Trypanosoma vivax Adhesion to Red Blood Cells in Experimentally Infected Sheep

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 mechanical and biochemical damage from host-parasite interactions occurring in the bloodstream. The altered erythrocytes are prone to mononuclear phagocytic removal contributing to the hematocrit decrease during infection.This research was supported by Project G-98003462-Fondo Nacional de Ciencia, Tecnología e Innovación (FONACIT), Caracas, Venezuela, and the Instituto de Estudios Científicos y Tecnológicos from Universidad Nacional Experimental Simón Rodríguez. The authors thank Beatriz Cajade for critical reading of this paper.S

Scanning electron microscopy of sperm alterations of siboney crossbred bulls

Los espermatozoides poseen un alto grado de polimorfismo. Se considera normal que hasta un 20% de ellos estén alterados en el eyaculado, mientras que un semen cuyo porcentaje de atiplas sea superior al 20%, se tiene como de baja calidad. La mayoría de tales alteraciones pueden ocurrir durante el tránsito y maduración a lo largo del epidídimo. Esas malformaciones pueden ser debido a factores genéticos, parasitarios, etarios, alimenticios, ecológicos, etc., que alteran el normal desarrollo de las diferentes etapas de la morfogénesis del esperma. El propósito del presente trabajo fue describir a través de microscopía electrónica de barrido, las alteraciones presentes en los espermatozoides de toros mestizos Siboney (5/8 Bos taurus, 3/8 Bos indicus), que no son detectadas por las pruebas convencionales. Para ello, a un grupo de cuatro toros tomados al azar, se les extrajo semen por electroeyaculación en dos ocasiones, en un intervalo de quince días, el cual se procesó para microscopía electrónica de barrido. Se observaron, además de las atipias detectables por microscopía óptica como: flagelos enrollados sobre si mismos, gotas citoplasmáticas y cabezas sin flagelos, otras alteraciones no detectables a ese nivel, tales como: desprendimiento de la membrana plasmática, pliegues de la misma membrana en la zona del acrosoma, restos vesiculares en la membrana que recubre la cabeza, desprendimiento de la misma con exposición del acrosoma. La observación, por microscopía electrónica de barrido de las alteraciones presentes en espermatozoides de toros, incrementó el número de atipias detectadas con respecto a lo reportado por los métodos convencionales. Al poder mostrar alteraciones que escapan del poder resolutivo del microscopio óptico, permite un diagnóstico de viabilidad más confiable, de manera que se puedan seleccionar los sementales adecuados para la inseminación natural y artificial, y así incrementar significativamente el porcentaje de fertilidad.235 - 242BimestralThe sperms posses a high polymorphism degree. It is considered normal that until 20% of them are altered in the ejaculated semen, while a semen whose atypical percentage is superior to 20%, has low quality. Most of such alterations could be happen during the traffic and maturation along the epididymis. Those malformations can be due to genetic, parasitic, age, nutritional and ecological factors, that alter the normal development of the different stages in the morphogenesis of the sperm. The purpose of the present work was to describe by scanning electron microscopy, the present alterations in the sperm of siboney crossbred bull (5/8 Bos taurus, 3/8 Bos indicus) that are no detected by the conventional tests. From four bulls taken at random, semen was extracted by electroejaculation in two times in an interval of fifteen days, and were processed for scanning electron microscopy. In addition to sperm cells alterations observed in light microscopy, such as: self coiled flagellum, in scanning electron microscopy were observed bovine spermatozoon with detachment of the plasmatic membrane, folds of the same membrane in acrosome area, vesicular structure and detachment of the head membrane with exposure of acrosome. These observations increased the number of malformations detected and reported by light microscopy. Therefore, scanning electron microscopy allows a more reliable diagnosis of viability of sperm cells, so that, the appropriate bull can be selected for natural and artificial in semination, and, in this way, to increase significantly the percentage of fertility

Effect of Trypanosoma vivax infection on semen quality of siboney Bull

Existen evidencias en las que toros africanos infectados experimentalmente con Trypanosoma vivax manifiestan un descenso en la calidad espermática, traduciéndose éste hecho en una posible disminución en la capacidad de fertilización. En el presente trabajo se determinan algunas de las alteraciones que causa sobre la calidad del esperma, la infección experimental con Trypanosoma vivax en toros tropicales tipo Siboney (5/8 Bos taurus, 3/8 Bos indicus). Para ello, un grupo de seis toros mestizos fueron tomados al azar, cuatro (4) de estos fueron inoculados con 106 trypanosomas/ml; los dos (2) toros restantes permanecieron como control. Los parámetros utilizados, pre y post-infección, para la evaluación espermática fueron: motilidad individual, concentración espermática, porcentaje de atípias y viabilidad celular. Paralelamente se recopilaron datos sobre el peso corporal, circunferencia escrotal, hematocrito, parasitemia y temperatura corporal. El experimento se llevo a cabo en un período de dieciocho semanas, durante las cuales los animales infectados presentaron parasitemias recurrentes, anemia, anorexia, aletargamiento, pérdida de equilibrio, debilidad, fiebre, Además, se observó un deterioro en la calidad del semen, que se manifestó como un aumento de las atípias, disminución de la viabilidad y concentración espermática. Es probable que esto afecte la capacidad de fertilización y por ende la productividad de cualquier rebaño expuesto a este parásito, con sus implicaciones negativas en el desarrollo socioeconómico de la actividad ganadera.411 - 417BimestralThere are evidences that African bulls infected experimentally with Trypanosoma vivax show lower spermatic quality, this fact can imply a possible decrease in the fertilization capacity. In the present work, we study, the effect of the experimental infection with Trypanosoma vivax in the quality of the semen of tropical bulls (Siboney: 3/8 Bos taurus, 5/8 Bos indicus), and some alterations of the sperm are determinated. A group of six crossbred bulls was taken at random, four of them, were inoculated intravenously with 106 trypanosomes/ml, and two bulls remained as control. The used parameters (obtained pre and post-infection) for the spermatic evaluation were: individual motility, spermatic concentration, percentage of atipias and cellular viability. At the same time, data were gathered on the corporal weight, scrotal circumference, hematocrit level, parasitemia and corporal temperature. The assay was carried out in a period of eighteen weeks, during which the infected animals presented recurrent parasitemias, anemia, anorexia, lethargy, balance loos, weakness and fever. Also, deterioration was observed in the quality of the semen, which showed as an increase of the atipias, decrease of the viability and spermatic concentration. This probably affects, the fertilization capacity, and therefore, the productivity of any exposed flock to T vivax with negative implications in the economic development of the cattle activity

