General characteristics of the life cycle of monogeneans and their incorporation to a scientific research program in parasitology

El Programa de Investigación Científca elaborado por Denegri (1991, 1997, 2002, 2008) está basado en la metodología y flosofía de la ciencia de Imre Lakatos (1978). Su cinturón protector tiene dos hipótesis fundamentales. La hipótesis de los ciclos biológicos se funda en el trabajo de Boskov (1986) y resalta patrones en los ciclos de vida de los cestodes, trematodes, nematodes y acantocéfalos. La hipótesis del desarrollo de comunidades está basada en el trabajo de varios ecólogos y postula cuatro modelos para las comunidades de parásitos. Aquí ampliaremos el contenido de la hipótesis de los ciclos biológicos incorporándole los patrones generales del ciclo de vida de los monogeneos.The Scientific Research Programme elaborated by Denegri (1991, 1997, 2002, 2008) is based on Imre Lakatos’s (1978) methodology and philosophy of science. Its protective belt has two fundamental hypothesis. The hypothesis of biological cycles is based on the work of Boskov (1986), and it highlights patterns among the life cycles of cestodes, trematodes, nematodes and acanthocephalans. The hypothesis of community development is based on the work of several ecologists, and it postulates four models for communities of parasites. Here we will extend the content of the hypothesis of biological cycles, incorporating general patterns of the life cycles of monogeneans.Fil: Denegri, Guillermo Maria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin

Effect of Different Terpene-Containing Essential Oils on the Proliferation of <i>Echinococcus granulosus</i> Larval Cells

Human cystic echinococcosis remains a major public health problem on several countries and the treatment strategies are not solved. The aim of the present work was to determine the in vitro effect of thymol and Mentha piperita, M. pulegium, and Rosmarinus officinalis essential oils on the proliferation of E. granulosus larval cells. Isolated cells and cellular aggregates were obtained from hydatid cyst's germinal layer and exposed to 1, 5, and 10 μg/ml of thymol and the different essential oils for 7 days. Drug effect was evaluated using test viability and scanning electron microscopy. Control cell culture viability was 2.1 x 10(6) (100%) after 7 days of incubation. At day 7, thymol 5 μg/ml caused a reduction in cell viability of 63% and the essential oils of M. piperita 10 μg/ml, M. pulegium 10 μg/ml, and R. officinalis 10 μg/ml produced a reduction in the viability of 77, 82, and 71%, respectively. Moreover essential oils caused reduction in cell number, collapsed cells, and loss of normal tridimensional composition of the aggregates. Due to the inhibitory effect caused by essential oils on E. granulosus cells we suggested that it would be an effective means for suppression of larval growth.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

In Vitro and In Vivo Effects of Tamoxifen against Larval Stage Echinococcus granulosus

Cystic echinococcosis is a zoonotic infection caused by the larval stage of the cestode Echinococcus granulosus. Chemotherapy currently employs benzimidazoles; however, 40% of cases do not respond favorably. With regard to these difficulties, novel therapeutic tools are needed to optimize treatment in humans. The aim of this work was to explore the in vitro and in vivo effects of tamoxifen (TAM) against E. granulosus. In addition, possible mechanisms for the susceptibility of TAM are discussed in relation to calcium homeostasis, P-glycoprotein inhibition, and antagonist effects on a putative steroid receptor. After 24 h of treatment, TAM, at a low micromolar concentration range (10 to 50 μM), inhibited the survival of E. granulosus protoscoleces and metacestodes. Moreover, we demonstrated the chemotherapeutic and chemopreventive pharmacological effects of the drug. At a dose rate of 20 mg/kg of body weight, TAM induced protection against the infection in mice. In the clinical efficacy studies, a reduction in cyst weight was observed after the administration of 20 mg/kg in mice with cysts developed during 3 or 6 months, compared to that of those collected from control mice. Since the collateral effects of high TAM doses have been largely documented in clinical trials, the use of low doses of this drug as a short-term therapy may be a novel alternative approach for human cystic echinococcosis treatment.Fil: Nicolao, María Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Elissondo, María Celina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Goya, Alejandra Beatriz. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Cumino, Andrea Carina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentin

Improvement of the In Vitro Culture of Echinococcus Granulosus Metacestodes

This work introduces a novel modification to the in vitro experimental vesiculardevelopment of the parasite. Our findings showed that protoscoleces exposed toinsulin developed into microcysts in shorter times. Moreover, a tenfold incrementin the yield of microcysts per tube was observed. An improvement of the in vitroculture of E. granulosus metacestodes was achieved. On the basis of this axenicin vitro system, biochemical, molecular and chemotherapeutical studies of E.granulosus will be greatly facilitated.Fil: Elissondo, María Celina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Pensel, Patricia Eugenia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentin

Effect of Different Terpene-Containing Essential Oils on the Proliferation of <i>Echinococcus granulosus</i> Larval Cells

