Industria de Salud Animal (AVISA) se estima que el año 2013, se gastaron más ...
The disease caused by T. vivax is commonly called Nagana in Africa and “secadera/cachera/cacho hueco/huequera” in parts of South America. This chapter will focus on the disease and its causative agent, reviewing new diagnostic methods,... more
The disease caused by T. vivax is commonly called Nagana in Africa and “secadera/cachera/cacho hueco/huequera” in parts of South America. This chapter will focus on the disease and its causative agent, reviewing new diagnostic methods, economic impact, chemotherapy, phylogenetic analysis of T. vivax isolates from Africa and South America, epidemiological studies in Latin America, and the analysis of recent genomic and transcriptomic data. T. vivax has a significant economic impact on livestock production in sub-Saharan Africa, where it is transmitted by the tsetse fly, and elsewhere in the African continent and in Central and South America, where it is transmitted mechanically. T. vivax is enzootic in most Latin American countries, and recurrent epizootic outbreaks causing significant morbidity and mortality have been reported over the past decades. Several significant landmarks in T. vivax research have been achieved in the last 2 years, including the publication of high-quality draft genome sequences and partial RNA-seq data for the Y486 strain, as well as the complete transcriptome of the LIEM-176 strain. Comparative analysis of the T. vivax, T. brucei, and T. congolense genomes revealed important differences in the surface proteins responsible for host immune response evasion in these species, and data from the T. vivax LIEM-76 transcriptome support the participation of other surface proteins, in addition to the VSG, in immune evasion. Proteins of the trans-sialidase family have been identified as important virulence factors that catalyze the desialylation of the host red blood cell, which in turn triggers the erythrophagocytosis that results in anemia. These findings will provide novel tools to tackle the challenge of controlling animal trypanosomosis caused by T. vivax in the developing world.
Research Interests: Biology()
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