Lectin-binding pattern in the kidney of mice experimentally infected with a venezuelan strain of Trypanosoma evansi

El Trypanosoma evansi es un hemoparásito que ocasiona la tripanosomosis equina en Venezuela. Esta enfermedad cursa con un incremento en la temperatura corporal, anemia, debilidad, parálisis y en algunos casos la muerte. Los mecanismos celulares del proceso infeccioso no se conocen con exactitud y pueden involucrar a los glicoconjugados de superficie del parásito y del hospedador. El propósito del presente estudio fue determinar las diferencias en el patrón de enlazamiento de las lectinas: sCon A, sWGA, PNA, SBA, UEA-I, LFA, SNA, y MAL-II en el riñón de ratones sanos e infectados con T. evansi. Para ello se realizó el marcaje sobre cortes en parafina de riñón utilizando el método del Complejo Avidina-Biotina (ABC). En controles se observó una reacción de moderada a intensa del endotelio glomerular con LFA, SNA y MAL-II mientras que en los animales infectados la reacción fue intensa. Los controles no experimentaron marcaje con sConA, sWGA, PNA y SBA a la vez que los infectados mostraron reacción mínima. El endotelio glomerular de los animales infectados no experimentó cambios en el enlazamiento de UEA-I con respecto a los controles. En los animales infectados, los eritrocitos y los túbulos contorneados proximales incrementaron su reactividad con SNA, y los componentes de la matriz extracelular con UEA-I. El marcaje con sWGA en la cápsula Bowmann de los riñones de animales infectados disminuyó con respecto a los controles. Estos resultados sugieren que en ratones infectados, los tripanosomas vivos o muertos pueden liberar componentes que alteran el patrón de glicoconjugados en las membranas celulares del riñón.431 - [email protected]@yahoo.comBimestralTrypanosoma evansi is the aethiological agent of equine trypanosomosis in Venezuela. This disease causes an increment in body temperature, anaemia, weakness and paralysis, finally causing the death of the host. The cellular mechanisms involved in the infectious process are not known and may involve the growth of superficial glycoconjugates with characteristic sugar residuals on the surfaces of both host and trypanosomes. The aim of the present study was to determine possible differences in the binding patterns of lectins: sCon A, sWGA, PNA, SBA, UEA-I, LFA, SNA, and MAL-II in kidneys of healthy mice and and mice infected with T. evansi. Sections of infected and control mice kidneys were labelled according to the Avidine-Biotine Complex (ABC) method. In controls and infected animals an intense reaction in the glomerular endothelium was observed with: LFA, SNA and MAL-II, and a low to moderate reaction with sCon A, sWGA, PNA, SBA, and UEA-I. In infected animals, the red blood cells and the Henle loop showed increased reactivity with SNA, and the components of the extracellular matrix with UEA-I. In infected animals the binding with SNA in the proximal convolute tubules and with PNA and sWGA in the renal capsule was reduced. These results suggest that in infected mice, living or dead trypanosomes might liberate biologically active products that alter the pattern of the glycoconjugates in the cell membranes of the kidney

Trypanosoma vivax

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 mechanical and biochemical damage from host-parasite interactions occurring in the bloodstream. The altered erythrocytes are prone to mononuclear phagocytic removal contributing to the hematocrit decrease during infection

Trypanosoma cruzi Necrotizing Meningoencephalitis in a Venezuelan HIV+-AIDS Patient: Pathological Diagnosis Confirmed by PCR Using Formalin-Fixed- and Paraffin-Embedded-Tissues

Coinfections with human immunodeficiency virus (HIV) and infectious agents have been recognized since the early 90s. In the central nervous system (CNS) of HIV+ patients, parasitic protozoans like Toxoplasma gondii have been described as responsible for the space occupying lesions (SOL) developed. However, the involvement of Trypanosoma cruzi is also described but appears to be less frequent in acquired immunodeficiency syndrome (AIDS) and transplant recipients, associated with necrotizing myocarditis and neurological symptoms related to the occurrence of necrotizing pseudotumoral encephalitis (NPE) and meningoencephalitis (NME). The present work aims to present a Venezuelan case of NME associated with the coinfection of HIV and a T. cruzi-like trypanosomatid as well as its evolution and diagnosis by histopathological techniques, electron microscopy, and PCR methods using formalin-fixed- (FF-) and paraffin-embedded- (PE-) tissues. Postmortem cytological studies of leptomeninges imprints reveal the presence of trypomastigotes of Trypanosoma sp. Histopathological and electron microscopy studies allowed us to identify an amastigote stage and to reject the involvement of other opportunistic microorganisms as the etiological agent of the SOL. The definitive confirmation of T. cruzi as the etiological agent was achieved by PCR suggesting that the NME by T. cruzi was due to a reactivation of Chagas’ disease