Human cystic echinococcosis remains a major public health problem on several countries and the treatment strategies are not solved. The aim of the present work was to determine the in vitro effect of thymol and Mentha piperita, M. pulegium, and Rosmarinus officinalis essential oils on the proliferation of E. granulosus larval cells. Isolated cells and cellular aggregates were obtained from hydatid cyst's germinal layer and exposed to 1, 5, and 10 μg/ml of thymol and the different essential oils for 7 days. Drug effect was evaluated using test viability and scanning electron microscopy. Control cell culture viability was 2.1 x 10(6) (100%) after 7 days of incubation. At day 7, thymol 5 μg/ml caused a reduction in cell viability of 63% and the essential oils of M. piperita 10 μg/ml, M. pulegium 10 μg/ml, and R. officinalis 10 μg/ml produced a reduction in the viability of 77, 82, and 71%, respectively. Moreover essential oils caused reduction in cell number, collapsed cells, and loss of normal tridimensional composition of the aggregates. Due to the inhibitory effect caused by essential oils on E. granulosus cells we suggested that it would be an effective means for suppression of larval growth.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

Effect of Different Terpene-Containing Essential Oils on the Proliferation of <i>Echinococcus granulosus</i> Larval Cells

Human cystic echinococcosis remains a major public health problem on several countries and the treatment strategies are not solved. The aim of the present work was to determine the in vitro effect of thymol and Mentha piperita, M. pulegium, and Rosmarinus officinalis essential oils on the proliferation of E. granulosus larval cells. Isolated cells and cellular aggregates were obtained from hydatid cyst's germinal layer and exposed to 1, 5, and 10 μg/ml of thymol and the different essential oils for 7 days. Drug effect was evaluated using test viability and scanning electron microscopy. Control cell culture viability was 2.1 x 10(6) (100%) after 7 days of incubation. At day 7, thymol 5 μg/ml caused a reduction in cell viability of 63% and the essential oils of M. piperita 10 μg/ml, M. pulegium 10 μg/ml, and R. officinalis 10 μg/ml produced a reduction in the viability of 77, 82, and 71%, respectively. Moreover essential oils caused reduction in cell number, collapsed cells, and loss of normal tridimensional composition of the aggregates. Due to the inhibitory effect caused by essential oils on E. granulosus cells we suggested that it would be an effective means for suppression of larval growth.Facultad de Ciencias VeterinariasConsejo Nacional de Investigaciones Científicas y Técnica

Explanation and prediction of the presence of adult cestodes in pigs (Sus scrofa domesticus) based on a scientific research program in parasitology

La presencia de cestodes adultos en el cerdo doméstico tiene antecedentes inciertos. En base a la metodología de los Programas de Investigación Científica de Imre Lakatos, utilizamos el caso del cestode anoplocefálido Moniezia expansa, mostrando cómo el PIC en cuestión logró predecir su presencia en el cerdo doméstico. Brindamos también una explicación de los otros casos de cestodes adultos en cerdos documentados en la literatura especializada, haciendo hincapié en el trofismo de los hospedadores intermediarios y definitivos. Por último, ofrecemos unas consideraciones finales acerca de la distinción conceptual entre “hospedadores naturales” y “hospedadores no-naturales”, mostrando que esa distinción tiene menos utilidad en el presente que la que tenía en décadas previas, y hoy se puede apelar al concepto de potencialidad del fenómeno parasitario.The presence of adult cestodes in the domestic pig has uncertain antecedents. Basing ourselves on the methodology of Scientific Research Programs proposed by Imre Lakatos, we use the case of the anoplocephalid cestode Moniezia expansa, showing how the SRP in question managed to predict its presence in the domestic pig. We also provide an explanation of other cases of adult cestodes in domestic pigs that have been documented in the specialized literature, by emphasizing the feeding habits of the intermediate and definitive hosts. Finally, we offer some considerations on the conceptual distinction between “natural hosts” and “non-natural hosts”, showing that the difference in question has less utility in the present than it had in previous decades, and today it is possible to resort to the concept of potentiality of the parasitic phenomenon.Fil: Orensanz, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentin

Efficacy of Essential Oils of Thymus vulgaris and Origanum vulgare on Echinococcus granulosus

The aim of the present work was to determine the in vitro effect of T. vulgaris and O. vulgare essential oils against E. granulosus protoscoleces and cysts. Essential oils were added to the medium resulting in thymol final concentrations of 10 μg/mL. The essential oils had a time-dependent effect provoking the complete loss of protoscolex viability after 72 days of postincubation. The results were confirmed at the ultrastructure level. Loss of infectivity in protoscoleces incubated with O. vulgare after 60 days was observed. On the other hand, the weight of cysts recorded in mice inoculated with T. vulgaris treated protoscoleces was significantly lower than that obtained in control group. Gamma-glutamyl-transpeptidase activity was readily detected in the culture supernatant of protoscoleces treated either with the essential oils or thymol. T. vulgaris and O. vulgare essential oils and thymol can induce cell apoptosis of protoscoleces after short incubation times. The efficacy of T. vulgaris and O. vulgare essential oils was also demonstrated in vitro on E. granulosus murine cysts. Our data suggest that essential oils of T. vulgaris and O. vulgare have anthelmintic effect against protoscoleces and cysts of E. granulosus.Fil: Pensel, Patricia Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Maggiore, Marina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Gende, Liesel Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; ArgentinaFil: Eguaras, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; ArgentinaFil: Denegri, Guillermo Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Elissondo, María Celina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Zoonosis Parasitarias; Argentin

Development of an improved anesthesia protocol to increase CF1 mice survival in a portal vein infection with Echinococcus granulosus sensu lato protoscoleces

In order to optimize the survival rate of animals, the purpose of this study was to evaluate an injectable anesthesia protocol for the development of a murine model of hepatic cystic echinococcosis in female CF-1 mice. Three protocols of injectable anesthesia were evaluated during the infection of mice with Echinococcus granulosus sensu lato protoscoleces via the portal vein. The use or not of pre-anesthesia [atropine (0.4 mg/kg) and tramadol (2 mg/kg)] and the incorporation or not of yohimbine (0.5 mg/kg) (a reverser of xylazine) in mice anesthetized with ketamine/xylazine 80/8 mg/kg were evaluated. Most mice treated only with ketamine/xylazine 80/8 mg/kg did not achieve a deep surgical anesthetic plane. All mice treated with pre-anesthetic drugs achieved a deep surgical anesthetic plane after the administration of the anesthetic cocktail. Pre-anesthetic drugs application significantly reduced time induction of animals compared with those that received only anesthetic cocktail. Recovery time was significantly faster in the group that received yohimbine. Mice underwent laparotomy that did not receive yohimbine after surgery had a survival rate of 67%, whereas in the group treated with yohimbine the survival was 100 %. We recommend the protocol that applied pre-anesthetic drugs + ketamine/xylazine 80/8 mg/kg + yohimbine, as safe and reliable for the portal vein infection of mice with protoscoleces of E. granulosus sensu lato.Fil: Scioscia, Nathalia Paula. Universidad Nacional de Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Pensel, Patricia Eugenia. Universidad Nacional de Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Denegri, Guillermo Maria. Universidad Nacional de Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; ArgentinaFil: Elissondo, María Celina. Universidad Nacional de Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Zoonosis Parasitarias; Argentin

Endoparasitic infections in dogs from rural areas in the Lobos District, Buenos Aires province, Argentina

Dogs are definite hosts for several zoonotic helminthes and protozoan. Rural areas from the Lobos District in the northeast of Buenos Aires province, Argentina, are mainly used for livestock activity, increasing in this way the number of dogs on farms as well as the human risk of parasitic infections. The aims of this research were to evaluate the endoparasitic infections in dogs from farms in the Lobos District and analyze their zoonotic importance as well as several risk practices and habits of the rural population. Forty-two dog fecal samples obtained in 21 farms were analyzed through coproparasitological methods and coproantigen tests, which resulted in an overall parasite prevalence of 69.05% and 80.95% of the parasitized farms. The most frequent parasites were Trichuris vulpis and Eucoleus aerophila (26.19%), Echinococcus granulosus (19.05%), Uncinaria stenocephala and coccids (14.29%). The analysis of epidemiological files showed several habits of the rural population considered as risk factors associated with the presence of fecal samples parasitized and the presence of E. granulosus on the farms. It is clear that people involved with the farms studied were exposed to several helminthes that could cause serious diseases like cystic echinococcosis, which can become an important public health issue and affect the economy worldwideOs cães são hospedeiros definitivos de vários helmintos e protozoários zoonóticos. As áreas rurais do distrito de Lobos, no nordeste da província de Buenos Aires, Argentina, destinam-se principalmente à atividade pecuária aumentando desta forma o número de cães em fazendas, bem como o risco humano de infecções parasitárias. Os objetivos desta pesquisa foram avaliar as infecções endoparasitas em cães de fazendas do distrito de Lobos e analisar a sua importância zoonótica, bem como as práticas de risco e hábitos da população rural. Quarenta e duas amostras de fezes de cães obtidos em 21 fazendas foram analisadas pelos métodos coproparasitológicos e testes de coproantígenos, resultando numa prevalência de parasitas de 69,05% e 80,95% das propriedades parasitados. Os parasitas mais frequentes foram Trichuris vulpis e Eucoleus aerophila (26,19%), Echinococcus granulosus (19,05%), Uncinaria stenocephala e coccídeos (14,29%). A análise dos arquivos epidemiológicos mostraram vários hábitos da população rural como fatores de risco associados com a presença de amostras fecais parasitadas e a presença de E. granulosus em propriedades rurais. É evidente que as pessoas das fazendas estudadas foram expostas a vários helmintos que podem causar doenças graves como equinococose cística, que constitui importante problema de saúde pública e econômico a nível mundial.Fil: Dopchiz, Marcela Cecilia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lavallén, Carla Mariela. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bongiovanni, Roberto Antonio. Municipalidad de Lobos. Departamento de Bromatología y Zoonosis. Lobos; ArgentinaFil: Gonzalez, Patricia Verónica. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Elissondo, María Celina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Yannarella, Francisco. Universidad Nacional de La Plata; ArgentinaFil: Denegri, Guillermo Maria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin